Dopaminergic behaviour in chicken retina and the effect of form deprivation

Purpose: Dopamine (DA)is cinsidered to be a neurotransmitter involved in light-adaptive responses in the retina and has been implicated in the control of the eye growth include by form deprivation vitreal DOPAC was shown to be a good indicator of retinal dopaminergic activity. Methods/Results: Dopaminergic activity was highest during the light, with vitreal DOPAC levels rising within in 3 hof light exposure. Form deperivation attenuated dopaminergic activity, as the rise in vitreal DOPAC levels on light exposure was rediced in form-depeived eyes, compared with control eyes. Conclusion: The lack sustained activation of DA release may explain the role of DA in the control of eye-growth.     

Static balance improvement in elderly after dorsiflexors electrostimulation training

The purpose of the present study was to determine the effect of dorsiflexors ElectroStimulation (ES) training, on postural tasks of increasing difficulty in the elderly. Twenty-one elderly adults were randomly assigned into one of two groups: a Training (TG) and a Control Group (CG). The TG (n=10) performed (4 weeks, 4 s/week, 40 min/session) superimposed (electrically evoked and voluntary activation) isometric dorsiflexions (ankle 100°) while seated. Biphasic, rectangular symmetrical pulses (300 ms, 70 Hz, 20–60 mA) were used to provoke maximal muscle activation. Participants performed three static balance tasks (Normal Quiet Stance, Sharpened Romberg, and One-Legged Stance) during which postural sway was quantified using maximum range and standard deviation of Centre of Pressure displacement (Kistler 9281C, 1,000 Hz). Bipolar surface electrodes were used to record the Electromyographic activity (EMG) of Tibialis Anterior, Medial Gastrocnemius, Rectus Femoris and Semi-Tendineous. Two-dimensional kinematic data were collected (60 Hz) and analyzed using the APAS Motion Analysis software. The body was modeled as a five-segment rigid link system. Isometric dorsiflexion moment/angular position relationship was also established using a Cybex dynamometer. ES training resulted in decreased postural sway (P<0.05), greater ankle muscles EMG activity (P<0.001), greater stability of the ankle joint (P<0.05) and significant changes in mean position of all three joints of the lower limb. In addition, dorsiflexion moment significantly (P<0.001) increased as a result of ES training. It is concluded that dorsiflexors ES training, could reduce postural sway and the use of ankle muscles, more characteristic of young adults, might appear in the elderly as well.     

Immunohistochemical evaluation of TGF-β and extracellular matrix proteins expression in rat squamous cell carcinomas

OBJECTIVE: The aim of this study was to establish a possible association between the degree of differentiation of squamous cell carcinomas (SCC) derived from rat oral tissues treated in vivo with the carcinogen 4NQO, and the expression of TGF-β on epithelial cells and the distribution of extracellular matrix proteins (laminin-collagen type IV).
MATERIALS AND METHODS: A parent tumour showing a spectrum of differentiation was used to establish clonal subpopulations that formed differentiated SCC and undifferentiated (spindle cell phenotype) tumours following transplantation to athymic mice.
RESULTS tmmunohistological findings revealed the absence of TGF-β staining on epithelial cells and extracellular matrix proteins in spindle cell tumours. In contrast, staining of SCC revealed a significant number of TGF-β positive cells and the presence of extracellular matrix proteins.
CONCLUSIONS: The findings suggested that there is a positive correlation between histological differentiation, TGF-β expression and the elaboration of extracellular matrix proteins.     

Distribution of T cells and signs of T-cell activation in the rheumatoid joint: implications for semiquantitative comparative histology

A prerequisite for comparative histology of synovial tissue by means of biopsies is insight into the distribution of a marker under study. This investigation focuses on the variation in the presence of T cells and signs of T-cell activation within the rheumatoid joint. For this purpose, multiple slides from several pieces of synovial tissue from different parts of a joint were stained and scored for the expression of CD3, CD25, HLA-DR, Ki67 and interferon-gamma. The variation in scores for the presence of T cells and markers of activation was more pronounced in slides prepared from different pieces of tissue than in slides from one piece of tissue. Based on multiple analysis of variance, methods are suggested to establish a reliable overall score for the expression of a certain marker within a joint. Following validation, such methods may prove to be useful by allowing semiquantitative histology of synovial tissue for studies on arthritis.