Kinematic characteristics of the voluntary cyclic trunk movements in patients at the early stage of Parkinson's disease

Patients with the initial stage of Parkinson disease (PD) and matched controls performed repetitive bendings and turnings in standing position. Tasks included trunk movements in each of the anatomical planes: sagittal, frontal and axial. Electromagnetic system Flock of Birds was used for movement registration. Sensors were fixed at different segments of subject's body. Joint angles in the ankle, hip and torso as well as coordinates of the center of pressure served as output parameters. The amplitudes of joint angles were found to be lower in PD patients. Performance of the axial rotation revealed most pronounced differences. Thus, the amplitudes of joint angles of trunk movements in different anatomical planes reliably discriminate between PD patients and healthy subjects.     

Regulation of motor behaviour

The review is devoted to analysis of the basic links of motor behavior control systems: sensorimotor cortex, cerebellum, a red nucleus and striatum. The organization and communications of these structures and their participation in learning and memory processes are described. The synaptic neurotransmitter and nonsynaptic neuromodulatory systems innervating these structures are also described. Hierarchical synaptic networks are formed by GABA and glutamatergic systems. The nonsynaptic dopaminergic system innervates both of these structures, but carries out a modulatory function. The mesocorticolimbic dopaminergic system induces an emotional and motivational state - processes of reinforcement, and participates in realization of purposeful behavior. The nigrostriatal dopaminergic system, through triggering an endocellular signal and the processes ofphosphorylation and dephosphorylation modulates activity ofGABA and glutamatergic receptors ofdorsal striatum spiny neurons and adapted thalamocortical networks.     

Targeting abnormal DNA repair in therapy-resistant breast cancers

Although hereditary breast cancers have defects in the DNA damage response that result in genomic instability, DNA repair abnormalities in sporadic breast cancers have not been extensively characterized. Recently, we showed that, relative to nontumorigenic breast epithelial MCF10A cells, estrogen receptor-positive (ER+) MCF7 breast cancer cells and progesterone receptor-positive (PR+) MCF7 breast cancer cells have reduced steady-state levels of DNA ligase IV, a component of the major DNA-protein kinase (PK)-dependent nonhomologous end joining (NHEJ) pathway, whereas the steady-state level of DNA ligase IIIα, a component of the highly error-prone alternative NHEJ (ALT NHEJ) pathway, is increased. Here, we show that tamoxifen- and aromatase-resistant derivatives of MCF7 cells and ER(-)/PR(-) cells have even higher steady-state levels of DNA ligase IIIα and increased levels of PARP1, another ALT NHEJ component. This results in increased dependence upon microhomology-mediated ALT NHEJ to repair DNA double-strand breaks (DSB) and the accumulation of chromosomal deletions. Notably, therapy-resistant derivatives of MCF7 cells and ER(-)/PR(-) cells exhibited significantly increased sensitivity to a combination of PARP and DNA ligase III inhibitors that increased the number of DSBs. Biopsies from ER(-)/PR(-) tumors had elevated levels of ALT NHEJ and reduced levels of DNA-PK-dependent NHEJ factors. Thus, our results show that ALT NHEJ is a novel therapeutic target in breast cancers that are resistant to frontline therapies and suggest that changes in NHEJ protein levels may serve as biomarkers to identify tumors that are candidates for this therapeutic approach.     

Angiopoietins have distinct modular domains essential for receptor binding,dimerization and superclustering

Angiopoietins are a recently discovered family of angiogenic factors that interact with the endothelial receptor tyrosine kinase Tie2, either as agonists (angiopoietin-1) or as context-dependent agonists/antagonists (angiopoietin-2). Here we show that angiopoietin-1 has a modular structure unlike any previously characterized growth factor. This modular structure consists of a receptor-binding domain, a dimerization motif and a superclustering motif that forms variable-sized multimers. Genetic engineering of precise multimers of the receptor-binding domain of angiopoietin-1, using surrogate multimerization motifs, reveals that tetramers are the minimal size required for activating endothelial Tie2 receptors. In contrast, engineered dimers can antagonize endothelial Tie2 receptors. Surprisingly, angiopoietin-2 has a modular structure and multimerization state similar to that of angiopoietin-1, and its antagonist activity seems to be a subtle property encoded in its receptor-binding domain.     

Cervicovaginal smear abnormalities in sexually active adolescents. Implications for management

OBJECTIVE: To assess the prevalence and spectrum of Pap smear (PS) abnormalities in sexually active adolescents in comparison to adult women in order to determine whether management of adolescents should differ from that of adults. STUDY DESIGN: Five hundred twenty-four adolescents who had an initial PS at our institution from January to September 1997 were followed for 36 months with repeat PS and/or cervical biopsy. Initial PS results were compared with those of adult women. The chi 2 test was used to calculate the statistical significance of differences between the two groups. The qualified atypical squamous cells of undetermined significance (ASCUS) cytologic diagnosis in adolescents was correlated with follow-up data. RESULTS: The overall prevalence of squamous intraepithelial lesions (SILs) in adolescents was 29% as compared to 23% in adults. Almost all initial squamous lesions were ASCUS and low grade squamous intraepithelial lesion (LSIL); only one case of high grade squamous intraepithelial lesion (HSIL) was detected. On follow-up 18% and 2.4% of adolescents developed LSIL and HSIL, with a LSIL/HSIL ratio of 8/1 as compared to 5/1 in adults. The average time from initial PS to detection of HSIL was 20 months. All patients with HSIL except one had had one or more previous abnormal PSs. The positive predictive values (PPVs) for subsequent dysplasia for ASCUS favor reactive (ASCUS.R), ASCUS not otherwise specified (ASCUS.NOS) and ASCUS favor dysplasia (ASCUS.D) in adolescents were .13, .17 and .31, respectively. ASCUS.NOS (P = .01) and ASCUS.D (P = .007) were strong indicators of dysplasia as compared to ASCUS.R. CONCLUSION: PS abnormalities are more common in sexually active adolescents, with a significantly higher prevalence of LSIL over HSIL as compared to adult women. Given the natural history of HPV infection, we recommend follow-up with cytology rather than colposcopy/biopsy for adolescents with ASCUS and LSIL PSs. Qualification of ASCUS is useful in determining which adolescents are at the highest risk of cervical dysplasia.