BackgroundShedding of the Alzheimer amyloid precursor protein (APP) ectodomain can be accelerated by phorbol esters, compounds that act via protein kinase C (PKC) or through unconventional phorbol-binding proteins such as Munc13-1. We have previously demonstrated that application of phorbol esters or purified PKC potentiates budding of APP-bearing secretory vesicles at the trans-Golgi network (TGN) and toward the plasma membrane where APP becomes a substrate for enzymes responsible for shedding, known collectively as α-secretase(s). However, molecular identification of the presumptive "phospho-state-sensitive modulators of ectodomain shedding" (PMES) responsible for regulated shedding has been challenging. Here, we examined the effects on APP ectodomain shedding of four phorbol-sensitive proteins involved in regulation of vesicular membrane trafficking of APP: Munc13-1, Munc18, NSF, and Eve-1.ResultsOverexpression of either phorbol-sensitive wildtype Munc13-1 or phorbol-insensitive Munc13-1 H567K resulted in increased basal APP ectodomain shedding. However, in contrast to the report of Roßner et al (2004), phorbol ester-dependent APP ectodomain shedding from cells overexpressing APP and Munc13-1 wildtype was indistinguishable from that observed following application of phorbol to cells overexpressing APP and Munc13-1 H567K mutant. This pattern of similar effects on basal and stimulated APP shedding was also observed for Munc18 and NSF. Eve-1, an ADAM adaptor protein reported to be essential for PKC-regulated shedding of pro-EGF, was found to play no obvious role in regulated shedding of sAPPα.ConclusionOur results indicate that, in the HEK293 system, Munc13-1, Munc18, NSF, and EVE-1 fail to meet essential criteria for identity as PMES for APP.

Background and Objectives: The current intensity at which a motor response is elicited with an intraneural needle placement has been inadequately studied. We hypothesized that electrical current delivered through an intraneurally placed needle does not always result in an evoked motor response. Our secondary objective was to determine the relationship between electrical current intensity and needle-to-nerve distance. Methods: Twenty pigs were given general anesthesia and the sciatic nerves (SN) were exposed bilaterally. Electrical nerve stimulation was applied 2 cm, 1 cm, 0.5 cm, 0.2 cm, and 0.1 cm away from the SN, transepineurally, and intraneurally (in the subepineurium). Stimulation was started at 2.0 mA and decreased to the minimal current at which visible motor response was obtained. Two blinded observers agreed on the intensity and type of motor response. Specific response of SN was defined as a distal motor response (hoof twitch); nonspecific response was defined as a local muscle twitch (no hoof response). Results: At a distance of 0.5 cm to 2 cm away from the SN, only nonspecific muscle responses were observed. Specific SN responses were obtained starting at 0.1 cm away from the nerve and transepineurally with currents of 0.92 ± 0.33 mA (median 1.00 mA; range 0.24-1.48 mA) and 0.39 ± 0.33 mA (median 0.3 mA; range 0.15-1.4 mA), respectively. With the needle tip positioned intraneurally, specific motor response could be obtained at 0.56 ± 0.54 mA (median 0.3 mA; range 0.08-1.80 mA). Five (12.5%) intraneurally positioned needles only elicited a specific motor response at 0.8-1.8 mA. Conclusions: Specific response to nerve stimulation with currents <0.2 mA occurred only when the needle tip was positioned intraneurally. However, motor response could be absent with intraneural needle placement at a current intensity of up to 1.7 mA.

Craniofacial area is apart of the human body which undergoes the greatest changes during development and is characterized by uneven growth. External and internal factors affect the growth and development of craniofacial structures. They are responsible for the occurrence of specific craniofacial characteristics in different races or populations within the same race. The present study investigates the possible differences of the basic head and face shapes between the Croatian and Syrian populations. The sample included 400 subjects of both sexes aged 18-24 years and was divided into a Croatian and a Syrian group with 200 subjects each. Six variables defined according to Martin and Saller were measured by standard anthropometric instruments. The results of the study demonstrated statistically significant differences between our subjects in all variables except face width. The dolichocephalic head type and the mesoprosopic face type were predominant in the Croatian population, while the brachycephalic head type and the euryprosopic face type dominated in the Syrian population.