Separate and combined effects of a benzodiazepine (alprazolam) and noise on auditory brainstem responses in man.

Auditory brainstem responses (ABRs) were recorded in 60 male or female, anxious or anxiety-free university students, before and after separated or simultaneous intake of alprazolam and exposure to noise. A significant increase of the latencies of the ABRs was found when subjects took alprazolam. This effect is consistent with the presence of gamma-aminobutyric acid (GABA), one of the neurotransmitters at terminals of cochlear efferent fibres A significant increase of the latencies was observed after noise alone. In subjects taking alprazolam when they are exposed to noise, the effect of noise on the ABR latencies is reduced, but not abolished. The effects of alprazolam on the ABR are consistent with the presence of GABA in the medulla and pons. Significant effects of noise upon III-V and I-V intervals suggest that auditory 'fatigue' may involve a retrocochlear component. Differences due to sex appear to be abolished by anxiety.

Chemiluminescent detection of sequential DNA hybridizations to high-density, filter-arrayed cDNA libraries: a subtraction method for novel gene discovery.

A chemiluminescent approach for sequential DNA hybridizations to high-density filter arrays of cDNAs, using a biotin-based random priming method followed by a streptavidin/alkaline phosphatase/CDP-Star detection protocol, is presented. The method has been applied to the Brugia malayi genome project, wherein cDNA libraries, cosmid and bacterial artificial chromosome (BAC) libraries have been gridded at high density onto nylon filters for subsequent analysis by hybridization. Individual probes and pools of rRNA probes, ribosomal protein probes and expressed sequence tag probes show correct specificity and high signal-to-noise ratios even after ten rounds of hybridization, detection, stripping of the probes from the membranes and rehybridization with additional probe sets. This approach provides a subtraction method that leads to a reduction in redundant DNA sequencing, thus increasing the rate of novel gene discovery. The method is also applicable for detecting target sequences, which are present in one or only a few copies per cell; it has proven useful for physical mapping of BAC and cosmid high-density filter arrays, wherein multiple probes have been hybridized at one time (multiplexed) and subsequently "deplexed" into individual components for specific probe localizations.

[Level of anxiety and effects of moderate noise on early auditory evoked potentials]. / Niveau d'anxiété et effets de bruits modérés sur les potentiels évoqués auditifs précoces.

Thirty men and 30 women, 20-25 years old, and selected for presence or absence of anxiety were exposed successively for 15 min to four different noises at the same continuous equivalent level LAeq = 75 dB. Auditory brainstem evoked potentials were recorded before and after exposure to each noise. No difference was found between these noises as to their effects upon evoked potentials. After exposure to noise a significant lengthening of L1, L3 and L5 latencies was observed in men; in women a significant lengthening of L3 and L5 latencies was also present. At the same time, I-V and III-V intervals were significantly increased, without any sex-linked difference, and without any change in I-III interval. L3 and L5 latencies are significantly longer in men than in women; lengthening by noise of L1 and L3 latencies was found significantly longer in men than in women; lengthening by noise of I-V interval was found significantly more important in anxious subjects, without any sex-linked difference. L3 lengthening was also found significantly longer in anxious men than in anxiety-free ones.

[Effects of moderate noises on early auditory evoked potentials in man, in relation to age]. / Effets de bruits modérés sur les potentiels évoqués auditifs précoces, chez l'homme, en fonction de l'âge.

Thirty men and thirty women, the first half of them 40-50 years old, and the other half 15-20 years old, were exposed successively for 15 min to four different noises at the same continuous equivalent level LAeq = 75 dB. Auditory brainstem evoked potentials were recorded before and after exposure to each noise. No difference was found between these noises as to their effects upon evoked potentials. After exposure to noise, a significant lengthening of L1, L3 and L5 latencies was observed in men. No significant lengthening was observed in women, although a lengthening of latencies was present in a majority of them. The three latencies, L3 and L5 latencies in particular, were found significantly longer in men than in women. L1 and L5 latencies were significantly more lengthened by noise in men than in women. In both sexes, L5 latencies were found significantly longer in older subjects; the same was true of L3 latencies in male subjects. Noise did not significantly modify intervals between peaks. I-V interval was found significantly longer in older male and female subjects; the same was true of I-III intervals in men.

