The discovery of actin: “to see what everyone else has seen,and to think what nobody has thought”*

Journal of Muscle Research and Cell Motility - Actin is among the most highly abundant and ubiquitous proteins in eukaryotic cells. The structure, dynamics and functional diversity of actin have...     

Prevalence of impacted permanent upper canine and its treatment in 11-18-year-old orthodontic patients

Data of literature show very high prevalence of impacted upper permanent canine. The aim of the present study was to evaluate prevalence of retentioned or impacted upper permanent canines and to present their therapy. Data on 11-18-year-old children presented for treatment at the Department of Dentistry for Children and Orthodontics in Budapest over a period of 10 years (between 1990 and 2000) were analysed. OP X-ray films of 1858 children and adolescents--1102 female and 756 male--were examined and the data of anamnesis and the administered therapy were considered. Results revealed 101 cases of impacted cuspids, the male:female ratio was 46:55. Considering the totality of administered treatment methods, both surgical exposure and orthodontic treatment of the affected canines were needed in a high rate, i.e. 96.92% of the analysed cases. In 40.91% of the cases extraction of the correspondent upper first premolar was needed. Following the premolar extraction spontaneous occlusions of the impacted canine was established in 3.03%. Authors present the complex therapy of one case of palatally impacted upper permanent canine.     

Effect of induction chemotherapy on changes of laminin and syndecan expression in oral squamous cell carcinomas: a prospective, randomized, clinicopathologic and immunohistochemical study

Sixty patients with tumors of the floor of the mouth or of the tongue (T2N0-1-2M0) were randomized into three treatment groups. The first two groups participated in low-dose inductive chemotherapy, surgery, and then radiotherapy, whereas the third control group underwent only surgery and radiotherapy. In all three groups, studies were made of the stage, grade, sex, localization, extents of expression of the pretreatment laminin and syndecan-1 and the cancer specific survival rate, and the correlations among these. The response to neoadjuvant chemotherapy was assessed by means of a method that we developed, involving measurement of the degree of histologic regression observed in response to chemotherapy. Immunohistochemical methods were applied to investigate the changes in degree of expression of laminin and syndecan-1 in response to the medication and their correlations with the survival. As concerns the overall tumorfree survival rate, a significant difference was not found between the two chemotherapeutic groups. However, there was a significant difference between the survival indices of those who participated in cytostatic treatment (70%) and the control group (40%). In the clinical and immunohistochemical examinations, the initial laminin and syndecan-1 levels obtained from biopsy samples could be used as prognostic factors. Our model measuring the extent of histologic regression clearly demonstrated that the survival indices of the patients who responded to the neoadjuvant cytostatic treatment with adequate tissue regression were better than those of the patients who responded to the treatment to only a decreased extent or not at all. The changes in the expressions of laminin and syndecan-1 in response to cystostatic treatment proved to be important predictive factors. The increase or stagnation of these clearly forecast a good prognosis, whereas their decrease was a definite indication of poor prognosis.     

Effective connectivity in target stimulus processing: a dynamic causal modeling study of visual oddball task

