Organic solvent-induced proximal tubular cell apoptosis via caspase-9 activation

Long-term exposure to solvents is associated with apoptosis, which is implicated in the development and progression of tubulo-interstitial fibrosis and chronic renal failure. In our previous study, we demonstrated that toluene and p-xylene as the most commonly used organic solvents induced proximal tubular cells apoptosis. This study was conducted to assess the apoptotic pathway of toluene and p-xylene induced proximal tubular apoptosis. This was assessed by measuring the caspase-9 activity LLC-PK1 cells exposed to both compounds. A model of proximal tubular cell (LLC-PK1) cytotoxicity exposed to 1 mM of either p-xylene or toluene was compared to untreated control for caspase-9 activity and Bax/Bcl-2 protein level. Furthermore, DNA fragmentation in the presence of caspase-9 inhibitor (Z-LEHD-FMK) in a dose-dependent manner was assessed. Both compounds induced caspase-9 activity, which was accompanied by up-regulation of Bax, whereas Bcl-2 level did not change. DNA fragmentation induced by both solvents was inhibited by caspase-9 inhibitor in dose-dependent manner. This data suggest that p-xylene or toluene induces nephrotoxicity via mitochondrial caspase-9 pathway. This mechanism involves up-regulation of the apoptotic protein, Bax.     

Evaluation of quality of life of patients with oral squamous cell carcinoma. Comparison of two treatment protocols in a prospective study

BACKGROUND AND PURPOSE: In recent years, various therapeutic concepts have been developed for treating oral cancer, these include preoperative simultaneous "neoadjuvant" radio-chemotherapy and one-stage-surgery with tumour ablation and reconstruction. When considering long-term survival, there is substantial evidence that the neoadjuvant therapy is superior to the primary surgical approach with postoperative radiation. Both treatment concepts, however, have a strong impact on the quality of life. PATIENTS AND METHODS: This study prospectively evaluates and compares quality of life in 53 patients with oral cancer treated according to a neoadjuvant concept or primarily surgically, using the questionnaires QLQ C-30 and H and N35 by the EORTC. RESULTS: Initially both groups showed a marked reduction in the quality of life. Despite a clear improvement in the first postoperative year baseline values were not reached in most of the scores. Specific long-lasting impairments in the symptom scales concerning oral functions were found in both treatment arms. In the neoadjuvant therapy group, however, especially global health and the emotional status were reduced to a higher degree than in the other group. This was particularly noticeable in the early treatment phase. CONCLUSIONS: Following an initial deterioration of quality-of-life after 3 months a gradual improvement of physical and psychological function was observed in the course of the first post-treatment year in both groups. Severe side effects can be observed. These side effects vary strongly in their individual expression. Limitations in the quality of life can be justified, if the more aggressive therapy resulted in a better disease free survival.     

Dissociation of hemi-spatial and hemi-motor impairments in a unilateral primate model of Parkinson's disease

Monkeys with unilateral lesions of nigrostriatal dopamine projections were tested on a series of spatial tasks. One task, in which monkeys were required to use one or the other arm to retrieve food rewards from different positions, allowed separate assessment of the use of each arm in each hemi-space in order to distinguish hemi-spatial and hemi-motor impairments. The lesioned monkeys exhibited a persistent neglect of contralesional space when using either arm which could be dissociated from a motor impairment in the contralesional arm alone. Another task allowed free use of either arm across peri-personal space and demonstrated an ipsilesional bias in the monkeys’ self-determined attention (orientation) to a task which they were trying to perform. It is argued that the tendency for monkeys with this lesion to rotate ipsilesionally is due to an ipsilesional deviation of the ‘centre of interest’ (determined by telencephalic circuitry) relative to ‘straight ahead’ (determined by brainstem circuitry). The dopamine projections may contribute to cortico-subcortical circuits which determine the spatial layout of mental representation, attention and intention. The results in this primate model of unilateral Parkinson’s disease (PD) support the view that patients with left-sided Parkinsonian symptoms exhibit a unilateral deficit in spatial mental representation as well as their well-recognised motor symptoms. Patients with bilateral Parkinson’s symptoms may exhibit bilateral deficits in mental representation.     

