The complement system comprises a complex array of enzymes and non-enzymatic proteins that is essential for the operation of the innate as well as the adaptive immune defence. The complement system ...can be activated in three ways: by the classical pathway which is initiated by antibody-antigen complexes, by the alternative pathway initiated by certain structures on microbial surfaces, and by an antibody-independent pathway that is initiated by the binding of mannan-binding lectin (MBL; first described as mannan-binding protein) to carbohydrates. MBL is structurally related to the complement C1 subcomponent, C1q, and seems to activate the complement system through an associated serine protease known as MASP (ref. 4) or p100 (ref. 5), which is similar to C1r and C1s of the classical pathway. MBL binds to specific carbohydrate structures found on the surface of a range of microorganisms, including bacteria, yeasts, parasitic protozoa and viruses, and exhibits antibacterial activity through killing mediated by the terminal, lytic complement components or by promoting phagocytosis. The level of MBL in plasma is genetically determined, and deficiency is associated with frequent infections in childhood, and possibly also in adults (for review, see ref. 6). We have now identified a new MBL-associated serine protease (MASP-2) which shows a striking homology with the previously reported MASP (MASP-1) and the two C1q-associated serine proteases C1r and C1s. Thus complement activation through MBL, like the classical pathway, involves two serine proteases and may antedate the development of the specific immune system of vertebrates.
Non-natural peptide analogs have significant potential for the development of new materials and pharmacologically active ligands. One such architecture, the β-peptoids (N-alkyl-β-alanines), has found ...use in a variety of biologically active compounds but has been sparsely studied with respect to folding propensity. Thus, we here report an investigation of the effect of structural variations on the cis–trans amide bond rotamer equilibria in a selection of monomer model systems. In addition to various side chain effects, which correlated well with previous studies of α-peptoids, we present the synthesis and investigation of cis–trans isomerism in the first examples of peptoids and β-peptoids containing thioamide bonds as well as trifluoroacetylated peptoids and β-peptoids. These systems revealed an increase in the preference for cis-amides as compared to their parent compounds and thus provide novel strategies for affecting the folding of peptoid constructs. By using NMR spectroscopy, X-ray crystallographic analysis, and density functional theory calculations, we present evidence for the presence of thioamide–aromatic interactions through Csp2 –H···Samide hydrogen bonding, which stabilize certain peptoid conformations.
Women with lichen sclerosus (LS) may suffer sexually because of dyspareunia, fissures, and introital narrowing. However, the literature remains limited on the biopsychosocial aspects of LS and its ...impact on sexual health.
To examine the biopsychosocial aspects and impact of LS on the sexual health of Danish women with vulvar LS.
The study was conducted with a mixed methods approach, including women with LS from a Danish patient association. The quantitative sample consisted of 172 women who completed a cross-sectional online survey that included 2 validated questionnaires: the Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale (FSDS). The qualitative sample consisted of 5 women with LS who volunteered for audiotaped, individual, semistructured interviews.
This mixed methods study combined data from 2 quantitative questionnaires (FSFI and FSDS) with qualitative interviews to achieve a comprehensive insight into the biopsychosocial aspects of sexual health in women living with LS.
The sexual function of women with LS was considerably affected, with FSFI scores below the cutoff value of 26.55, indicating a risk of sexual dysfunction. On average, 75% of the women were sexually distressed, with a total FSDS score of 25.47. Furthermore, 68% of the sexually active women were considerably affected in terms of sexual function and sexual distress, thus meeting international criteria for sexual dysfunction. However, a negative impact on sexual function was not always related to sexual distress and vice versa. The qualitative analysis identified 4 overarching themes: (1) decrease in or loss of sexual activity, (2) interference with relationship dynamics, (3) importance of sex and intimacy - loss and restoration, and (4) worries about sexual insufficiency.
Insight into the influence of LS on sexual health is important for health care professionals, including doctors, nurses, sex therapists, and physiotherapists, to provide the best guidance, support, and management for women with LS.
The strengths of the study are its use of a mixed methods design and the inclusion of sexual function and sexual distress. A limitation is related to the properties of the FSFI regarding women with no sexual activity.
LS has a considerable influence on women's sexual health in terms of sexual function and sexual distress, as supported by quantitative and qualitative measures. Our understanding of the complex interactions among sexual activity, intimate relations, and causes of psychological distress has been enriched.
Bleeding is associated with a significantly increased morbidity and mortality. Bleeding events are often described in the unstructured text of electronic health records, which makes them difficult to ...identify by manual inspection.
To develop a deep learning model that detects and visualizes bleeding events in electronic health records.
Three hundred electronic health records with International Classification of Diseases, Tenth Revision diagnosis codes for bleeding or leukemia were extracted. Each sentence in the electronic health record was annotated as positive or negative for bleeding. The annotated sentences were used to develop a deep learning model that detects bleeding at sentence and note level.
