Fesselin binds to actin and myosin and inhibits actin-activated ATPase activity

Fesselin is an actin binding protein that bundles actin filaments and accelerates nucleation of actin polymerization. The effect of fesselin on actin polymerization is regulated by Ca⁺⁺-calmodulin. Because actin filaments serve both structural and contractile functions we also examined the effect of fesselin on activation of myosin S1 ATPase activity. Fesselin inhibited the activation of S1-catalyzed ATP hydrolysis in a similar manner in both the presence and absence of tropomyosin. This inhibition was unaffected by Ca⁺⁺-calmodulin. Fesselin inhibited the binding of myosin-S1 to actin during steady-state ATP hydrolysis. Fesselin also displaced caldesmon from actin. S1 displaced fesselin from actin in the absence of nucleotide when the affinity of S1 for actin was much greater than the affinity of fesselin for actin. It is likely that fesselin and S1 share common binding sites on F-actin. We also observed that fesselin could bind to smooth muscle myosin with μM affinity. Fesselin shares some similarities to caldesmon in binding to several other proteins and having multiple potential functions. Parts of this work were presented in preliminary form at the 45th Annual Biophysical Society Meeting, Baltimore, MD, February 2004 and the 46th Annual Meeting, Long Beach, CA, February 2005.     

Distinctly different rates of benzocaine action on sodium channels of Ranvier nodes kept open by chloramine-T and veratridine

Single myelinated nerve fibres of the frog, Rana esculenta, were voltage clamped in a fast-exchange chamber in the presence of 10 mM TEA to block potassium channels. After treatment with 0.6 mM chloramine-T for 1-4 min a sizeable INa component persisted even during a 14-s depolarizing impulse. Changing the perfusate to Ringer solution + 1 mM benzocaine resulted in a fast reduction (half time ca. 0.06 s) of the persistent INa, comparable to the rate of block of peak INa during a series of short impulses before chloramine-T. In the presence of 60 microM veratridine the peak INa was followed by a slow exponential (tau s) reincrease of inward current, Is, that did not appreciably inactivate. Application of 0.25 mM benzocaine during a 14-s depolarizing impulse caused Is to decrease exponentially with a large time constant, tau on of 4.3 s. Recovery on washout proceeded with tau off = 3.4s. Tau on was little dependent on benzocaine concentration and was 4.5 s on the average in 1 mM. Tau on in 25 microM was insignificantly (15%) larger than in 1 mM if tested on the same fibre. After equilibration in 25 microM, 0.25 mM and 1 microM, Is(t = 14s) was reduced to 0.69, 0.30, and 0.10, respectively, of the value without anaesthetic. Cooling by only 4-5 degrees C reduced Is and much increased tau s. tau on (1 mM benzocaine) increased almost in proportion to tau s. Tail currents during a series of pulses (1.1 s every 2.5 s) were reduced by 0.25 mM benzocaine clearly faster (tau on = 1.3 s) than Is during a long pulse of the same amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)     

Multidisciplinary long‐term care and modern surgical treatment of congenital melanocytic nevi – recommendations by the CMN surgery network

In recent years, our knowledge of congenital melanocytic nevi (CMN) has greatly expanded. This has led to a paradigm shift. The present article represents a commentary by an interdisciplinary group of physicians from German‐speaking countries with extensive experience in long‐term care and surgical treatment of children and adults with CMN (CMN surgery network, “Netzwerk Nävuschirurgie”, NNC). The authors address aspects such as the indication for treatment as well as treatment planning and implementation under these new premises. Adequate counseling of parents on conservative and/or surgical management requires an interdisciplinary exchange among physicians and individualized planning of the intervention, which frequently involves a multi‐stage procedure. Today, the long‐term aesthetic outcome is at the center of any therapeutic endeavor, whereas melanoma prevention plays only a minor role. The premise of “removal at any cost” no longer holds. Potential treatment‐related adverse effects (hospitalization, wound healing disorders, and others) must be carefully weighed against the prospects of a beneficial outcome. In this context, the use of dermabrasion in particular must be critically evaluated. At a meeting of the NNC in September 2018, its members agreed on a consensus‐based position on dermabrasion, stating that the procedure frequently leads to impaired wound healing and cosmetically unfavorable or hypertrophic scarring. Moreover, dermabrasion is considered to be commonly associated with considerable repigmentation that usually occurs a number of years after the procedure. In addition, the NNC members saw no benefit in terms of melanoma prevention. In the future, physicians should therefore thoroughly caution about the potential risks and often limited cosmetic benefits of dermabrasion.     