Development of early motor learning and topical motor skills in a model of cerebellar degeneration

The development of motor learning and topical motor skills has been studied during the first month of life in neurodeficient Lurcher mutant mice derived from C3H strain. The examination of motor functions was conducted using four methods when animals were consecutively placed on: a horizontal wire, a rotating cylinder, a bridge and slanting ladder (on the rotating cylinder and slanting ladder in three different starting positions). A total of 150 animals were used, half being heterozygous mutants (+/Lc), the remaining consisting of their healthy littermates, homozygous wild-type mice (+/+). Some animals of both types were confronted with the tasks in four testing days without practice while the others were trained in all of these methods one time daily at the age of 3, 6, 9, 12, 15, 20, 25 and 30 days. The results of the research are expressed as a percentage of reaching criteria in the trained and untrained mice of both types (+/Lc, +/+), respectively on days 15, 20, 25, and 30. Because of their motor handicap, Lurcher mutants showed significantly worse results than normal mice in almost all of the tests. The most interesting observations of the study were obtained on the rotating cylinder and the slanting ladder tests where mainly untrained mutants were unable to cope promptly with the different starting position and failed. However, in 30-day-old Lurchers the effect of learning was relatively better in some tests when compared with the wild-type of mice. Experiments showed that, in spite of progressive cerebellar degeneration, the ability of motor learning in Lurcher mutants survived to a certain degree. The worsening of results after frequent training in both trained Lurchers and normal mice aged 20 days as compared with untrained ones is discussed within the context of the “overtraining reversal effect” and other possible hypotheses.     

Consequences of forced disuse of the impaired forelimb after unilateral cortical injury

Extreme over-reliance on the impaired forelimb following unilateral lesions of the forelimb representation area of the rat sensorimotor cortex (FL-SMC) leads to exaggeration of injury when overuse is begun during the first week, but not later periods, after injury. Behavioral impairment is partially worsened by the additional tissue loss. In the present study, we show that complete disuse of the impaired forelimb during the first post-operative week renders surviving tissue vulnerable to later overuse of the same limb, in effect extending the window of vulnerability in which use-dependent exaggeration of brain injury can occur. Behavioral recovery is disrupted by complete disuse, but the degree of impairment is variable depending on the nature of the behavioral test employed. Our results uphold the idea that mild rehabilitative training early after injury is beneficial, while either extreme overuse or complete disuse may disrupt functional recovery.     

Walking performance of vestibular-defective patients before and after unilateral vestibular neurotomy

The present study investigated goal-directed linear locomotion in nine Menière’s patients before and after (1 week, 1 and 3 months) a curative unilateral vestibular neurotomy (UVN). Experiments were done using a 3D motion analysis system in subjects walking eyes open (EO) and eyes closed (EC) towards a real or memorized target, respectively. Locomotor pattern (velocity, step length, step frequency and walk ratio) and walking trajectory deviations were evaluated for normal and fast speeds of locomotion and compared to those recorded in 10 healthy subjects. Before UVN, patients showed no walking deviation but gait pattern changes characterized by slower walks compared to the controls, mainly due to step length and step frequency reductions for both visual conditions and locomotion speeds. In the acute stage after UVN, locomotor pattern impairments were significantly accentuated. On the other hand, patients showed strong walking deviations towards the lesioned side with EC. Opposite lateral deviation towards the intact side were observed with EO for normal speed only. Recovery from impaired locomotor pattern was achieved within 1 month for normal speed but remained uncompensated 3 months post-lesion for fast speed particularly in EC condition. Finally, the walking trajectory deviation towards the lesioned side in the dark was maintained up to 3 months after UVN. The results show that central processing of visual and vestibular cues contributes to an accurate locomotor pointing. They argue for an increased weight of visual reference frame on locomotor functions when vestibular function is unilaterally impaired.     

Kinematics of treadmill locomotion in rats conceived, born, and reared in a hypergravity field (2 g). Adaptation to 1 g

The kinematics of treadmill locomotion in rats conceived, born, and raised in a hypergravity environment (HG: 2 g) until the age of 3 months was investigated for 5 weeks after their exposition to earth’s gravity. The locomotor performance of the HG rats (N=7) was compared to that of age-matched control rats (N=8) housed at 1 g for the same period. Kinematic analysis of treadmill locomotion was performed up to 35 days of terrestrial life by an optoelectronic motion analyzer (ELITE system). Results showed that the HG rats exhibited a faster locomotor rhythm (increased number of steps/s), walked closer to the ground, and had a more dorsiflexed foot position. Also, HG rats had shorter steps. The data also highlight a fast adaptation to normal gravity since all the locomotor parameters returned to normal values within 3 weeks. The locomotor modifications may be seen as the persistence of a hypergravity-induced posturo-locomotor adaptation in the centrifuge and/or to more functional changes of sensorimotor systems. Because locomotor performance of HG rats is not severely affected, it is concluded that early development of locomotion processes is highly resistant to gravito-inertial changes.     

