Normalization of hypertensive responses during ambulatory surgical stress by perioperative music.

OBJECTIVE: The purpose of this study was to determine whether cognitive appraisals of stress level and hypertensive responses to ambulatory ophthalmic surgery can be ameliorated by patient-selected music. METHODS: We studied 40 elderly individuals requiring ophthalmic surgery, 20 in an experimental group (mean age, 74 years) and 20 in a control group (mean age, 77 years). All patients had an established resting blood pressure <140/90 mm Hg. In the experimental group self-selected music was provided by headphones throughout the preoperative, surgical, and postoperative periods. In the control group patients had neither headphones nor music. All patients received similar (weight-determined) doses of alfentanil and midazolam during surgery. Heart rate, blood pressure, and patient-reported stress and coping levels were the dependent variables. RESULTS: In both groups, blood pressure values were normal (approximately 129/82 mm Hg) during screening examinations 1 week before surgery. On the day of surgery both groups displayed increased preoperative blood pressures (approximately 159/92 mm Hg) associated with increases in heart rate (by approximately 17 beats/min). Intraoperative blood pressures in the experimental group returned quickly to screening baseline values, whereas the control group experienced persistent elevations in intraoperative blood pressure similar to preoperative levels. Over the course of the surgical experience, patients with music reported significant reductions in perceived stress and increases in coping abilities (p < .001), whereas those without music did not. CONCLUSIONS: The perceived stress of ambulatory surgery in geriatric patients is associated with a clinical hypertensive response that is ameliorated by self-selected perioperative music, which also decreases perceived stress and increases patients' sense of personal control and well-being.

New measures of sperm motion. I. Adaptive smoothing and harmonic analysis.

Several kinematic measures from computer-aided sperm analysis (CASA) instruments depend critically upon the computation of the spatially averaged path of a sperm's curvilinear swimming trajectory. Presently available instruments compute the average path by smoothing the curvilinear trajectory using a fixed-length running average. We demonstrate that this method significantly distorts the spatially averaged path for irregularly swimming sperm, both within and between trajectories, resulting in inaccurate calculations for the velocity of the average path (VAP), amplitude of lateral head displacement (ALH), beat-cross frequency (BCF), wobble of the curvilinear trajectory (WOB), and straightness of the curvilinear trajectory (STR). The authors introduce an alternative approach, based on engineering signal processing techniques, where the width of the running average is adapted to the changing wavelengths of the major spatial oscillations of each curvilinear trajectory. How this adaptive method results in less distortion of the average path and produces more accurate characterizations of the above measures is shown. This method is implemented in a computer program developed by the authors, called PathTool. It is also demonstrated that the simple methods used to characterize the frequency and amplitude of the major oscillation in a sperm's curvilinear trajectory (ie, BCF and ALH) are only accurate for the most periodic, progressive, and symmetrical trajectories. Three new measures are introduced, based on mathematical harmonic analysis, that are more robust alternatives to the present methods. These new methods and measures are initially evaluated using prototypical sperm trajectories from human semen. Results suggest that adaptive smoothing and harmonic analysis produce more accurate estimates of the frequency and magnitude of oscillations in sperm trajectories than the method based on fixed-length smoothing, BCF, and ALH.

Studies on tumor induced angiogenesis.

Methods were developed to test angiogenic response to human tumor implants and various biologic agents in the cornea of rabbits and non-human primates (Macaca arctoides). Crude PDGF preparations were found to have significant angiogenic effect. Purified, recombinant PDGF preparations were also effective inhibitors (e.g. pentoxifylline (Px) (which also were found to release PgI2 and t-PA) inhibited human tumor implant induced angiogenesis and reduced spontaneous metastases in 3 transplantable murine tumors (Furth-Columbia Wilms' tumor in Furth-Wistar rats, C-1300 neuroblastoma in A/J mice and HM-Kim mammary carcinoma in Wistar rats) but not in the NIH adenocarcinoma in Balb/c mice. Sodium diethyldithiocarbamate (DDTC), a metal complexing agent with special affinity to copper and anti-thyroid as well as, immune stimulating activity was shown to be anti-angiogenic and to potentiate the effect of Px. The anti-fibrinolytic agents epsilon amino caproic acid (EACA) and tranaxamic acid (t-AMCHA) were anti-angiogenic. DDTC and Px were synergistic from this point of view.

Studies on tumor induced angiogenesis.

