New Surgical Approach To Overcome The Inability Of Injured Mammalian Axons To Grow Within Their Environment

We present a new method for creating conditions conducive to axonal growth in injured optic nerves of adult rabbits. The surgical approach consists of making a cavity in the adult rabbit optic nerve, into which a piece of nitrocellulose soaked with conditioned medium originating from regenerating fish optic nerves is implanted. In addition, daily irradiation (10 days, 5 min, 35 mW) with low energy He-Ne laser is carried out. Such a combined treatment may open a door to neurobiologists and clinicians, hoping to unravel the enigma of mammalian CNS regeneration

A method for a fast and economical in situ collection of pore water in sandy sediments

Marine sediment represents one of the most significant carbon reservoirs. Extraction of pore water from the uppermost 10 cm of the sediment column, just below the sediment-water interface, in coastal environments can be used to assess the rapid chemical changes caused by extensive subsurface biological and chemical reactions. However, owing to relatively large grain size of the sediment in some submerged and shallow coastal environments, sediment and pore water mixes quickly making collection of core samples for pore water extraction extremely difficult. Here, we present a simple method utilizing Rhizons to collect in situ pore water from coastal environments. We conducted both ex situ and in situ experiments, using fluorescein as a tracer, to understand the influence of overlying water during pore water collection through this method. These experiments also allowed us to assess the volume of pore water collected before fluorescein is observed in the samples at different vertical depths within the sediment column. We found that: 1. discarding the initial 2 mL of water minimizes the memory effect, 2. collection of 10 mL of water avoids interference from surrounding pore water and the overlying water column and 3. a vertical resolution of minimum 2 cm could be attained for sediments with grain size of 1 mm and less. We finally present data from two linear transects from different sites in the Gulf of Aqaba. Results from these case studies demonstrate expected patterns of high concentrations of iron and hydrogen sulfide in pore water from the sediment where surface coloration suggested iron and sulfate reduction was dominating, respectively. Both case studies, therefore, independently validated the Rhizon sampler method for collecting pore water in situ from marine sediments in coastal environments

A method for a fast and economical in situ collection of pore water in sandy sediments

Peer reviewed: TrueMarine sediment represents one of the most significant carbon reservoirs. Extraction of pore water from the uppermost 10 cm of the sediment column, just below the sediment-water interface, in coastal environments can be used to assess the rapid chemical changes caused by extensive subsurface biological and chemical reactions. However, owing to relatively large grain size of the sediment in some submerged and shallow coastal environments, sediment and pore water mixes quickly making collection of core samples for pore water extraction extremely difficult. Here, we present a simple method utilizing Rhizons to collect in situ pore water from coastal environments. We conducted both ex situ and in situ experiments, using fluorescein as a tracer, to understand the influence of overlying water during pore water collection through this method. These experiments also allowed us to assess the volume of pore water collected before fluorescein is observed in the samples at different vertical depths within the sediment column. We found that: 1. discarding the initial 2 mL of water minimizes the memory effect, 2. collection of 10 mL of water avoids interference from surrounding pore water and the overlying water column and 3. a vertical resolution of minimum 2 cm could be attained for sediments with grain size of 1 mm and less. We finally present data from two linear transects from different sites in the Gulf of Aqaba. Results from these case studies demonstrate expected patterns of high concentrations of iron and hydrogen sulfide in pore water from the sediment where surface coloration suggested iron and sulfate reduction was dominating, respectively. Both case studies, therefore, independently validated the Rhizon sampler method for collecting pore water in situ from marine sediments in coastal environments

GM1 reduces injury-induced metabolic deficits and degeneration in the rat optic nerve. Invest Ophthalmol Vis Sci

This study demonstrates the earliest reported effects of GM1 treatment on crush-injured axons of the mammalian optic nerve. GM1, administered intraperitoneally immediately after injury, was found to reduce the injury-induced metabolic deficit in nerve activity within 2 hr of injury, as measured by changes in the nicotine-amine adenine dinucleotide redox state. After 4 wk, transmission electron microscopy 1 mm distal to the site of injury revealed a sevenfold increase in axonal survival in GM1-treated compared to untreated injured nerves. These results emphasize the beneficial effect of GM1 on injured optic nerves as well as the correlation between immediate and long-term consequences of the injury. Thus, these results have implications for treating damaged optic nerves. Invest Ophthalmol Vis Sci 33: 3586-3591,1992. Injury of mammalian optic nerves leads to axonal degeneration followed by a loss of retinal ganglion cells, with failure of axonal regrowth. 1 " 3 Initial degeneration of the injured nerve probably results from direct neuronal damage. The associated physiologic and biochemical events that occur in the nerve immediately after injury probably are responsible for the subsequent degeneration, not only of directly injured axons but also of those that escaped the primary damage. These events may contribute significantly to the long-term functional outcome. Moreover, the events that take place at the site of the injury eventually determine the environment encountered by the regrowing axons. 4 " 9 This presumably will influence the ability of the injured nerve to regenerate. 410 The purpose of the present study was to examine the ability of GM1 to attenuate early injury-induced deficits in nerve function and hence the long-term morphologic outcome of injury. Accordingly, we examined the effect of GM1 on early post-traumatic metabolic changes occurring at the injury site as well as on the subsequent axonal morphology. GM1 was chosen based on reports of its effectiveness in vivo at reducing injury-induced behavioral Materials and Methods Metabolic Studies Animal preparation: Animals were used according to the ARVO Resolution on the Use of Animals in Research. Male Sprague-Dawley rats weighing 300-400 g were anesthetized with sodium pentobarbitone (35 mg/kg intraperitoneally). A cannula was introduced into the trachea for artificial ventilation, when required. With the animal's head held in place by a head holder, a lateral canthotomy was performed under a binocular operating microscope and the conjunctiva was incised lateral to the cornea. After the retractor bulbi muscles were separated, the optic nerve was identified and 3-3.5 mm was exposed near the eyeball by blunt dissection. The dura was left intact and care was taken not to injure the nerve. The first part of a light guide holder was inserted under the optic nerve and the nerve was gently eased into the light guide canal. The second part then was fixed in place so that the light guide was located on the surface Downloaded from iovs.arvojournals.org on 07/02/201

Image_1_A method for a fast and economical in situ collection of pore water in sandy sediments.jpeg

Marine sediment represents one of the most significant carbon reservoirs. Extraction of pore water from the uppermost 10 cm of the sediment column, just below the sediment-water interface, in coastal environments can be used to assess the rapid chemical changes caused by extensive subsurface biological and chemical reactions. However, owing to relatively large grain size of the sediment in some shallow coastal environments, sediment and pore water mixes quickly making collection of core samples for pore water extraction extremely difficult. Here, we present a simple method utilizing Rhizons to collect in situ pore water from coastal environments. We conducted both ex situ and in situ experiments, using fluorescein as a tracer, to understand the influence of overlying water during pore water collection through this method. These experiments also allowed us to assess the volume of pore water collected before fluorescein is observed in the samples at different vertical depths within the sediment column. We found that: 1. discarding the initial 2 mL of water minimizes the memory effect, 2. collection of 10 mL of water avoids interference from surrounding pore water and the overlying water column and 3. a vertical resolution of minimum 2 cm could be attained for sediments with grain size of 1 mm and less. We finally present data from two linear transects from different sites in the Gulf of Aqaba. Results from these case studies demonstrate expected patterns of high concentrations of iron and hydrogen sulfide in pore water from the sediment where surface coloration suggested iron and sulfate reduction was dominating, respectively. Both case studies, therefore, independently validated the Rhizon sampler method for collecting pore water in situ from marine sediments in coastal environments.</p