Cost-effectiveness of assertive community treatment teams

The long cane can be used as a mobility aid for visually handicapped people. According to a questionnaire completed by Japanese cane users, it seems they are not always satisfied with using long canes for a variety of reasons. In this study, hand-transmitted vibration from the long cane due to tapping the ground was measured because an exposure to repeated shock-type tapping vibration may affect the hand-arm system. A sighted female wearing a blindfold participated. The measurement was carried out in different conditions with three different ground materials both indoor and outdoors. The vibration at three axes of the cane grip and one axis at the wrist were measured. The pinch forces between an index finger and the grip were also measured using a strain gauge in order to observe how the vibration characteristics depend on the changing forces. Measurement, evaluation and assessment were based on the International Standard (ISO 5349). The estimated daily exposure time and the transmissibility were obtained in order to investigate the severity of the hand-transmitted vibration caused by the long cane. It was found that the characteristics of tapping vibration depend on different measurement conditions and the vibration might be associated with a health risk over a long life span.     

Vibrations as an experimental factor affecting intestinal resorption

The authors treated white rats daily at one and the same time for a period of one hour with vibrations. One of the groups of animals were treated with vibrations and examined after that, but the other two groups were treated respectively for 45 and 90 days. Examination was carried out during vibration, immediately after that and three hours after the vibrations. They used the method of the turned bags of Wilson and Waisman, by means of which they checked the resorption of glucose through the intestinal wall in vitro, it was established that during continuous vibration action the values of the resorption glucose were statistically lower than those of the control group. There were statistically significant differences in the values of the resorbed glucose in the subgroups examined during the vibration immediately and there hours after that. The authors discuss the obtained results in the light of the current concepts for the action of vibrations as a stress factor and their influence on intestinal resorption.     

AIDS caregiving and health among midlife and older women

OBJECTIVES: This study investigated changes in finger circulation after different durations of exposure to hand-transmitted vibration. METHODS: Finger skin temperature (FST), finger blood flow (FBF), and finger systolic blood pressure (FSBP) were measured in the middle fingers of both hands of 10 healthy men. Finger vascular resistance was also estimated. The right hand was exposed for 7.5, 15, and 30 minutes (static load 10 N) to 125-Hz vibration (root-mean-square acceleration 87 m/s2). Static load only was used as a control. Finger circulation was measured before the vibration and static load exposure and at fixed intervals during exposure and a 45-minute recovery period. RESULTS: No significant changes were found with the static load. The FST and FSBP did not change significantly during vibration exposure, whereas vibration produced significant reductions in FBF and increases in vascular resistance at each duration when compared with preexposure and contralateral (non-vibrated) finger values. Temporary vasodilation occurred in the vibrated finger immediately after each vibration exposure. Recovery was complete for FBF and vascular resistance after the 7.5-minute vibration, whereas a progressive FBF reduction occurred in both the vibrated and the nonvibrated fingers after 15- and 30-minute exposure. The longer the duration of vibration exposure, the stronger the vasoconstriction in the vibrated finger during recovery. CONCLUSIONS: Vasoregulatory mechanisms mediated by both intrinsic (local) and extrinsic (neural or endocrine) control systems seem to be related to digital circulatory changes during 125-Hz vibration. It is concluded that, not only the frequency and magnitude of vibration, but also its duration contributes to the reaction of the digital vessels to acute vibration.     

Blood pressure measurement. Criteria employed in scientific articles published in Brazilian journals]

OBJECT: To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects. METHOD AND DESIGN: Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s2, 60 Hz), noise [90 dB(A)] and both, respectively. The subject's right hand was placed on the plate of a vibrator and the right ear exposed to noise via headphones. Subjects were exposed to vibration and/or noise for 3 min and after a 1-min pause the exposure was repeated five times. Hearing thresholds at 1, 4 and 6 kHz were measured during the time periods before, between (during pauses) and after exposure. RESULTS: Exposure to vibration alone caused almost no hearing threshold changes at every frequency tested. But exposure to noise or a combination of vibration and noise caused a significant increase in TTSs at 4 and 6 kHz. Moreover, exposure to a combination of vibration and noise caused significantly higher TTSs than exposure to noise at 4 and 6 kHz. CONCLUSION: The present results demonstrate the combined effects of hand-arm vibration and noise can enhance exposure to hand-arm vibration and noise can enhance the TTS of hearing more than noise exposure, though hand-arm vibration alone may hardly affect TTS.     