Enterolithiasis in two zebras.

Enterolithiasis, as a cause of colic, was diagnosed and treated during surgical intervention in 2 Grant's zebras (Equus burchelli bohmi). The zebras were part of a wild herd in a zoo in the western United States. The clinical signs of enterolithiasis in both zebras were similar to those reported for horses. Analysis of the enterolith from 1 zebra revealed a composition identical to enteroliths that have been analyzed from horses. Three other zebras from this herd had enteroliths at necropsy. Enterolithiasis should be considered as a differential diagnosis for zebras with low-grade obstructive colic.

Cardiovascular effects of impulse noise, road traffic noise, and intermittent pink noise at LAeq = 75 dB, as a function of sex, age, and level of anxiety: a comparative study. I. Heart rate data.

This study aimed at comparing for their cardiovascular effects: a pile-driver noise (P), a gunfire noise (G), a road traffic noise (T), an intermittent pink noise (R). All noises were presented at the same LAeq = 75 dB for 15 min each. Some 120 subjects were divided into 8 subgroups of 15 subjects each: OM (men between 40 and 50 years of age), OF (women, same age range), YM (men, between 15 and 20 years of age), YF (women, same age range), AM (typically anxious men, 20-25 years of age), AF (typically anxious women, same age range), NM (typically anxiety-free men, same age range), and NF (typically anxiety-free women, same age range). Heart rate (HR), digital pulse level, and arterial blood pressure were surveyed before, during, and after exposure to each of the four noises. As regards HR, in subjects at rest, within 5 min preceding exposure to any of the four noises, no differences in prestimulus HR was observed for conditions, age, sex, or anxiety. When the noise was on, the overall HR response was one of increase in all subjects except in OF with G and R noises. In all cases, men provided significantly more important HR responses to noise than women did, indicated by increase in HR, whatever the age. Significantly different HR responses to the different noises were produced by YM and OM. As to the importance of the HR responses induced by them (from the most important to the lesser), noises rank as follows: T, P, G, and R.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular effects of impulse noise, road traffic noise, and intermittent pink noise at LAeq = 75 dB, as a function of sex, age, and level of anxiety: a comparative study. II. Digital pulse level and blood pressure data.

In a previous paper, in which the experimental conditions of the present research are fully described (Parrot et al., this issue), heart rate (HR) was studied in 60 male and in 60 female subjects in response to a pile-driver noise (P), a gunfire noise (G), a road traffic noise (T), and an intermittent pink noise (R), all noises being emitted at the same LAeq = 75 dB for 15 min. Digital pulse level (PL) responses were concomitantly surveyed by the use of pulse oximetry, allowing continuous arterial oxygen saturation (SaO2) readings. An index of pulse reactivity (PRI) could be calculated. Arterial blood pressure was measured 7 times from the beginning to the end of each trial. At rest, within the last minutes preceding each exposure to any of the 4 noises, no difference for conditions or for age in prestimulus PL was observed. In all cases, sex is a highly significant source of variation: Mean resting SaO2 values are higher in women than in men. Mean SaO2 at rest was also found to be significantly higher in anxious (Am) than in anxiety-free (Nm) men. When the noise was on for 15 min, increase in PL prevailed to be in most cases in men. In contrast, decrease or near-zero changes prevailed in 1 case out of 2 in the female subgroups. In all groups, the mean PRIs are significantly higher in men. In no case did the age factor prove to be a significant source of PRI variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular responses to intermittent noise in type A and B female subjects.

Heart-rate and blood pressure measurements allowed analysis of cardiovascular responses (CVRs) to an intermittent pink noise in 9 Type A (coronary prone) and 8 Type B (non-prone) female subjects (Ss). If all Ss are sorted out in sensible, moderately sensible and poorly sensible subgroups, according to similarity in evolution of their heart rates and by completely identifying their heart rate reactivity, results of the analysis do not cross-check those of the behavioral A/B distinction. Although 7 out of 8 B Ss cluster in the moderately sensible subgroup, and although sensible Ss are all of Type A, A Ss are distributed almost equally in the 3 categories, and provide all varieties of CVR responses. Diversity of A Ss for CVR has no relationship with their scores on the Bortner scale.

