Daily running promotes spatial learning and memory in rats.

Previous studies on exercise have shown that physical activity improves learning and memory. Present study was performed to determine the effects of acute, chronic and continuous exercise with different periods on spatial learning and memory recorded as the latency and length of swim path in the Morris water maze testing in subsequent 8 days. Four rat groups were included as follows: (1) group C, controls which did not exercise; (2) group A, 30 days treadmill running before and 8 days during the Morris water maze testing period; (3) group B, 30 days exercise before the Morris water maze testing period only; (4) group D, 8 days exercise only during the Morris water maze testing period. The results showed that chronic (30 days) and continuous (during 8 days of Morris water maze testing days) treadmill training produced a significant enhancement in spatial learning and memory which was indicated by decreases in path length and latency to reach the platform in the Morris water maze test (p<0.05). The benefits in these tests were lost in 3 days, if the daily running session was abandoned. In group D with acute treadmill running (8 days exercise only) the difference between the group A disappeared in 1 week and benefit seemed to be obtained in comparison with the controls without running program. In conclusion the chronic and daily running exercises promoted learning and memory in Morris water maze, but the benefits were lost in few days without daily running sessions in adult rats.     

Clinical and histopathologic studies of two families with lattice corneal dystrophy and familial systemic amyloidosis (Meretoja syndrome)

Lattice corneal dystrophy associated with familial systemic amyloidosis (Meretoja syndrome) has rarely been described other than in patients of Finnish origin. The authors report two North American patients with this disease who manifest blepharochalasis, lattice corneal dystrophy, open-angle glaucoma, and cranial neuropathy. In one patient, a corneal intraepithelial and subepithelial pseudodendrite was managed by superficial keratectomy, and this same patient benefited from surgical brow suspension for facial muscular weakness. In the second patient, penetrating keratoplasty was complicated by a neurotrophic persistent epithelial defect. Corneal tissue from both superficial keratectomy and penetrating keratoplasty exhibited ultrastructurally characteristic amyloid filaments and associated elastoid material. Transmission electron microscopy of conjunctiva and skin biopsies similarly revealed amyloid deposits associated with most basement membranes, the perineurium and endoneurium of most peripheral nerves, and the intima and media of arteries. By immunoperoxidase staining, the corneal amyloid deposits were positive for the amyloid P-component protein but negative for the nonimmunoglobulin amyloid A protein and prealbumin. Serum prealbumin and amyloid A related protein were normal.     

Daily Running Promotes Spatial Learning and Memory in Rats

Previous studies have shown that physical activity improves learning and memory. Present study was performed to determine the effects of acute, chronic and continuous exercise with different periods on spatial learning and memory recorded as the latency and length of swim path in the Morris water maze testing in subsequent 8 days. Four rat groups were included as follows: 1- Group C (controls which did not exercise). 2- Group A (30 days treadmill running before and 8 days during the Morris water maze testing period). 3- Group B (30 days exercise before the Morris water maze testing period only) and 4- Group D (8 days exercise only during the Morris water maze testing period). The results showed that chronic (30 days) and continuous (during 8 days of Morris water maze testing days) treadmill training produced a significant enhancement in spatial learning and memory which was indicated by decreases in path length and latency to reach the platform in the Morris water maze test (p < 0.05). The benefits in these tests were lost in three days, if the daily running session was abandoned. In group D with acute treadmill running (8 days exercise only) the difference between the Group A disappeared in one week and benefit seemed to be obtained in comparison with the controls without running program. In conclusion the chronic and daily running exercises promoted learning and memory in Morris water maze, but the benefits were lost in few days without daily running sessions in adult rats.

Key points

• Daily running influence on spatial memory.
• The velocity of learning can be influenced by running activity.
• Path length is important parameter for measuring the speed of learning.

Key words: Exercise, spatial memory, hippocampus, Morris water maze     

Pathologic changes in the exorbital lacrimal gland of the vitamin A-deficient rat

Histologic changes in lacrimal glands of vitamin A-deficient (A-) and pair-fed control rats were compared. In A- lacrimal glands, secretory granules were strikingly diminished, and rough endoplasmic reticulum appeared somewhat atrophic. Nuclei of acinar cells were hyperchromatic and pleomorphic. Using alcian blue-PAS, no positive staining was present in acini of A- lacrimal glands, whereas in controls apical portions of acini were intensely stained. Thus, lacrimal tissues of A- rats were thought to be poorly differentiated as a glandular epithelium. When A- rats were supplemented with retinyl acetate, secretory granules reappeared, rough endoplasmic reticulum cisternae greatly dilated, and mitochondria proliferated, indicating accelerated secretory activity. Resupply of vitamin A can induce glandular differentiation in A- lacrimal tissues. Tear volume was not decreased in A- rats compared with pair-fed controls. Regression of secretory organelles in A- lacrimal tissues may lead to a decrease in protein and mucoprotein secretion and subsequent changes in tear composition.     

Polymorphonuclear neutrophils delay corneal epithelial wound healing in vitro

Using an in vitro system for measuring epithelial wound healing, we studied the effect of polymorphonuclear neutrophils (PMNs) and PMN lysate on rat corneal epithelial wound healing. After 22 hr of organ culture, epithelial defects that were originally 3 mm in diameter (7.06 mm2) measured 0.41 mm2 (range, 0.17-0.72 mm2) in control rat corneas, 2.11 mm2 (range, 0.81-3.91 mm2) in corneas incubated in medium containing 5 X 10(6) PMN/ml, and 2.49 mm2 (range, 2.21-2.76 mm2) in corneas incubated with lysate obtained from an equivalent number of PMNs. Scanning and transmission electron microscopy showed similar morphology in the three groups. PMNs selectively adhered to the leading edge of the wound in corneas incubated with PMNs. These data indicate that PMNs and PMN lysate significantly slow corneal epithelial wound healing in vitro.     

