Chronic study on the neuronal excitability of the cochlear nuclei of the cat following electrical stimulation

OBJECTIVES: To determine: (i) the prevalence, reasons for, and demographic and psychosocial predictors of prostate cancer screening among a randomly selected sample of men; and (ii) to estimate the community expenditure involved in the screening of asymptomatic men. SUBJECTS AND METHODS: A random sample of men aged 40-79 years was selected from the State Electoral Register of New South Wales, Australia, and asked to complete a computer-assisted telephone interview. The questions determined their demographic characteristics, their subjective health rating compared with others of the same age (5-point scale), the prevalence and reasons for any screening for prostate cancer ('ever screened' and 'screened within the last 12 months'), whether they had undergone a digital rectal examination (DRE), a blood test for prostate-specific antigen (PSA) or transrectal ultrasonography (TRUS), and the prevalence of urinary symptoms. Those who had been screened were then asked to nominate the single most important factor in the decision to undergo prostate cancer screening. To estimate community expenditure, the costs for prostate cancer screening were estimated by applying Medicare schedule charges to the screening and subsequent diagnostic tests performed. Two scenarios were developed to estimate costs: the first used guidelines which do not recommend the use of routine screening for all asymptomatic men, and the second was based on guidelines where the routine use of PSA or TRUS as part of a periodic health examination is not recommended, but the use of DRE in asymptomatic men aged 50-70 years is. RESULTS: Of the 551 eligible participants, 86% completed the interview; 44% of participants reported that they had 'ever' been screened, whilst 23% had been screened in the year before the study. Among those who had been screened, the reason reported most often for screening, apart from symptoms and family history, was the doctor's recommendation after a medical assessment of their prostate cancer risk status. Screening status was predicted both by the age of the man and his symptom score. As a result, the community expenditure in New South Wales for screening among asymptomatic men was estimated to be A$6.4 million and A$5.2 million for the first and second scenarios, respectively. CONCLUSIONS: The results of this study suggest that, despite the recommendations of primary bodies that asymptomatic men not be screened for prostate cancer, screening is occurring at a high level and with significant costs to the healthcare system.     

Glycine receptors in adult guinea pig brain stem auditory nuclei: regulation after unilateral cochlear ablation

Behavioral, endocrinological, and pharmacological data suggest that the emotional response of rodents to the elevated plus-maze alters as a function of prior test experience. In the present study, 74 intact male Swiss-Webster mice were exposed to the plus-maze for 5 min on each of 3 consecutive days, with all test sessions recorded on videotape. Behavior patterns for each trial were scored using ethological analysis software and the resultant database subjected to a number of statistical treatments. Analysis of full session profiles (i.e., 5 min total scores) showed that a single prior undrugged experience of the maze increases behavioral indices of anxiety and that these alterations are either maintained or further enhanced on subsequent trials. Furthermore, the behavioral profile evident by trial 3 was largely unchanged when animals were reexposed to the maze 10 days later. More detailed (i.e., min by min) examination of behavior patterns within and between trials demonstrated that unambiguous open arm avoidance is acquired by the third minute of trial 1, and that the behavioral profile evident by the end of trial 1 is (a) markedly different to that seen at the beginning of that trial, and (b) generally maintained or even accentuated on trials 2 and 3. The implied impact of prior test experience on future behavioral strategy in the maze was strongly supported by a series of factor analyses. Thus, while the factor associations of vertical activity and directed exploration remained constant across trials, trial 2 and 3 anxiety measures loaded on a separate factor to that loading trial 1 anxiety measures. A similar trial 1 vs. trials 2 and 3 dissociation was observed for measures of locomotor activity. Although the present findings are consistent with the proposal that prior test experience produces a qualitative shift in emotional response to the elevated plus-maze, the precise basis for this change as well as its full significance for our understanding of anxiety-related processes remain to be determined.     

Envenomation by exotic snakes

Snake bite envenoming in tropical areas affects an estimated one million people according to the World Health Organization. Two studies showed that annual mortality is between 30,000 and 50,000 people. Clinically cobra and viper envenoming are the most well known but several other snakes cause characteristic manifestations allowing species-specific diagnosis. Immuno-enzymatic tests are a useful diagnostic tool that is currently expanding but remains available only in developing countries because of cost. Treatment consists mainly of serotherapy in the most severe cases. Use of purified products and fragments active specifically on toxins and enzymes is both safer and more effective. Heparinotherapy should be used only when indicated by clinical manifestations and hemostasis testing. Management of envenoming must be organized in function of antivenom availabilities in a given region. Future improvements in immuno-enzymatic tests and antivenoms should allow more successful treatment of severe snake bite envenoming.     

The detection of fear-relevant stimuli: Are guns noticed as quickly as snakes?

Potentially dangerous stimuli are important contenders for the capture of visual-spatial attention, and it has been suggested that an evolved fear module is preferentially activated by stimuli that are fear relevant in a phylogenetic sense (e.g., snakes, spiders, angry faces). In this study, a visual search task was used to test this hypothesis by directly contrasting phylogenetically (snakes) and ontogenetically (guns) fear-relevant stimuli. Results showed that the modern threat was detected as efficiently as the more ancient threat. Thus, both guns and snakes attracted attention more effectively than neutral stimuli (flowers, mushrooms, and toasters). These results support a threat superiority effect but not one that is preferentially accessed by threat-related stimuli of phylogenetic origin. The results are consistent with the view that faster detection of threat in visual search tasks may be more accurately characterized as relevance superiority effects rather than as threat superiority effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biocompatibility of cochlear implants

Ceramic, titanium and platinum guarantee a perfect bio-compatibility for cochlear implants. Moreover the long term efficacy of the electrode nerve interface is obtained thanks to a limited electric current density. Failure risks of implanted electronic are decreased by use of carefully selected components.     