Individual differences in cardiovascular responses to intermittent noise in human females.

In a group of 13 female subjects submitted in three sessions to regularly alternating pink noise-steps, different techniques were proposed to cope with individual differences in cardiovascular responses. Application of a clustering algorithm to intercorrelation data of individual heart rates (HR) resulted in three subsets of 'sensitive' (S), 'moderately sensitive' (MS) and 'poorly sensitive' (PS) subjects. Only one pattern of HR changes under intermittent noise was observed, but clear-cut differences appeared between sensitivity subgroups which differed for amplitudes of HR responses to noise-steps and for adaptivity to repeated exposures. S subjects always reacted strongly (in fact, progressively strongly); PS subjects always reacted poorly; MS subjects reacted moderately but some of them with exposures either seemed to adapt to the noise or tolerated the noise less and less easily. Although exposure to intermittent noise for 35 min did not prevent a slowing trend of HR in all subjects, no sign of habituation of HR responses to noise-steps was present in any subgroup with repeated exposures. Mean levels of measured systolic and diastolic blood pressure decreased significantly with repeated exposures in MS and PS subjects, but not in S subjects.

[Limb vasodilation provoked by stimulation of the carotid sinus. Importance of histaminergy in the dog]. / Sur la vasodilatation des membres provoquée par la stimulation du sinus carotidien. Importance de l'histaminergie chez le chien.

The vasodilator reflex induced by baroreceptor stimulation was studied on the hindlimbs of the dog. The reflex was induced by norepinephrine (1 microgram/kg) either by intravenous injection or by direct injection into the carotid sinus. In other experiences, the baroreceptor stimulation was obtained by distension of the sinus by rapid injection of 100 ml of physiological serum. The vascular response was studied by recording the hindlimbs blood flow. One of the limbs was previously pretreated by mepyramine and cimetidine (blockage of histaminergic H1 and H2 receptors). During the first minute after the baroreceptor stimulation, blood samples were collected from the venous blood of hindlimbs for histamine assay (fluorometric assay). Our results show: a much lower vasodilation on the limb pretreated by histamine antagonist, a significant increase during the reflex vasodilation of histamine blood levels measured in the efferent blood of hindlimbs. These results, obtained in experimental conditions as physiological as possible (blood perfusion of the limbs with "natural" hemodynamic parameters) permit to conclude that the vasodilation induced by baroreceptor reflex is at least partially histaminergic in the dog.

[Effects of oral contraceptives and of the ovarian cycle on auditory performance at 4 and 6 kHz. Demonstration by functional audiometry]. / Effets des contraceptifs oraux et du cycle ovarien sur la performance auditive à 4 et à 6 kHz. Mise en évidence par audiométrie fonctionnelle.

Absolute thresholds at 4 and 6 kHz were tested in 3 sessions before and after 20 min exposure to 105 dB (A) pink noise in 12 young normal cycling females 11 young females under oral contraceptives and 8 young men. Women under oral contraceptives show lower resting thresholds, more important TTS2 and higher recovery rate than normal cycling women and men. In normal cycling females, non parametric analysis of the data provides evidence that absolute thresholds at 4 and 6 kHz tend significantly to be higher at menses and lower during the postovulatory phase of the cycle.

Effects of the ovarian and contraceptive cycles on absolute thresholds, auditory fatigue and recovery from temporary threshold shifts at 4 and 6 kHz.

Absolute thresholds at 4 and 6 kHz were tested in three sessions before and after 20 min of exposure to 105 dB(A) pink noise in 12 young normal-cycling females, 11 young females on oral contraceptives and 8 young men. Women on contraceptives showed lower resting thresholds, larger temporary threshold shift (TTS) and higher recovery rates than normal-cycling females. The analysis of resting thresholds, auditory fatigue and recovery from auditory fatigue did not evidence any sex-linked difference. Significant differences linked to the phases of the menstrual cycle and of the contraceptive cycle were observed during recovery from auditory fatigue at 4 kHz and in resting thresholds at 6 kHz. Application of Kendall's coefficient of concordance confirmed these results. Absolute thresholds were highest at menstruation and lowest in the postovulatory phase in normal-cycling females and in women on oral contraceptives, during the days of pill ingestion. Oral contraception is probably a more important factor of change in hearing performance than the phases of the menstrual cycle.