On a balanced test set of 1178 sentences, the best‐performing deep learning model achieved a sensitivity of 0.90, specificity of 0.90, and negative predictive value of 0.90. On a test set consisting of 700 notes, of which 49 were positive for bleeding, the model achieved a note‐level sensitivity of 1.00, specificity of 0.52, and negative predictive value of 1.00. By using a sentence‐level model on a note level, the model can explain its predictions by visualizing the exact sentence in a note that contains information regarding bleeding. Moreover, we found that the model performed consistently well across different types of bleedings.
A deep learning model can be used to detect and visualize bleeding events in the free text of electronic health records. The deep learning model can thus facilitate systematic assessment of bleeding risk, and thereby optimize patient care and safety.
Mammalian stanniocalcin-2 (STC2) is a secreted polypeptide widely expressed in developing and adult tissues. However, although transgenic expression in mice is known to cause severe dwarfism, and ...targeted deletion of STC2 causes increased postnatal growth, its precise biological role is still unknown. We found that STC2 potently inhibits the proteolytic activity of the growth-promoting metalloproteinase, pregnancy-associated plasma protein-A (PAPP-A). Proteolytic inhibition requires covalent binding of STC2 to PAPP-A and is mediated by a disulfide bond, which involves Cys-120 of STC2. Binding of STC2 prevents PAPP-A cleavage of insulin-like growth factor-binding protein (IGFBP)-4 and hence release within tissues of bioactive IGF, required for normal growth. Concordantly, we show that STC2 efficiently inhibits PAPP-A-mediated IGF receptor signaling in vitro and that transgenic mice expressing a mutated variant of STC2, STC2(C120A), which is unable to inhibit PAPP-A, grow like wild-type mice. Our work identifies STC2 as a novel proteinase inhibitor and a previously unrecognized extracellular component of the IGF system.
Background: The biological function and biochemical activity of mammalian stanniocalcin-2 are unknown.
Results: Stanniocalcin-2 inhibits proteolytic release of insulin-like growth factor (IGF), and its ability to cause growth retardation upon transgenic overexpression in mice depends on its proteinase inhibitory function.
Conclusion: Stanniocalcin-2 is a novel component of the IGF axis.
Significance: Altered stanniocalcin-2 expression may affect IGF signaling under pathological conditions.
In today's short stay hospital settings the contact time for patients is reduced. However, it seems to be more important for the patients that the healthcare professionals are easy to get in contact ...with during the whole course of treatment, and to have the opportunity to exchange information, as a basis for obtaining individualized information and support. Therefore, the aim was to explore the ability of a dialogue-based application to contribute to accessibility of the healthcare professionals and exchangeability of information.
An application for online written and asynchronous contacts was developed, implemented in clinical practice, and evaluated. The qualitative effect of the online contact was explored using a Web-based survey comprised of open-ended questions.
Patients valued the online contacts and experienced feelings of partnership in dialogue, in a flexible and calm environment, which supported their ability to be active partners and feelings of freedom and security.
The online asynchronous written environment can contribute to accessibility and exchangeability, and add new possibilities for dialogues from which the patients can benefit. The individualized information obtained via online contact empowers the patients. The Internet-based contacts are a way to differentiate and expand the possibilities for contacts outside the few scheduled face-to-face hospital contacts.
The aim of the present study was to assess, compare, and correlate the pain response to an experimental pain stimulus (hyperalgesia to pressure pain threshold (PPT) measured from different body ...sites), the pain intensity (VAS) of the habitual pain, and quality of life parameters (SF-36) in groups of females with chronic non-malignant pain syndromes. Forty female pain patients with fibromyalgia/whiplash (
n
=
10), endometriosis (
n
=
10), low back pain (
n
=
10), or rheumatoid arthritis (
n
=
10), as well as 41 age-matched healthy female controls participated in the study.
The fibromyalgia/whiplash patients scored significantly higher (
p
<
0.04) VAS ratings (median rating
=
7.0) than the endometriosis (6.0), low back pain (6.0), and rheumatoid arthritis (3.5) patients. All fours patient groups had significantly lower PPTs at all sites as compared with controls.
The fibromyalgia/whiplash patients experienced the highest influence of pain on their overall health status, particularly vitality, social function, emotional problems, and mental health. A significant negative correlation was found between VAS rating and quality of life (
p
<
0.04). Significant correlation (
p
<
0.05) was found between pressure hyperalgesia measured at lowest PPT sites and the impairment of SF-36 physical function as well as mental health parameters.
This study demonstrates significant generalised pressure hyperalgesia in four groups of chronic pain patients, correlations between degree of pressure hyperalgesia and impairment of some quality of life parameters, and increased pain intensity of the ongoing pain is associated with decreased quality of life.
