Different requirements for membrane fusion mediated by the envelopes of human immunodeficiency virus types 1 and 2

CD4+ cells derived from the human cell lines U87MG and SCL1 cannot be infected by human immunodeficiency virus type 1 (HIV-1) or fuse with cells expressing the HIV-1 envelope. This block was complemented in heterokaryons with HeLa cells and probably reflects the absence of cellular factors necessary for membrane fusion. Since U87MG cells expressing CD4 are permissive to HIV-2, distinct cellular factors could be required for fusion mediated by two related human retroviruses.     

Effects of reward timing information on cue associability are mediated by amygdala central nucleus.

The central nucleus of the amygdala (CeA) has been implicated in a range of associative learning phenomena often attributed to changes in attentional processing of events. Experiments using a number of behavioral tasks have shown that rats with lesions of CeA fail to show the enhancements of stimulus associability that are normally induced by the surprising omission of expected events. By contrast, in other tasks, rats with lesions of CeA show normal enhancements of associability when events are presented unexpectedly. In this experiment, we examined the effects of CeA lesions on changes in cue associability in a reward timing task. In sham-lesioned rats, the associability of cues that were followed by stimuli that provided reward timing information was maintained at higher levels than that of cues that were followed by uninformative stimuli. Rats with lesions of CeA failed to show this advantage. These results indicate that the role of CeA in the modulation of associability is not limited to cases of event omission. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Lipopolysaccharide induces sickness behaviour in rats by a vagal mediated mechanism

A 52-year-old man was hospitalized for a right adrenal tumor which had been incidentally found by abdominal CT scan for examination of colon cancer. Laboratory and endocrine findings were within the normal limits except for increased urinary concentrations of noradrenaline and dopamine. Adrenal angiography revealed that the feeding artery of the tumor was the inferior suprarenal artery. Adrenal venous blood sampling studies detected no abnormalities in the concentrations of catecholamine, cortisol or aldosterone. Right adrenalectomy was performed and the tumor was histologically diagnosed as ganglioneuroma. Ganglioneuroma is a benign tumor originating from the sympathetic nerve ganglion. The adrenal origin of the tumor is relatively rare and 60 cases of adrenal ganglioneuroma including our case have been reported in Japan.     

Regulation of hly expression in Listeria monocytogenes by carbon sources and pH occurs through separate mechanisms mediated by PrfA

Expression of the PrfA-controlled virulence gene hly (encoding the pore-forming cytolysin listeriolysin) is under negative regulation by readily metabolized carbon sources in Listeria monocytogenes. However, the hyperhemolytic strain NCTC 7973 exhibits deregulated hly expression in the presence of repressing sugars, raising the possibility that a defect in carbon source regulation is responsible for its anomalous behavior. We show here that the activity of a second glucose-repressed enzyme, alpha-glucosidase, is 10-fold higher in NCTC 7973 than in 10403S. Using hly-gus fusions, we show that the prfA allele from NCTC 7973 causes deregulated hly-gus expression in the presence of sugars in either the wild-type or the NCTC 7973 background, while the 10403S prfA allele restores carbon source regulation. However, the prfA genotype does not affect the regulation of alpha-glucosidase activity by repressing sugars. Of the two mutational differences in PrfA, only a Gly145Ser change is important for regulation of hly-gus. Therefore, NCTC 7973 and 10403S have genetic differences in at least two loci: one in prfA that affects carbon source regulation of virulence genes and another in an unidentified gene(s) that up-regulates alpha-glucosidase activity. We also show that the decrease in pH associated with utilization of sugars negatively regulates hly-gus expression, although sugars can affect hly-gus expression by another mechanism that is independent of pH.     

Patterned (single) alternation in infant rats after combined or separate lesions of hippocampus and amygdala.