Epidemiological study on leptospirosis in Brazilian snakes

A case is reported by the authors of a progressive benzene hemopathy with a final leukemic evolution. The leukemic pattern was an autopsy "surprise', inasmuch as never, even in the hours just before death, could leukemic cells be detected in the blood stream. The authors discuss some pathogenic aspects, with particular emphasis on the systemic spreading of a malignant hemopathy from very few leukemic cells in bone marrow.     

Laboratory observations of trailing behavior in garter snakes.

Using a Y-maze apparatus, trained 9 garter snakes (THamnophilis sirtalis sirtalis) to follow an earthworm-extract trail. Correct trailing improved significantly as training progressed. All Ss were able to attain a trailing criterion of 8 out of 10 correct trials by the termination of training. For each trial, the number of tongue flicks each S made was recorded and tongue flick rate calculated. Tongue flick rate was found to be highly characteristic and constant for individual Ss. In addition, running speed and tongue flick rate were found to be significantly correlated. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What have snakes taught us about integrins?

Snake venoms contain unique components that affect cell-matrix interactions. Disintegrins represent a class of low molecular weight, Arg-Gly-Asp (RGD)-containing, cysteine-rich peptides purified from the venom of various snakes among the Viperidae and Crotalidae. They bind with various degrees of specificity to integrins alpha IIb beta 3, alpha 5 beta 1 and alpha V beta 3 expressed on cells. Snake venom metalloproteases (high molecular mass haemorrhagins) also contain disintegrin-like domains, in addition to zinc-chelating sequences. Membrane-anchored ADAMs (A Disintegrin And Metalloprotease domain), multidomain molecules consisting of metalloprotease, disintegrin-like, cysteine-rich, and epidermal growth factor domains, a transmembrane domain and a cytoplasmic tail, are a new family of proteins. In the light of the large number and wide distribution of ADAMs, they may participate in cell-cell fusion events, including sperm-egg binding and fusion, myoblast fusion and other cell-cell and cell-matrix interactions. The structure-function relationship of these molecules is discussed.     

The stretching nonlinearity of the basilar membrane in a cochlear model

Recently it has been suggested that the stretching nonlinearity of the basilar membrane might be responsible for the observed nonlinear behaviour of basilar membrane motion. In the present study this type of nonlinearity is investigated, both by estimating its influence in an analytical manner, and by calculating its effect numerically, using a regular pertubation method. The conclusion reads that the stretching nonlinearity does not explain the observed nonlinear phenomena; not only is stretching negligible at normal sound levels, but it also fails to fit the data qualitatively, because of its typical hard-spring effect. In consequence, the origin of cochlear nonlinearity is not to be sought in the macromechanics of the inner ear, but in the more detailed processes in th organ of Corti-tectorial membrane complex.     

稳定核激发态的奇特结构

在相对论平均场理论框架下,利用壳模型方法处理对关联,研究17N和18O基态和激发态性质,计算17N和18O基态和激发态的中子和质子方均根半径,给出中子和质子的密度分布.结果表明:这些核的激发态半径比基态大,中子密度具有更大的空间分布,形成了类晕或皮的奇特结构.     

The effect of mannitol upon cochlear dysfunction induced by transient local anoxia

Transient local anoxia of the cochlea was induced by pressing the labyrinthine artery, and compound action potential (CAP) or endocochlear potential (EP) was measured before and after transient local anoxia ranging from 5 to 60 min using 106 albino guinea pigs. The complete interruption of the cochlear blood flow by this procedure and its full restoration after releasing the pressure on the artery was confirmed by a laser-Doppler flowmeter. The anoxia of less than 10 min induced no post-anoxic cochlear dysfunction, whereas the anoxia of a longer duration induced an irreversible dysfunction of the cochlea. It was evident that the post-anoxic recovery of the CAP threshold was worse as the anoxia period was prolonged, and CAP was almost completely abolished after 60-min anoxia. In animals which were administered mannitol intravenously just after the restoration of the cochlear blood circulation, the recovery of the CAP threshold was significantly better than that in the control animals, when the animals were subjected to local anoxia of 15- to 30-min duration. No beneficial effect, however, was observed in the 60-min anoxia group. In conclusion, local anoxia of 10 min or longer caused cochlear dysfunction, which was partially but significantly alleviated by mannitol.     

The level dependence of response phase: observations from cochlear hair cells

Hair cell responses are recorded from third turn of the guinea pig cochlea in order to define the relationship between hair cell depolarization and position of the basilar membrane. Because the latter is determined locally, using the cochlear microphonic recorded in the organ of Corti (OC) fluid space, no corrections are required to compensate traveling wave and/or synaptic delays. At low levels, inner hair cells (IHC) depolarize near basilar membrane velocity to scala vestibuli reflecting the free standing nature of their stereocilia. At high levels, the time of depolarization changes rapidly from velocity to scala vestibuli to the scala tympani phase of the basilar membrane response. This change in response phase, recorded in the fundamental component of the IHC response, is associated with a decrease in response magnitude. The absence of this behavior in OC and outer hair cell responses implies that basilar membrane mechanics may not be responsible for these response patterns. Because these features are reminiscent of the magnitude notches and the large phase shifts observed in single unit responses at high stimulus levels, they provide the IHC correlates of these phenomena.