Normal brain development depends on tight temporal and spatial regulation of connections between cells. Mutations in L1cam, a member of the immunoglobulin (Ig) superfamily that mediate cell-cell ...contacts through homo- and heterophilic interactions, are associated with several developmental abnormalities of the nervous system, including mental retardation, limb spasticity, hydrocephalus, and corpus callosum aplasia. L1cam has been reported to be shed from the cell surface, but the significance of this during different phases of brain development is unknown. We here show that ADAM10-mediated shedding of L1cam is regulated by its fibronectin type III (FNIII) domains. Specifically, the third FNIII domain is important for maintaining a conformation where access to a membrane proximal cleavage site is restricted. To define the role of ADAM10/17/BACE1-mediated shedding of L1cam during brain development, we used a zebrafish model system. Knockdown of the zebrafish, l1camb, caused hydrocephalus, defects in axonal outgrowth, and myelination abnormalities. Rescue experiments with proteinase-resistant and soluble L1cam variants showed that proteolytic cleavage is not required for normal axonal outgrowth and development of the ventricular system. In contrast, metalloproteinase-mediated shedding is required for efficient myelination, and only specific fragments are able to mediate this stimulatory function of the shedded L1cam.
The metalloproteinase pregnancy-associated plasma protein-A (PAPP-A) cleaves both insulin-like growth factor (IGF)-binding protein 4 (IGFBP-4) and -5 at a single site in their central domain causing ...the release of bioactive IGF. Inhibition of IGF signaling is relevant in human disease, and several drugs in development target the IGF receptor. However, inhibition of PAPP-A activity may be a valuable alternative. We have generated monoclonal phage-derived single chain fragment variable (scFv) antibodies which selectively inhibit the cleavage of IGFBP-4 by PAPP-A, relevant under conditions where cleavage of IGFBP-4 represents the final step in the delivery of IGF to the IGF receptor. None of the antibodies inhibited the homologous proteinase PAPP-A2, which allowed mapping of antibody binding by means of chimeras between PAPP-A and PAPP-A2 to the C-terminal Lin12-Notch repeat module, separated from the proteolytic domain by almost 1000 amino acids. Hence, the antibodies define a substrate binding exosite that can be targeted for the selective inhibition of PAPP-A proteolytic activity against IGFBP-4. In addition, we show that the Lin12-Notch repeat module reversibly binds a calcium ion and that bound calcium is required for antibody binding, providing a strategy for the further development of selective inhibitory compounds. To our knowledge these data represent the first example of differential inhibition of cleavage of natural proteinase substrates by exosite targeting. Generally, exosite inhibitors are less likely to affect the activity of related proteolytic enzymes withsimilar active site environments. In the case of PAPP-A, selective inhibition of IGFBP-4 cleavage by interference with exosite binding is a further advantage, as the activity against other known or unknown PAPP-A substrates, whose cleavage may not depend on binding to the same exosite, is not targeted.
Pregnancy-associated plasma protein-A (PAPP-A), originally known from human pregnancy serum, has recently been demonstrated to be a metzincin superfamily metalloproteinase involved in normal and ...pathological insulin-like growth factor (IGF) physiology. PAPP-A specifically cleaves IGF-binding protein (IGFBP)-4, one of six antagonists of IGF action, which results in release of IGF bound to IGFBP-4. IGFBP-4 is the only known PAPP-A substrate. Its cleavage by PAPP-A uniquely depends on the presence of IGF. We here report mammalian expression and purification of recombinant 1547-residue PAPP-A (rPAPP-A). The recombinant protein is secreted as a homodimer of about 400 kDa composed of two 200-kDa disulfide-bound subunits. Antigenically and functionally, rPAPP-A behaves like the native protein. In human pregnancy, PAPP-A is known to circulate as a 500-kDa disulfide-bound 2:2 complex with the proform of eosinophil major basic protein (proMBP), PAPP-A/proMBP. A comparison between rPAPP-A and pregnancy serum PAPP-A/proMBP complex surprisingly reveals a difference greater than 100-fold in proteolytic activity, showing that proMBP functions as a proteinase inhibitor in vivo. We find that polyclonal antibodies against PAPP-A abrogate all detectable IGFBP-4 proteolytic activity in pregnancy serum, pointing at PAPP-A as the dominating, if not the only, IGFBP-4 proteinase present in the circulation. We further show that pregnancy serum and plasma contain traces (<1%) of uncomplexed PAPP-A with a much higher specific activity than the PAPP-A/proMBP complex. The measurable activity of the PAPP-A/proMBP complex probably results from the presence of a minor subpopulation of partly inhibited PAPP-A that exists in a 2:1 complex with proMBP. Inhibition of PAPP-A by proMBP represents a novel inhibitory mechanism with the enzyme irreversibly bound to its inhibitor by disulfide bonds.
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