PURPOSE: To investigate the fundamental connectivity architecture of neural structures involved in the goal-directed processing of target events. METHODS: Twenty healthy volunteers underwent event-related functional magnetic resonance imaging (fMRI) while performing a standard oddball task. In the task, two types of visual stimuli - rare (target) and frequent - were randomly presented, and subjects were instructed to mentally count the target stimuli. Dynamic causal modeling (DCM), in combination with Bayes factors was used to compare competing neurophysiological models with different intrinsic connectivity structures and input regions within the network of brain regions underlying target stimulus processing. RESULTS: Conventional analysis of fMRI data revealed significantly greater activation in response to the target stimuli (in comparison to the frequent stimuli) in several brain regions, including the intraparietal sulci and supramarginal gyri, the anterior and posterior cingulate gyri, the inferior and middle frontal gyri, the superior temporal sulcus, the precuneus/cuneus, and the subcortical grey matter (caudate and thalamus). The most extensive cortical activations were found in the right intraparietal sulcus (IPS), the anterior cingulate cortex (ACC), and the right lateral prefrontal cortex (PFC). These three regions were entered into the DCM. A comparison on a group level revealed that the dynamic causal models in which the ACC and alternatively the IPS served as input regions were superior to a model in which the PFC was assumed to receive external inputs. No significant difference was observed between the fully connected models with ACC and IPS as input regions. Subsequent analysis of the intrinsic connectivity within two investigated models (IPS and ACC) disclosed significant parallel forward connections from the IPS to the frontal areas and from the ACC to the PFC and the IPS. CONCLUSION: Our findings indicate that during target stimulus processing there is a bidirectional frontoparietal information flow, very likely reflecting parallel activation of two distinct but partially overlapping attentional or attentional/event-encoding neural systems. Additionally, a simple hierarchy within the right frontal lobe is suggested with the ACC exerting influence over the PFC.     

Role of Matrix Metalloproteinases in Skin Ageing

Matrix metalloproteinases are a family of ubiquitous endopeptidases playing a role in many different physiological and pathological processes in the skin. They are also involved in cutaneous ageing. This review summarizes the features and regulation of these enzymes and presents an overview of the molecular mechanisms of both intrinsic and extrinsic skin ageing presents. The role of matrix metalloproteinases in skin ageing is discussed in detail.     

MEROPENEM IN THE TREATMENT OF FEBRILE NEUTROPENIC CHILDREN

The aim of this retrospective study was to evaluate the clinical effectiveness of meropenem in immunocompromised children. Between January 1998 and December 2002 in the hemato-oncological units of our hospital meropenem was used in 87 febrile events diagnosed in 55 patients, and 328 bacterial cultures were evaluated. Microorganisms were detected and identified in 64 of the 328 hemocultures; there was a predominance of gram-positive strains (67%). In 49.4% the infection was documented microbiologically. In 16 additional cases the infection was proven clinically and 32.2% of the episodes were considered to be fever of unknown origin. The success rate of the meropenem therapy—excluding the proven fungal or coagulase-negative Staphylococcus infections—was 72.9% and for the whole cohort 49.4%. The results demonstrate that meropenem is effective and well-tolerated when used for the treatment of neutropenic cancer children.     

Childhood Lichen Planus Pemphigoides: Report of Two Cases Treated Successfully with Systemic Glucocorticoids and Dapsone

We describe two boys, ages 8 and 7 years, who developed lichen planus pemphigoides. In one of the boys, a henna tattoo probably triggered the disease. Therapy with systemic glucocorticoids and dapsone was successful.     

Lipotoxicity in the liver

Obesity due to excessive food intake and the lack of physical activity is becoming one of the most serious public health problems of the 21^st century. With the increasing prevalence of obesity, non-alcoholic fatty liver disease is also emerging as a pandemic. While previously this pathophysiological condition was mainly attributed to triglyceride accumulation in hepatocytes, recent data show that the development of oxidative stress, lipid peroxidation, cell death, inflammation and fibrosis are mostly due to accumulation of fatty acids, and the altered composition of membrane phospholipids. In fact, triglyceride accumulation might play a protective role, and the higher toxicity of saturated or trans fatty acids seems to be the consequence of a blockade in triglyceride synthesis. Increased membrane saturation can profoundly disturb cellular homeostasis by impairing the function of membrane receptors, channels and transporters. However, it also induces endoplasmic reticulum stress via novel sensing mechanisms of the organelle’s stress receptors. The triggered signaling pathways in turn largely contribute to the development of insulin resistance and apoptosis. These findings have substantiated the lipotoxic liver injury hypothesis for the pathomechanism of hepatosteatosis. This minireview focuses on the metabolic and redox aspects of lipotoxicity and lipoapoptosis, with special regards on the involvement of endoplasmic reticulum stress responses.