In vitro toxicity of gentamicin to corneal epithelial cells

We report morphologic and viability changes in the rabbit corneal epithelium exposed in vitro to gentamicin sulfate. Rabbit corneal epithelial cells (3 x 10(5)) were seeded in replicate 24-well plates at their first in vitro passage, and gentamicin in concentrations of 0, 50, 250, 500, 1,000, or 5,000 micrograms/ml was added to the tissue culture medium beginning 7 days after subculture. By phase contrast microscopy, changes in cell morphologic appearance, particularly increased cytoplasmic granularity, were observed in the 5,000-micrograms/ml groups as early as 24 h after introduction of the drug. At 48 h, similar findings were observed in the 250-micrograms/ml group and at all higher concentrations. The cytoplasmic granularity was not noted in the 0- or 50-micrograms/ml groups. By electron microscopy, these observations correlated with ultrastructural findings of increased accumulations of intralysosomal bodies beginning in the 250-micrograms/ml group after 48 h of exposure to gentamicin. Furthermore, a statistically significant difference (p = 0.001) was demonstrated between the total number of viable cells in the low-dose group (50-micrograms/ml) and the high-dose groups (greater than or equal to 250-micrograms/ml) for exposure periods of 48 h or more. These findings demonstrate aminoglycoside toxicity to corneal epithelial cells in vitro similar to that seen in the human kidney and conjunctiva.     

Treadmill running reverses retention deficit induced by morphine

Human and animal studies have suggested that exercise has benefits overall health and cognitive function. The aim of this study was to investigate the effect of treadmill running on passive avoidance learning and memory deficit in morphine-treated rats. The passive avoidance learning was measured in different time intervals (1, 2 and 24 h as well as 1 week and 1 month). Four groups of rats were included as follows: control, morphine-treated, exercised-saline and exercised-morphine-treated group. The electrical foot shock and treadmill training (2 h at a speed of 5 m/min for 10 days) were applied for all the groups. The data obtained was analyzed using unpaired Students t-test and ANOVA test with group as the independent variable, and performance in each session (avoidances and crossings) as the dependent variables. The results show that the total time staying in dark box was decreased in exercised-saline and exercised-morphine-treated rats by treadmill running (P<0.05). The avoidance learning was significantly reduced in morphine-treated group as indicated by the increased total time of staying in the dark box compared with the control group (P<0.05). We could conclude that exercise increased the delay time of entry to the dark electrical foot shock box, suggesting that morphine impaired the short-term memory and learning and this was reversed by the treadmill running.     

Morphologic Effect of Hyperosmolarity on Rabbit Corneal Epithelium

The morphologic effect of hyperosmolarity, equivalent to that seen in the tear film of patients with keratoconjunctivitis sicca (KCS), on rabbit corneal epithelium in vitro and in vivo was studied. In the in vitro studies, corneal epithelium was grown in explant cultures. Control tissue was cultured in a 307 mOsm/L medium. Epithelium cultured in the 333, 361 and 363 mOsm/L media showed decreased intercellular connections, blunting and loss of microplicae, disruptions in cell membranes and cellular swelling with decreased cytoplasmic density. In in vivo studies, corneas bathed in balanced salt solutions (BSS) concentrated to 330, 360, or 407 mOsm/L showed increased cell desquamation, and the cell changes observed at similiar osmolarities in the in vitro studies. The tear film osmolarities observed in KCS are sufficient to cause the corneal epithelial changes seen in patients with this disease.     

Atrial septal defect closure in the elderly is associated with excellent quality of life, functional improvement, and ventricular remodelling

Background

While atrial septal defect (ASD) closure is known to improve morbidity and mortality in children and adults, data are only beginning to emerge about its role in elderly cohorts. The goals of this study were to compare outcomes after device or surgical closure of ASDs in the elderly, and to quantitatively assess quality of life.

Methods

Patients > 60 years old who underwent ASD repair were studied. Functional status, arrhythmia burden, biventricular size and function were compared before and after ASD closure. Quality of life after ASD closure was assessed with the RAND SF-36 instrument.

Results

Sixty-seven patients, mean age of 68 years (range 60-86 years), were followed for 3.3 years. Nineteen percent underwent surgical closure and 81% underwent device closure. Major complication rates were 23% and 7% respectively with no procedure- related deaths. After surgical and device closure, quality of life was comparable to age-matched healthy controls, right ventricular end-diastolic dimension decreased by 10 mm (P < 0.001), left ventricular end-diastolic dimension increased by 4 mm (P = 0.001), biventricular function improved (right ventricular, P < 0.001; left ventricular, P = 0.007) and New York Heart Association class improved (P < 0.001). Prevalence of atrial arrhythmias however, was unchanged. Beneficial effects were similar for patients treated surgically or with device closure.

Conclusions

Given the favorable structural, functional, and quality of life outcomes after ASD closure in the elderly, advanced age alone should not be a contraindication to recommending surgical or device closure of an ASD.