Methods were developed to test the angiogenic response to human tumor implants and various biologic agents in the cornea of rabbits and non-human primates (Macaca arctoides). Human malignant melanoma tissue and crude platelet derived growth factor (PDGF) preparations had significant angiogenic effects. Purified, recombinant PDGF preparations were also effective initiators. Hemorheologic agents which also inhibit platelet aggregation [e.g. pentoxifylline (Px) (Trental) (also found to release PgI2 and tissue plasminogen activator (t-PA)] inhibited human tumor implant-induced angiogenesis. Sodium diethyldithiocarbamate (DDTC), a metal complexing agent with special affinity to copper and anti-thyroid as well as immune stimulating activity, was shown to be anti-angiogenic and to increase the effect of Px. The anti-fibrinolytic agents epsilon amino caproic acid (EACA) and tranexamic acid (t-AMCHA) were anti-angiogenic.

Observations on the acoustic reflex threshold in institutionalized retarded adults taking mellaril and/or thorazine.

The present study was designed to investigate whether mellaril and thorazine, when used alone and in combination with other medications by mentally retarded clients, either abolish acoustic reflexes or compromise estimates of hearing sensitivity based on acoustic reflex measures. Acoustic reflex thresholds were determined in 35 normal-hearing institutionalized mentally retarded subjects who were regular users of the medications under investigation. Five sensitivity prediction methods based on acoustic reflex thresholds were applied to the data. The results of the study showed that acoustic reflexes were present in most subjects. However, the accuracy of all the acoustic reflex-based sensitivity prediction methods was quite poor with greatly exaggerated predictions of hearing loss. The methods based solely on noise reflex thresholds provided better accuracy than those based on noise-tone differences. In general, the accuracy of the prediction methods decreased as the number of medications used by the subjects increased. It is argued that the results provide evidence for reticular activating system mediation of acoustic reflex activity.

Morphometric analysis of spermatozoa in the assessment of human male fertility.

A videomicrographic system was developed for measurement of morphometric parameters of human spermatozoa. Contours of the images of spermatozoa on a video monitor are digitized by manually tracing them with the cursor of an electromagnetic digitizer integrated to a microcomputer. The accuracy and precision of the methodology were evaluated. A comparison of human sperm heads in shallow wet preparations and in dried, stained preparations indicated that the latter were smaller in length, width, projected area, and circumference, but that the ratio length/width was not different. An analysis was made of 457 ejaculates from 16 fertile donors. The variation between ejaculates within donors was similar in magnitude to the variation between donors. A study was performed comparing seminal sperm morphometry in single specimens from 30 fertile and 30 infertile men. The sperm head length/width ratio was the parameter that differed the most between these two groups. Moreover, it was the per-ejaculate variability of this parameter, rather than the central tendency, that maximized the difference.

Comparison of the revised Hearing Performance Inventory with audiometric measures.

Hearing Performance Inventory scores were correlated with sensitivity, discrimination, and sensitivity + discrimination measures for 39 subjects with noise-induced hearing loss. The highest correlation obtained (0.67) was with monosyllabic speech discrimination in noise. However, there were not significant differences in correlations among the three types of audiometric measures. The audiometric variables accounted for less than half of the variance in Hearing Performance Inventory scores; therefore they are inadequate in predicting the amount of self-perceived hearing difficulties. The need for a variety of hearing handicap scales is discussed.

Modulation of macrophage superoxide release by purine metabolism.

Metabolic flux through the purine salvage pathway appears to modulate superoxide secretion by elicited macrophages. Exogenous adenosine, the first substrate of this pathway, stimulates superoxide secretion, and Allopurinol, a specific inhibitor of xanthine oxidase, inhibits superoxide secretion. The effects of these agents are additive since it was possible for each to neutralize the effects of the other when given in combination. In these experiments, the purine salvage pathway was responsible for over ten times the superoxide production attributable to the NADPH oxidase system.

Adenosine deaminase activity and superoxide formation during phagocytosis and membrane perturbation of macrophages.

During phagocytosis and membrane perturbation, mouse macrophages generate superoxide in direct proportion to their intracellular adenosine deaminase activity. It is proposed that since adenosine deaminase controls the amount of substrate available to xanthine oxidase, and the latter produces superoxide during turnover of its substrates, the purine salvage pathway is an important contributor to the superoxide requirement of macrophages. It is further proposed that this may be the basis for the mechanism of the association of adenosine deaminase deficiency with immunodeficiency.

Positive correlation between adenosine deaminase activity and superoxide formation during phagocytosis.