Highly efficient magnetic stem cell labeling with citrate-coated superparamagnetic iron oxide nanoparticles for MRI tracking

Tracking of transplanted stem cells is essential to monitor safety and efficiency of cell-based therapies. Magnetic resonance imaging (MRI) offers a very sensitive, repetitive and non-invasive in vivo detection of magnetically labeled cells but labeling with commercial superparamagnetic iron oxide nanoparticles (SPIONs) is still problematic because of low labeling efficiencies and the need of potentially toxic transfection agents. In this study, new experimental citrate-coated SPIONs and commercial Endorem and Resovist SPIONs were investigated comparatively in terms of in vitro labeling efficiency, effects on stem cell functionality and in vivo MRI visualization. Efficient labeling of human mesenchymal stem cells (MSCs) without transfection agents was only achieved with Citrate SPIONs. Magnetic labeling of human MSCs did not affect cell proliferation, presentation of typical cell surface marker antigens and differentiation into the adipogenic and osteogenic lineages. However, chondrogenic differentiation and chemotaxis were significantly impaired with increasing SPION incorporation. Transplanted SPION-labeled MSCs were visualized in vivo after intramuscular injection in rats by 7T-MRI and were retrieved ex vivo by Prussian Blue and immunohistochemical stainings. Though a careful titration of SPION incorporation, cellular function and MRI visualization is essential, Citrate SPIONs are very efficient intracellular magnetic labels for in vivo stem cell tracking by MRI.     

Immunolocalization of defensins and cathelicidin in human glands of Moll.

The human gland of Moll located at the margin of the eyelids is a specialized apocrine gland, the function of which is not exactly known. The presence of antimicrobial proteins was identified in this gland recently, suggesting a function in the external ocular defense barrier against pathogens. In this study, we have demonstrated beta-defensin-1, beta-defensin-2 and cathelicidin (LL-37) in the secretory endpieces of the glands of Moll using immunohistochemical methods. beta-Defensin-1, beta-defensin-2 and cathelicidin (LL-37) showed a weak to moderately intensive staining pattern. The strongest immunolocalization of beta-defensin-1 was observed in the apical protrusions of the gland, which could also be observed but to a lesser extent in the case of beta-defensin-2 and cathelicidin. In active glandular cells, a granular staining pattern could be observed. beta-Defensin-1 and beta-defensin-2 varied in staining intensities, and even within one section strongly and weakly stained cells can coexist side by side. Also cells that, according to morphological criteria, appeared to be inactive still had an apical beta-defensin-1 immunolabeling. We assume that beta-defensin-1, beta-defensin-2 and cathelicidin (LL-37) work together with other antimicrobial peptides and proteins to create a defensive barrier against microbial invasion at the ocular surface.     

Does the occurrence of adverse life events in patients with breast cancer lead to a change in illness behaviour?

Goals of work  It was examined whether life-changing events may lead to changes of illness behaviour in women prior to breast cancer diagnosis. We considered the delay in three different aspects: date of breast self-examination, routine visits at the doctor, and finally changes in the length of time intervals between the detection of suspicious breast symptoms and the subsequent verification of diagnoses. Materials and methods  The data of 240 patients (age <70 years) with a first manifestation of breast cancer were used for analysis. Life events were assessed by means of a semi-structured interview as proposed by Brown and Harris and classified according to a system proposed by Brugha et al., the List of Threatening Experiences (LTE). All analyses were performed by means of Cox’s proportional hazard regression. Main results  Women with stressful events went to the doctor earlier than those without events. The date of breast self-examination remained unchanged after the occurrence of events. Women who had discovered suspicious breast symptoms delayed the subsequent visit at the doctor if they had experienced two serious events within this period. The occurrence of life events may have effects on illness behaviour, but into different directions. Conclusion  In the majority of cases, event-related delays were shorter than those reported to aggravate the prognosis of breast cancer.     

Stimulation-Dependent Effect of Antiepileptic Drugs in Amygdala Kindled Rats on Both Seizure Score and Duration of Afterdischarges

Abstract: The ED₅₀ for abolition of generalized seizures and reduction of afterdischarges to 20% of the control duration was determined in kindled rats for phenobarbital, carbamazepine, phenytoin, valproic acid, clonazepam, and diazepam, both at a stimulation intensity of 200 μA and at 10 μA above the threshold for generalized seizures (threshold stimulation). Phenobarbital, carbamazepine, and valproic acid acted in a stimulus-dependent manner, i.e. the ED₅₀ was higher at 200 μA than at threshold stimulation. Phenytoin had the same ED₅₀ irrespective of the stimulus intensity. Generalized seizures and afterdischarges were suppressed by the same doses of the drugs mentioned. The benzodiazepines, clonazepam and diazepam, had a differential effect: they suppressed generalized seizures at low doses, whereas afterdischarges were only suppressed incompletely at relatively high doses. The ED₅₀ of both benzodiazepines was independent of stimulus intensity. In order to avoid erroneous conclusions a standardization of kindling parameters, especially stimulation intensity, is proposed when drug effects are to be compared.     