The role of the developing hippocampus and the amygdala on patterned (single) alternation (PA) in the infant rat was investigated in 4 experiments. In Exps 1 and 2, Ss were given 2 bilateral electrolytic hippocampal lesions or sham surgeries at 10 or 11 days of age and were trained 6 days later in a straight runway. In Exp 1, there were 120 trials in 1 day, with an 8-, a 15-, or a 30-s intertrial interval (ITI). PA learning occurred in lesion and sham Ss at the 8- and 15-s ITIs. In Exp 2, training was extended to 240 trials over 2 days, with a 30- or 60-s ITI. Sham and lesion Ss showed PA at the 30-s ITI, but the emergence of PA was delayed in the lesion pups at the 60-s ITI. In Exp 3, amygdaloid lesions had no effect on PA learning at the 8-s ITI. However, when Ss with hippocampal and amygdaloid lesions were trained at the 8-s ITI, the emergence of PA was delayed, and its size was reduced (Exp 4). Results argue for a role of the hippocampus in PA learning at long ITIs and suggest that, even in 16-day-old Ss exposed to an 8-s ITI, the combined hippocampal and amygdaloid lesion produces a deficit greater than either the hippocampal or the amygdaloid lesion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lysosomal targeting of P-selectin is mediated by a novel sequence within its cytoplasmic tail

Signals controlling the intracellular targeting of many membrane proteins are present as short sequences within their cytoplasmic domains. P-selectin is a type I membrane protein receptor for leukocytes, acting during the inflammation response. Heterologous expression experiments have demonstrated that its 35-residue cytoplasmic tail contains signals for targeting to synaptic-like microvesicles, dense-cored granules, and lysosomes. We have examined the lysosomal targeting information present within the cytoplasmic tail by site-directed mutagenesis of horseradish peroxidase-P-selectin chimeras followed by transient transfection in H.Ep.2 cells. Assaying lysosomal targeting by subcellular fractionation as well as intracellular proteolysis, we have discovered a novel lysosomal targeting signal, KCPL, located within the C1 domain of the cytoplasmic tail. Alanine substitution of this tetrapeptide reduced lysosomal targeting to the level of a tailless horseradish peroxidase-P-selectin chimera, which was previously found to be deficient in both internalization and delivery to lysosomes. A proline residue within this lysosomal targeting signal makes a major contribution to the efficiency of lysosomal targeting. A diaminobenzidine density shift procedure established that chimeras with an inactivated KCPL sequence are present within transferrin-positive compartments. Such a mutant also displays an increased level of expression at the plasma membrane. Our results indicate that the sequence KCPL within the cytoplasmic tail of P-selectin is a structural element that mediates sorting from endosomes to lysosomes.     

Ultrastructural localization of filamentous actin within neuronal interphase nuclei in situ

Previous biochemical studies utilizing isolated nuclei and nuclear matrices have shown actin to be a constituent of the interphase nucleus. In addition, recent ultrastructural work has shown the presence of actin and myosin within nuclei of interphase cells in situ. It was unclear, however, whether this intranuclear actin is present in the unpolymerized globular actin or the filamentous (F)-actin form. The present work, using confocal microscopy and ultrastructural cytochemical techniques, demonstrates the presence of F-actin within interphase nuclei of intact, uncompromised, dorsal root ganglion neurons in vitro and in vivo. Labeling by FITC-phalloidin detected the presence of intranuclear F-actin adjacent to the nucleolar periphery in a small fraction of cells in vitro, an observation confirmed by three-dimensional reconstruction. Ultrastructural analyses of cells exposed to heavy meromyosin (HMM), showed the presence of typical "arrowhead" complexes. The observation that these complexes were associated with nucleoli confirms that the intranuclear ligand detected by FITC-phalloidin indeed represents F-actin. Postembedding labeling with HMM conjugated to 20-nm colloidal gold (HMM-Au20) resulted in labeling similar to that obtained with HMM. However, HMM-Au20 was found to label a much larger fraction of cells, both in vitro and in vivo, than did FITC-phalloidin or HMM. This finding indicates that labeling with HMM-Au20 more accurately reflects the extent of actin polymerization in nuclei. Results from double labeling with HMM-Au20 and an antibody to alpha-sarcomeric actin confirmed that only a small amount of nuclear actin is in the F-form. Together, these results represent a first ultrastructural demonstration of the presence of F-actin in nuclei of neurons. While the role of nuclear F-actin has yet to be defined, the results suggest that F-actin may represent a component of the molecular motor responsible for the dynamic positioning of specific chromatin domains into the tissue-specific, nonrandom patterns observed in many cell types.     