Phagocytosis and membrane perturbation in mouse macrophages results in an increased superoxide ion production which is in direct proportion to the concomitant increase in adenosine deaminase activity. Since adenosine deaminase activity controls the amount of substrate available to xanthine oxidase, and the latter produces superoxide during turnover of its substrates, it is proposed that the purine salvage pathway is an important source of the superoxide requirement of macrophages. It is further proposed that this may be the basis, at least in part, for the mechanism of the association of immunodeficiency with adenosine deaminase deficiency.

A discussion of some temporal characteristics of electroacoustic impedance bridges.

The purpose of this study was to describe an acoustic method for measuring temporal characteristics of electroacoustic impedance bridges, and to present data on the temporal responses of three widely used electroacoustic instruments. The potential effects of these instrument parameters on measured characteristics of the acoustic reflex are discussed.

Prediction of hearing sensitivity from acoustic reflexes in mentally retarded persons.

The ability of the sensitivity prediction from acoustic reflex (SPAR) technique to estimate hearing loss in mentally retarded subjects was investigated by comparing measured pure-tone thresholds determined through tangible-reinforcement operant-conditioning audiometry with predicted sensitivity from the SPAR procedure. Measurements were completed on a total of 32 retarded individuals having hearing levels ranging from normal to profound hearing loss. With minor exception, absences of the acoustic reflex were always accompanied by clearly abnormal tympanometry findings in the probe ear; therefore, the problem of unexplained absences of the reflex appeared to be minimal. Hearing loss never was present in those subjects for which SPAR predicted normal hearing, and the SPAR procedure never failed to detect an existing sensorineural hearing loss. On the other hand, there was some tendency for hearing loss to be predicted in normal-hearing subjects and for extent of hearing loss to be overestimated in subjects having a hearing loss.

Acoustic reflex latency as a function of frequency and intensity of eliciting stimulus.

The purpose of the present study was to examine the functional between acoustic reflex (AR) latency and the intensity and frequency of the eliciting stimulus. AR latency was determined at various intensities for 500 Hz and 300 Hz pure tones, and for wide-band noise. The results of the study indicated that AR latency decreased as stimulus intensity increased for all stimuli; the exact nature of the relationship depended on the stimulus, however. Latency differences between the stimuli at a given sound pressure level tended to disappear at higher presentation levels. Of particular interest was the dependency of inter- and intrasubject variability on parameters of the eliciting stimulus. The data do no indicate that AR latency is mediated solely by the loudness of the eliciting stimulus.

Cosolvent-buffer mixtures as models for the cytoplasmic mileu: the enzymology of adenosine aminohydrolase.

Adenosine aminohydrolase from calf intestinal mucosa is sensitive to changes in its environment produced by small mole fractions of dimethylsulfoxide (DMSO). At a mole fraction of 0.1 where the dielectric constant is lowered from that of 78 of neat water to about 76.5, Vmax was reduced by 65% and affinity for substrate (adenosine) and the two competitive inhibitors, insine and N6-benzyladenosine, was decreased markedly. However, this decreased affinity was such that Ki/Km remained virtually constant for both inhibitors. DMSO itself showed the kinetics of a mixed inhibitor with Ki decreasing with increasing mole fraction. This cosolvent also decreased the heat stability of the enzyme which suggests that enzyme conformation is altered by DMSO. Comparison of data in the presence of DMSO with previously obtained data with dioxane shows that heat stability as well as Vmax, at a given value of dielectric constant, is independent of the amount or nature of cosolvent used to achieve that dielectric constant. However, cosolvent induced changes in Ki indicate that colligative as well as dielectric constant effects contribute to the observed changes in kinetic behavior. These experiments may be considered as models for the behavior of enzymes in the medium of lowered dielectric constant expected in the vicinity of cytoplasmic membranes. The results indicate that in such an environment, adenosine aminohydrolase would be expected to be less efficient a catalyst, but equally susceptible to product inhibition, as compared to media of dielectric constant approaching that of water.

An artifact in acoustic reflex measurement: some further observations.

This study was designed to clarify characteristics of an artifact that has been reported to be a potential source of misleading information when determing acoustic reflex thresholds elicited by low-frequency tones. The study was conducted in two parts. Experiment 1 was concerned with an investigation of acoustic interactions in a sealed cavity between the probe tone from a commercial electroacoustic impedance bridge and interfering tones of various frequencies. Experiment 2 consisted of measurements of sound pressure levels in the sealed external ear canal of the probe ear when the contralateral ear was stimulated by air-conducted pure tones. The results indicated that acoustic reflex thresholds in 250-Hz tones probably cannot be determined for most persons unless special measures are taken to prevent the artifact. The artifact should not occur when the eliciting stimulus is 500 Hz, however.