[Functional audiometry in women during the preovulatory and menstrual phases]. / Audiométrie fonctionnelle chez la femme en phase préovulatoire et en phase menstruelle.

Hearing performance at 4000 and 6000 Hz was observed in height young female subjects before and after they were submitted to an acoustical stress (105 dBA continuous pink-noise for twenty min) during the pre-ovulatory phase and the menstrual phase respectively. Complementary observations were made in height young female subjects under oral contraceptives in the same conditions and at correspondent phases. In each group, parametric analysis of results does not allow to reject the null hypothesis according which the two phases would not differ for auditory performance, when observed for resting thresholds, temporary threshold shifts and recovery processes of auditory fatigue.

[Binaural disparity for tone thresholds at 4 and 6 kHz: demonstration by iterative audiometry and application of an acoustical stress]. / Disparité interauriculaire de seuils tonaux à 4 et à 6 kHz: mise en évidence par audiométrie itérative et application d'une contrainte acoustique.

In 24 subjects hearing levels at 4 and 6 kHz were measured 28 times. The ear providing the largest number of best scores manifests itself mainly during recovery of auditory fatigue. The degree with which it manifests itself differs strongly from one frequency to the other. In at least 40% of the cases it is not the same ear. In a majority of cases, it is the right one for both frequencies. On the basis of binomial testing, predominance of either ear at 4 kHz is identified in 12 subjects and at 6 kHz in 6 subjects, predominance at both frequencies being present in 3 of them.

[Interauricular disparity of tone thresholds at 4 and 6kHz: functional differences between the best and the worst ear]. / Disparité interauriculaire des seuils tonaux à 4 et à 6kHz: differences fonctionnelles entre oreille la meilleure et oreille la moins bonne]

The predominant ear has been identified on the basis of binomial tests in 12 subjects at 4 kHz and in 6 subjects at 6 kHz. On an average its hearing thresholds are significantly lower than those of the other ear. At 4kHz its response to an acoustical stress appears to be proportionally more important than that of the other ear, but is equivalent at 6 kHz. For both frequencies recovery in the best ear proceeds significantly quicker than in the other ear.

[Short-term cardiovascular responses to repeated exposure to intermittent noise. Interindividual differences]. / Réponses cardio-vasculaires à court terme à l'application répétée d'un bruit intermittent. Différences inter-individuelles.

Human subjects were exposed for two (or three) sessions to the same runs of 103 dB (A) pink noise-steps alternating with 40 dB (A) low level pink noise. From one session to the following their cardiovascular responses seem to achieve an adjustment. Differences between them depend on two features: (1) some of them achieve a negative feedback reaction from the second exposure, when in others such a reaction is delayed until the third exposure; (2) parallelism or opposition between evolutions of heart rate and arterial blood pressure respectively.

[Cardiovascular responses to repeated exposures to intermittent noise. Tentative validation of the law of initial value]. / Réponses cardio-vasculaires à l'application répétée de bruits intermittenis. Essai de validation de la loi de la valeur initiale.

Eighteen female undergraduate subjects were submitted three times to an intermittent 55 min. pink-noise made of 6 x 5 min. periods at 103 dB (A), alternating with 5 x 5 min periods at 40 dB (A). Arterial blood-pressure was measured by the auscultatory method during the last minute before each noise-step (initial value) and during the first minute following it. Concomitant values of heart-rate (continuously recorded) were also taken into account in the same way. Arterial blood pressure as well as heart-rate homeostatic response to both types of noise-steps obey the Law of initial value, respectively in 38 p. 100 and 33 p. 100 of the cases, but the Law fails to reveal adaptive changes in responses from the first to the third exposure to acoustical stress.