Onthogenic changes in the orientation of the ventricular activation and recovery mean vector in pig

The effect of physical maturation on the ventricular activation and recuperation mean vectors has been analyzed in pigs during a period of time between 1 day and 6 months of age. The results showed that whilst the vectorial magnitude of AQRS on the horizontal plane was not affected by physical maturation, that of the spatial vector (SAQRS) underwent an increase during the period of study. Likewise, it was determined that the ventricular activation front showed an inclination to change its orientation from caudal, sinistral or dextral, to dextrocranial, maintaining the dorsal orientation in all individuals. For the ventricular recuperation mean vector the results showed that its vectorial magnitudes both on the horizontal plane and in space underwent an increase during the 6 months analyzed. As regards the direction of the recuperation front, it was established that, at any age, the preferential orientation is caudal, with a deviation to the left in a high percentage of the 20 day to 3 month old pigs, and ventral in all individuals.     

Effects of age on orientation of attention

The present experiment investigated the influence of age on the magnitude of attentional effects. Subjects were cued to attend to one of two possible stimulus locations horizontally arranged. The instructions were to respond as fast as possible to the occurrence of a visual stimulus, regardless of whether it occurred in a cued or in a non-cued location. When the stimulus occurred in a non-cued location, the subject had to reorient attention to the non-attended, but stimulated, location. Reorienting of attention was directed toward either the left or the right side. The results showed that for the elders, time for reorienting was longer than for younger subjects.     

Effect of age on the orientation of attention: effect of changing the interval between signal and stimulus]

The purpose of the experiment was to examine the effect of aging on spatial attention. One of two possible locations, horizontally arranged, was cued. The subject had to respond to the onset of a visual stimulus, wherever it appeared. The task demand was to orient attention to the stimulated location before producing a response, or to reorient it if the position is not the cued one. Younger and older adults showed the same response pattern, despite the overall slowing down of response presented by the latter.     

Effect of auricular electroacupuncture on the motor manifestations of nociceptive reactions

The effect of low frequency auricular electroacupuncture (EAP) on electromyographic responses (EMGR) of the anterior belly of the digastruc muscle, elicited by stimulation of tooth pulp was studied in cat experiments. It was shown that observed augmentation of the EMGR amplitude produced by EAP depended on tonic activation of gamma-motoneurons of the muscle. This activation directly correlated with EAP intensity. At the same time the latent period of EMGR increased by one-two synapses on account of inhibiting shorter pathways in the afferent part of the reflex arch with intensive EAP. The inhibition of EAP-induced augmentation of EMGR can be achieved by administration of small doses of barbiturates that potentiate the analgetic action of EAP.     

Test of revised method of age estimation from the auricular surface of the ilium

The objective of this paper is to test a revised method of age estimation based on the morphology of the auricular surface recently proposed by Buckberry and Chamberlain ([2002] Am. J. Phys. Anthropol. 119:231-239). The study sample consists of 309 individuals of known sex, age, and race from the Terry and Huntington Collections. Auricular surfaces were scored using the revised technique to determine whether it is equally applicable to both sexes as well as blacks and whites. The auricular surfaces of the same individuals were also scored using the original method of auricular surface scoring developed by Lovejoy et al. ([1985] Am. J. Phys. Anthropol. 68:15-28) to determine whether the revised technique is comparable to the original method in terms of accuracy. Results show that the revised method is equally applicable to males and females as well as blacks and whites. The revised method is less accurate than the original method for individuals between 20-49 years of age, but more accurate for individuals between 50-69 years of age.     

Fluoride-mediated activation of guinea pig neutrophils

In guinea pig periotoneal neutrophils NaF at a concentration of above 5 mM elicited a dose-dependent, delayed and sustained activation of NADPH oxidase. Unlike in human neutrophils, in guinea pig cells, this response was independent of extracellular calcium. Fura2 fluorescence measurements indicated also a fluoride-mediated moderate elevation in the level of cytosolic calcium concentration. Pretreatment of neutrophils with pertussis toxin, blocked fluoride-promoted activation of NADPH oxidase, indicating that NaF stimulation was mediated by a G protein which is a pertussis toxin substrate. NaF-elicited calcium elevation was insensitive to the toxin. Upon transfer of NaF-stimulated cells to a fluoride-free medium, superoxide release declined and calcium levels diminished. The response of the deactivated, fluoride-prestimulated guinea pig neutrophils to a secondary stimulation with phorbol myristate acetate (PMA) or fMet-Leu-Phe, was either unaffected by the previous challenge with NaF (PMA) or augmented by it (the chemotactic peptide). In parallel to the activation of NADPH oxidase, NaF also induced translocation of protein kinase C to cell membranes. This effect was also abolished by a pretreatment with pertussis toxin.     