Excessive infant crying and intuitive parental care: Buffering support and its failures in parent-infant interaction

Behavioral microanalyses of early parent-infant communication have revealed nonconscious adaptive behaviors in the parent which function as effective soothing interventions and may prevent excessive infant crying. Elicited by the infant's subtle non-cry signals, parental nonconscious interventions facilitate the infant's postpartum physiological, affective, and integrative adaptation, and support non-cry communication and speech acquisition.

Reciprocal interrelations between factors of infant crying and intuitive forms of parental interventions are represented in a psychobiological interactional model predicting twofold outcomes. In one direction, parental interventions may function as a protective buffer which mitigates the effects of factors causing irritability, unexplained fussiness, and abnormal crying in infants until compensatory improvements are gradually achieved. In the other direction, intuitive parental caregiving may fail due to primary unfavorable predispositions and#shor secondarily due to the effects of infant crying. Such failure may exacerbate infant crying and start a vicious circle of decompensation leading to syndromes of neglect or abuse. The model offers a basis for both further empirical studies, and clinical improvements of diagnosis, prevention, and therapy of interactional failures.     

Roundtable Discussion: Early Labor: What's the Problem?

In places where hospital birth is the norm, one of the major contemporary challenges to the organization of intrapartum care is posed by women who are not in established labor. In the United Kingdom, these women have been given a special name, “Category X,” and they can account for a substantial percentage of admissions 1 . These women are not deemed to be in need of hospital care, but the women themselves may feel otherwise as they struggle to understand the sensations they are experiencing. Until relatively recently, little research effort was expended on early and latent phase labor, reflecting, perhaps, the assumption that it is just a gentle and relatively straightforward preamble to the “real thing” that can easily be dealt with by keeping mobile, leaning over furniture, or doing the ironing. Because early labor is not seen as needing a health professional's input, the message is that it is unimportant. However, emerging evidence is challenging that view. Four large randomized controlled trials have recently evaluated interventions related to early labor care 2 - 5 , stimulated by concerns that included repeated visits to the labor ward and the impact of early admission with the potential for a cascade of interventions. These trials, and other research reporting women's own perspectives on labor onset, reflect growing awareness that this stage of labor merits consideration in its own right. An International Early Labor Research Group has formed who will develop the evidence base in this important part of childbearing. The group represents varied disciplines including midwifery, psychology, epidemiology, antenatal education, and service user representatives. Members of this group are among those who have contributed to this Roundtable Discussion. The contributions draw attention to the complexities of early labor and its importance for childbearing women, their caregivers and companions. We might reasonably hypothesize that a woman's experience of early labor sets the scene for what follows, and it is clear that this is an area worthy of considerable further research. The Roundtable Discussion project and the Preface were prepared by Josephine M. Green and Helen Spiby.     

Does heterogeneity of pimonidazole labelling correspond to the heterogeneity of radiation-response of FaDu human squamous cell carcinoma?

BACKGROUND AND PURPOSE: Pimonidazole is a marker for hypoxic cells which are radioresistant and thereby important for the outcome of radiotherapy. The present study evaluates heterogeneity in pimonidazole binding within and between tumours and relates the results to the heterogeneity of radiation response in the same tumour cell line. MATERIALS AND METHODS: FaDu, a poorly differentiated human squamous cell carcinoma line, was transplanted subcutaneously into the right hind-leg of NMRI nude mice. Tumours were irradiated with graded single doses either under ambient or clamped blood flow conditions and local tumour control was evaluated after 120 days. Complete dose-response curves for local tumour control were generated and the slope, a measure of heterogeneity of radiation response, was determined. In parallel, 12 unirradiated tumours were examined histologically. Seven serial 10 microm cross-sections per tumour were evaluated using fluorescence microscopy and computerised image analysis to determine the pimonidazole hypoxic fraction (pHF). Heterogeneity in pHF was quantified by its coefficient of variation (CV). Poisson-based model calculations considering the intertumoural heterogeneity of pHF were performed and the slopes of the predicted and the observed dose-response curves were compared. RESULTS: The mean pHF was 11% [CV 50%] when one central section per tumour was evaluated. Measurements of multiple sections per tumour resulted in a mean pHF of 12% [CV 46%] (P=0.7). Intertumoural heterogeneity in pHF was more pronounced than heterogeneity in individual tumours by a factor of 2. Model calculations based on the variability in pHF resulted in similar slopes of the dose-response curve for local tumour control in comparison with the observed slope when the heterogeneity in an unknown and arbitrarily chosen additional radiobiologically relevant parameter, in this example clonogen density, was taken into account. CONCLUSIONS: While the average pimonidazole hypoxic fraction in FaDu tumours corresponds well to the radiobiological hypoxic fraction, the variability of pHF in FaDu tumours was not sufficient to explain the heterogeneity of radiation response in the same tumour line. Information on at least one additional parameter is expected to substantially enhance the predictive power of histological markers of tumour hypoxia.