Ciliated neurons and different types of synapses in anterior hypothalamic nuclei of reptiles

The magnocellular paraventricular and supraoptic nuclei and the parvocellular preoptic and periventricular nuclei have been studied by light and electron microscopy in Emys orbicularis, Lacerta agilis and Elaphe longissima. The ultrastructure of cerebrospinal fluid (CSF)-contacting neurons was described in the preoptic and periventricular nuclei of Emys and Lacerta species. Single 9 X 2 + 0 cilia similar to those of the CSF-contacting dendritic terminals were found on perikarya of non CSF-contacting nerve cells, in all four investigated nuclei. The cilia project from funnel-like invaginations of the perikarya into the intercellular space. In the neurons of the nuclei studied, granular vesicles were found, their size being mainly 1,600 A in the paraventricular nucleus, about 1,800 A in the supraoptic nucleus, 1,100 A in the periventricular nucleus and 800 A, or up to 1,250 A in the preoptic nucleus. In general, the neurons possess synapses of the axo-somatic, axo-somatic spine, axo-dendritic and axo-dendritic spine types. In the supraoptic nucleus, multiple interdigitated synapses were observed. Presynaptically, eif different sizes (600 to 800 A, about 1,100 A, 1250 A, and up to 2,000 A) were found. It is discussed whether the above described 9 X 2 + 0 cilia may represent some kind of hypothalamic sensory structure that earlier physiological studies postulated to exist. The ciliated hypothalamic perikarya are considered by the authors to be a more differentiated form of the CSF-contacting neurons. The different types of synapses indicate multilateral connections of the nerve cells of the nuclei studied.     

Acoustic measures of dysphonic severity across and within voice types

The purpose of the study was to explore an interaction between pathologic voice type and the acoustic prediction of dysphonic severity. One hundred and two phonatory samples, representing a wide range of laryngeal conditions, were categorized by listeners into three voice types: breathy, rough, and hoarse. A second group of trained listeners rated the severity of the samples on a 7-point scale. Twenty-five frequency- and time-domain measures were used to predict perceptual severity. Multiple regression analyses showed that the most useful measure for the prediction of severity across voice types was noise-to-harmonic ratio (NHR). The severity of individual voice types was predicted with differential results on the basis of both short- and long-term measures of perturbation.     

What types of visual recognition tasks are mediated by the neural subsystem that subserves face recognition?

Three divided visual field experiments tested current hypotheses about the types of visual shape representation tasks that recruit the cognitive and neural mechanisms underlying face recognition. Experiment 1 found a right hemisphere advantage for subordinate but not basic-level face recognition. Experiment 2 found a right hemisphere advantage for basic but not superordinate-level animal recognition. Experiment 3 found that inverting animals eliminates the right hemisphere advantage for basic-level animal recognition. This pattern of results suggests that the cognitive and neural mechanisms underlying face recognition are recruited when computational demands of a shape representation task are best served through the use of coordinate (rather than categorical) spatial relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Different types of self-injurious behavior in bulimia nervosa

This study introduces a new method of determining sex based on four morphological features of the posterior, distal humerus. The technique was developed on a 20th century anatomy series, the University of Toronto Grant Skeletal Collection, and was tested on 35 known individuals from the University of New Mexico Documented Collection and 93 individuals from the William M. Bass Donated Skeletal Collection. Four statistically significant characteristics relating to the carrying angle of the arm are identified (p < 0.05). Together, they are capable of determining sex with 92% accuracy.     

Effects of passive-avoidance training on sleep-wake state-specific activity in the basolateral and central nuclei of the amygdala.

