Tissue compatibility in regenerating explants from the colonial marine hydroid Hydractinia echinata (Flem.)

Artificially maintained colonies of the colonial marine hydroid Hydractinia echinata are endogenously limited in lateral growth and usually develop in a circular pattern with a closed periderm. Further lateral growth consists of free stolons. Preliminary studies of tissue compatibility in regenerating explants indicate that fusion generally fails to occur if the opposing explants are of differing sex, from different individuals of the same sex, or if peripheral explant contact occurs after free stolons have begun to form. Of the three aforementioned causes of fusion failure, the most important factor appears to be the timing of peripheral explant contact. If regenerating explants contact each other before the endogenous circular growth pattern is achieved, fusion will occur regardless of sex and/or individuality. Incompatibility between explants from the same individual may be because of periderm development inhibition in some instances. However, the failure of free stolon fusion between explants from the same individual suggests the development of “temporal specificity” once the endogenous limit of lateral growth is achieved.     

Development and validation of genetic markers for sex and cannabinoid chemotype in Cannabis sativa L.

Hemp (Cannabis sativa L.) is an emerging dioecious crop grown primarily for grain, fiber, and cannabinoids. There is good evidence for medicinal benefits of the most abundant cannabinoid in hemp, cannabidiol (CBD). For CBD production, female plants producing CBD but not tetrahydrocannabinol (THC) are desired. We developed and validated high‐throughput PACE (PCR Allele Competitive Extension) assays for C. sativa plant sex and cannabinoid chemotype. The sex assay was validated across a wide range of germplasm and resolved male plants from female and monoecious plants. The cannabinoid chemotype assay revealed segregation in hemp populations, and resolved plants producing predominantly THC, predominantly CBD, and roughly equal amounts of THC and CBD. Cultivar populations that were thought to be stabilized for CBD production were found to be segregating phenotypically and genotypically. Many plants predominantly producing CBD accumulated more than the current US legal limit of 0.3% THC by dry weight. These assays and data provide potentially useful tools for breeding and early selection of hemp.     

PACAP and PAC1 Receptor Expression in Human Insulinomas

International Journal of Peptide Research and Therapeutics - Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with widespread occurrence and diverse functions. PACAP...     

Body Position Influences Which Neural Structures Are Recruited by Lumbar Transcutaneous Spinal Cord Stimulation

Transcutaneous stimulation of the human lumbosacral spinal cord is used to evoke spinal reflexes and to neuromodulate altered sensorimotor function following spinal cord injury. Both applications require the reliable stimulation of afferent posterior root fibers. Yet under certain circumstances, efferent anterior root fibers can be co-activated. We hypothesized that body position influences the preferential stimulation of sensory or motor fibers. Stimulus-triggered responses to transcutaneous spinal cord stimulation were recorded using surface-electromyography from quadriceps, hamstrings, tibialis anterior, and triceps surae muscles in 10 individuals with intact nervous systems in the supine, standing and prone positions. Single and paired (30-ms inter-stimulus intervals) biphasic stimulation pulses were applied through surface electrodes placed on the skin between the T11 and T12 inter-spinous processes referenced to electrodes on the abdomen. The paired stimulation was applied to evaluate the origin of the evoked electromyographic response; trans-synaptic responses would be suppressed whereas direct efferent responses would almost retain their amplitude. We found that responses to the second stimulus were decreased to 14%±5% of the amplitude of the response to the initial pulse in the supine position across muscles, to 30%±5% in the standing, and to only 80%±5% in the prone position. Response thresholds were lowest during standing and highest in the prone position and response amplitudes were largest in the supine and smallest in the prone position. The responses obtained in the supine and standing positions likely resulted from selective stimulation of sensory fibers while concomitant motor-fiber stimulation occurred in the prone position. We assume that changes of root-fiber paths within the generated electric field when in the prone position increase the stimulation thresholds of posterior above those of anterior root fibers. Thus, we recommend conducting spinal reflex or neuromodulation studies with subjects lying supine or in an upright position, as in standing or stepping.     

Stabilized dried blood spot collection

During the collection phase of the dried blood spot method, practitioners need to ensure that there is no smearing of the blood sample on the filter paper or else readings from it will be invalid. This can be difficult to accomplish in the field if there is relative motion between the site of blood discharge on the finger and the filter paper. In this article, a gyroscope stabilization method is introduced and demonstrated to provide consistent and improved dried blood spot collection within a circular guide region notwithstanding the presence of rocking.     

Sensitive detection of GFP utilizing tyramide signal amplification to overcome gene silencing

The green fluorescent protein (GFP) is among the most commonly used expression markers in biology. GFP-tagged cells have played a particularly important role in studies of cell lineage. Sensitive detection of GFP is crucially important for such studies to be successful, and problems with detection may account for discrepancies in the literature regarding the possible fate choices of stem cells. Here we describe a very sensitive technique for visualization of GFP. Using it we can detect about 90% of cells of donor origin while we could only see about 50% of these cells when we employ the methods that are in general use in other laboratories. In addition, we provide evidence that some cells permanently silence GFP expression. In the case of the progeny of bone marrow stem cells, it appears that the more distantly related they are to their precursors, the more likely it is that they will turn off the lineage marker.     

RAGE, diabetes, and the nervous system

Longstanding diabetes mellitus targets kidney, retina, and blood vessels, but its impact upon the nervous system is another important source of disability. Diabetic peripheral neuropathy is a serious complication of inadequately treated diabetes leading to sensory loss, intractable neuropathic pain, loss of distal leg muscles, and impairment of balance and gait. Diabetes has been implicated as a cause of brain atrophy, white matter abnormalities, and cognitive impairment and a risk factor for dementia. Recent studies have incriminated advanced glycation end products (AGEs) and their receptor (RAGE) in the pathogenesis of diabetic nervous system complications. The availability of RAGE knockout mice and a competitive decoy for AGEs, soluble RAGE (sRAGE), has advanced our knowledge of the RAGE-mediated signalling pathways within the nervous system. They also provide hope for a future novel intervention for the prevention of diabetes-associated neurological complications. This review will discuss current knowledge of diabetes- and RAGE-mediated neurodegeneration, involving the distal-most level of epidermal nerve fibers in skin, major peripheral nerve trunks, dorsal root ganglia, spinal cord, and brain.