Fluoride-mediated activation of guinea pig neutrophils

In guinea pig peritoneal neutrophils NaF at a concentration of above 5 mM elicited a dose-dependent, delayed and sustained activation of NADPH oxidase. Unlike in human neutrophils, in guinea pig cells, this response was independent of extracellular calcium. Fura2 fluorescence measurements indicated also a fluoride-mediated moderate elevation in the level of cytosolic calcium concentration. Pretreatment of neutrophils with pertussis toxin, blocked fluoride-promoted activation of NADPH oxidase, indicating that NaF stimulation was mediated by a G protein which is a pertussis toxin substrate. NaF-elicited calcium elevation was insensitive to the toxin. Upon transfer of NaF-stimulated cells to a fluoride-free medium, superoxide release declined and calcium levels diminished. The response of the deactivated, fluoride-prestimulated guinea pig neutrophils to a secondary stimulation with phorbol myristate acetate (PMA) or fMet-Leu-Phe, was either unaffected by the previous challenge with NaF (PMA) or augmented by it (the chemotactic peptide). In parallel to the activation of NADPH oxidase, NaF also induced translocation of protein kinase C to cell membranes. This effect was also abolished by a pretreatment with pertussis toxin.     

Tick-Theileria interactions in response to immune activation of the vector

Watt, D. M., Walker, A. R., Lamza, K. A., and Ambrose, N. C. 2001. Tick-Theileria interactions in response to immune activation of the vector. Experimental Parasitology 97, 89-94. Immune mechanisms towards the haemoprotozoan parasite Theileria parva were investigated in their tick vector, Rhipicephalus appendiculatus. The exoskeletons of adult ticks were initially pierced with bacteria-coated, saline-coated, or sterile dry glass needles. Haemolymph was extracted from the ticks at 6, 24, 48, and 72 h postinjection and applied to bacterial plates to measure the growth inhibition effects. The inhibition zones were larger with all the injected groups compared to uninjected controls. The largest inhibition zones were seen 24 h after injection with bacteria-coated needles. An experiment was carried out to investigate whether antibacterial immune responses were relevant to the parasite/tick relationship and, if so, which parasite form was most vulnerable. R. appendiculatus nymphs were infected with T. parva by feeding on an infected calf and were then injected with needles on days 7, 13, 15, and 17 throughout their moult in an attempt to induce tick immune responses at the same time as different lifecycle forms of T. parva would be present. Salivary glands from the moulted adult ticks in the control and different treatment groups were dissected out and examined for the presence of T. parva sporoblasts. No difference in infection levels was seen in any of the treatment groups compared with the controls, suggesting that immune responses in R. appendiculatus, induced by bacterial injection, do not affect T. parva infections. The fecundity of injected ticks was compared with that of uninjected controls to ensure that the injection procedure itself was not detrimental to the ticks. Injected females had higher engorgement masses than controls but reduced levels of egg hatching.     

Effect of electric stimulation of auricular acupuncture points on H-reflex

The non-nociceptive H-reflex in the musculus soleus were recorded before and after auricular electroacupuncture (AEAP) in patients with vertebrogenic pain syndrome. Changes of the H-reflex on the side of the pain syndrome were observed after ipsi- and contralateral AEAP, the latter producing effect more often. Changes of H-reflex are mainly of facilitating character (71.4%) and, rarely, of inhibitory character (14.3%). In the part of patients AEAP produced distinct facilitation of M-response.     

Effect of epidermal rotation on orientation of scales in the chick

Morphogenesis of scales in the chick was investigated to clarify further the respective roles of the dermis and epidermis. Squares of whole scale-forming skin from the superior surface of the tarsometatarsus were separated with trypsin into dermal and epidermal components, recombined following rotation of the epidermis through varying degrees, grown on a host chorioallantois, and scored for basic shape and orientation of scales as well as for the direction of overlap.     

Effect of synthetic TRH on prolactin release in the pig

Artificial hyperprolactinemia was produced by intravenous administration of synthetic TRH to ovariectomized sows. The prolactin response varied markedly between individual animals. In the range of 25 to 400 mug TRH, the prolactin response was not related to the intravenous dose of TRH. Repetitive administration of 50 mug TRH over a 24-hour period resulted in a prolactin secretory pattern which decreased over time. Prolactin responses to intramuscular doses of TRH were less than those observed after intravenous administration.