This study examined the effects of intense emotional learning on the sleep-wake state-specific electroencephalographic (EEG) activities of the basolateral (BLA) and central (CeA) nuclei of the amygdala. Rats were trained on a passive-avoidance learning (PAL) protocol that was followed by 6 hrs of undisturbed polygraphic recording and a PAL test. After PAL training, the total amount of REM sleep decreased; high-frequency EEG power decreased in the CeA during REM sleep and increased in the BLA during all sleep-wake stages. These results suggest that there is no homeostatic demand for REM sleep after intense emotional learning. However, the PAL-specific changes in the local EEG suggest that some form of memory processing may occur within the amygdala during REM sleep. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pressor effects elicited by stimulation within the medullary raphe nuclei of the guinea pig (Cavia porcellus)

A series of 120 pathologically verified intraspinal tumors was analyzed for the relative incidence and location of the tumors as well as the distribution of age and sex. These data were compared to series from Taiwan, mainland China, Thailand, Korea, Japan, Iran, India, and countries in the West. The ratio of brain to intraspinal tumors was about 5:1 in Taiwan, higher than those reported in China, Korea, and in the West. The male to female ratio is about six to five. For most tumors, male predominance is noted except for meningioma. The incidence of intraspinal tumors in the order of frequency is nerve sheath cell tumor(NSCT), metastatic tumors, meningioma, glioma, congenital tumors, and vascular tumors. In the East, the incidence of NSCT is about 40%, and meningioma is about 10%. In the West, they are both about 20%. Congenital tumors accounted for only 3.3%. In China, it was about 12% and this is the highest incidence of dysembryoplastic tumors in the world. Glioma has similar incidence (about 10%) in Taiwan, China, Thailand, Japan, and Iran (about 10%), whereas it is about 15% in the West and India. Korea has the highest incidence of glioma, (32.3%). Low incidences of metastatic intraspinal tumors (4.6-5.5%) were noted in China and Japan, but a higher incidence (14.2-24.2%) was seen in Taiwan, Iran, and the West. The most common metastatic tumors in the order of frequency is tumors of unknown origin, lung cancer metastasis, hepatoma, and breast cancer. The high percentage of unknown origin of metastasis may have resulted from loss of follow-up and lack of postmortem studies.     

Angiotensin II inhibits long-term potentiation within the lateral nucleus of the amygdala through AT1 receptors

We have treated 16 patients with recurrent complex elbow instability using a hinged external fixator. All patients had instability, dislocation or subluxation of the ulnohumeral joint. The injuries were open in eight patients and were associated with 20 other fractures and five peripheral nerve injuries. Two patients had received initial treatment from us; 14 had previously had a mean of 2.1 unsuccessful surgical procedures (1 to 6). The fixator was applied at a mean of 4.8 weeks (0 to 9) after the injury and remained on the elbow for a mean of 8.5 weeks (6 to 11). After treatment we found the mean range of flexion-extension to be 105 degrees (65 to 140). At a final follow-up of 23 months (14 to 40), the mean Morrey score was 84 (49 to 96): this translated into one poor, three fair, ten good and two excellent results. Complications included one fractured humeral pin, one temporary palsy of the radial nerve, one recurrent instability, one wound infection, one severe pin-track infection and one patient with reflex sympathetic dystrophy. Although technically demanding, the use of the fixator is an important advance in the management of recurrent complex elbow instability after failure of conventional treatment.     

Activation of separate calcium and A-kinase-dependent pathways by ACTH

Although cAMP has long been regarded as the primary intracellular messenger for ACTH-stimulated cortisol secretion, a requirement for Ca2+ is well established. However, a specific mechanism which couples ACTH receptor activation to increased intracellular calcium concentration in the adrenal cortical cell has not been elucidated. Here, we present evidence for a specific model in which ACTH at picomolar concentrations induces cAMP which acts through kinase-dependent and independent pathways to stimulate cortisol secretion. Along one of these pathways, cAMP acts directly to depolarize cells by inhibition of a specific non-inactivating K+ channel (I(AC)). This model provides a specific mechanism whereby cAMP-mediated inhibition of I(AC) is tightly coupled to depolarization-dependent Ca2+ entry and cortisol secretion. Ca2+ and cAMP are dual second messengers in the ACTH signalling pathway that are linked through I(AC) K+ channels.