Anxiety-related behaviour in C57BL/6 <--> BALB/c chimeric mice

In a previous study on anxiety-related behaviours of the genetically and behaviourally distant inbred mouse strains C57BL/6 and BALB/c using the Elevated plus-maze (EPM) and Open-field (OF) apparatuses, we identified a number of variables, the factorial scores of which were grouped by principal component analysis (PCA) into factors specifically describing each inbred strain [4]. We have now studied the effect of C57BL/6 and BALB/c haploid sets of genes on this behaviour by comparing EPM and OF variables of C57BL/6 and BALB/c versus C57BL/6×BALB/c F1 hybrids (B6CBF1) and chimeric C57BL/6×BALB/c (CHIM) mice. CHIM mice were made by embryo aggregation and the chimerism degree of their brain was inferred from coat black/white distribution. Discriminant analysis of EPM and OF factorial scores of C57BL/6, BALB/c and CHIM mice showed that CHIM mice with an exceeding (≥80%) C57BL/6 or BALB/c coat component had behaviours similar to those of the predominant strain, whereas CHIM mice with intermediate chimerism differed from both inbred strains. Additional MANOVA analysis showed that the anxiety behaviour of CHIM mice with intermediate chimerism was similar to that of B6CBF1 mice as for factors not describing the inbred strains, including a motor activity mostly limited to protected areas, with attempts to approach the anxiogenic areas while processing/storing the external information. We conclude that the balanced presence of both C57BL/6 and BALB/c genetic backgrounds, either when carried by the same cell or by different cells, gives rise to a novel stress coping strategy described by factors different from those of the inbred strains.     

Possible therapy for age-related macular degeneration using human telomerase

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in people over 60 years of age in the US and many other developed countries. Increasingly sophisticated methods for the diagnosis and treatment of macular degeneration are not effective for the majority of patients in whom late stage disease is present at the time of diagnosis. Research to elucidate the changes in RPE cell biology during aging has stimulated interest in preventive and prophylactic therapies for earlier intervention in the degenerative process. In the normal retina, the RPE performs the functions of barrier, macrophage, and neuroprotective cell layer. During aging and in the presence of disease the robustness of each of these functions diminishes. The utility of telomerase-mediated cell and gene therapy to prevent the decline in function of RPE cells during aging is evaluated.     

Vascular change of hippocampal capillary is associated with vascular change of retinal capillary in aging

Vascular deficiency, such as deleterious change of endothelial cells, becomes the prominent feature of hippocampal microvessels during the processes of aging in rodents and it seems to be associated with deficiency of intellectual behavior in aged subjects. The hippocampal microvessels and hippocampal pyramidal neurons form and accumulate intermediates of advanced Maillard reaction (glycation) end products, specifically N()-carboxymethyl lysine (CML) and CML in rodents during the processes of aging. CML facilitates proliferation of endothelial cells in culture. However, further conjugation of CML with the substance(s) seems to occur in the microvessels and pyramidal neurons of hippocampus and it brings about deleterious change of endothelial cells and pyramidal neuron death. This would cause deficiency of recognition and reference memory in rodents during the processes of aging. In man in Alzheimer's disease (AD), one might speculate that formation and accumulation of CML in the hippocampal microvessels initiate the accumulation of amyloid to produce cerebral amyloid angiopathy and it brings about hypoglycemia and hypoxia in the hippocampal pyramidal neurons. Furthermore, formation and accumulation of CML in the hippocampal pyramidal neurons initiate the deposition of neurofibrillary tangles and senile plaques which cause neuronal death. In this way, vascular deficiency of hippocampal microvessels seems to be associated with the demented disease, the atrophic process of the brain and accumulation of amyloid in the brain in man. In terms of vascular deficiency concerns, the vascular change of the retinal capillaries becomes also a prominent feature during the processes of aging and it has a positive correlation with the vascular change of hippocampal capillary. In man during senescence, one might also speculate that vascular change of eye capillaries would become the early market for diagnosis of dementia in AD.