Acceleration of fetal head induced by vibration of maternal abdominal wall in sheep

OBJECTIVE: The human body is often exposed to significant vibration stress in the workplace, at home, and during recreational activities. The current study was designed to evaluate whether low- to midfrequency vibrations present at the extraabdominal wall would be attenuated across this wall and what the levels of exposure would be once these vibrations reached the fetal head. STUDY DESIGN: Four pregnant sheep were instrumented with acceleration transducers to obtain acceleration levels at the extraabdominal and intraabdominal walls and at the fetal head. Sine-wave vibration stimulation was applied over a frequency range of 3 to 150 Hz at a constant acceleration level of 2.5 m/sec2 (root-mean-square). RESULTS: Vibration of the extraabdominal wall resulted in a frequency-dependent rise in vibration levels at the intraabdominal wall, from 4% to 140% of the input level. At the fetal head a broad peak in response was noted between 6 and 12 Hz, but the overall levels never exceeded 4% of the input level. CONCLUSION: Fetal exposure to localized vibratory stimulation of the maternal abdomen is maximal in the range of 6 to 12 Hz.     

Octahydro-bispyridinium-4-pyrono chloride]

C1r levels in normal adults were determined by electroimmunoassay. The 95 per cent range was 71-133 per cent of a normal reference pool. C1r values were well correlated to the levels of C1q (r = 0.708) and of C1s (r = 0.768). The interplate variation of the method on double determinations was 3.4 (SD). C1r values in normal sera not appreciably affected by storage at room temperature or by repeated freezing and thawing. The C1r antigen in EDTA plasma was found to be labile.     

Discomfort judgements of translational and angular whole-body vibrations

In a previous series of experiments the subjective intensities of translational (Z-axis) and angular (roll, pitch, and yaw) vibrations were compared, using a psychophysical matching technique. To test the validity and generality of the matching results, an independent set of similar data was obtained in the present experiment, using the method of category production. Seated subjects set levels of translational vibrations, in the X-, Y-, and Z-axes, and angular vibrations, in roll and pitch, that they judged to be "uncomfortable" on a scale of vibration discomfort. Frequencies of 2.5, 3.15, 4.0, 5.0, 6.3, and 8.0 Hz were presented in each vibration direction. As frequency increased the mean acceleration judged to be uncomfortable increased for Y-axis and roll vibrations, decreased for Z-axis vibrations, and was essentially constant for X-axis and pitch vibrations. The Y- and Z-axis results correspond well to equal intensity contours in existing vibration exposure criteria, and the roll results show good agreement with data from the roll matching experiment. The X-axis and pitch results are similar to the results from the pitch matching experiment and indicate the importance of the backrest in determining the effects of X-axis translational vibrations and angular vibrations in pitch.     

Studies on the transmission of vibrations in human organism exposed to low-frequency whole-body vibration

Investigations were carried out in a group of 20 males with a definite morpho-physiological type, at two selected ranges of acceleration values chosen according to ISO criteria in the range of 2-20 Hz. In the subjects exposed to vibration the values of vibration acceleration were measured in different points along the spine at the levels of S3, L3, Th7, C3 and at the vertex. The investigations demonstrated that the frequency is the parameter of crucial significance for the propagation of vibrations in the human organism. Vibration within the frequency range up to 12 Hz affects the whole human organism, while the vibrations above 12 Hz have only a local effect.     

Inhibition of beta-adrenergic desensitization by KCa channels in human trachealis

We examined the reduced responsiveness to beta-adrenergic receptor agonists (beta-agonists) after exposure to beta-agonists, and the mechanisms underlying this phenomenon in isolated human tracheal smooth muscle, using isometric tension records to test the hypothesis that repeated inhalation of beta-agonists leads to reduced responsiveness to beta-agonists. The inhibitory effects of isoproterenol (ISO) on contraction by spasmogens participating in asthma attacks diminished markedly after continuous exposure to ISO (0.0003 to 3 microM) for 45 min; moreover, when ISO was repeatedly applied for 10 min to tissues precontracted by methacholine every 30 min, the relaxant effects of ISO gradually attenuated after these repeated applications. In contrast, reduced beta-adrenergic relaxation after continuous and repeated exposure to agonists did not occur when tissues were preincubated with 2 microg/ ml cholera toxin (CTX), which irreversibly activates guanosine triphosphate (GTP)-binding protein (Gs) coupled with beta-adrenergic receptors, for 6 h. However, the CTX inhibition disappeared in the presence of iberiotoxin, a selective inhibitor of large conductance Ca2+-activated K+ (KCa) channels. Our results demonstrate that continuous and repeated exposure to beta-agonists leads to beta-adrenergic desensitization, and that activation of KCa channels by Gs prevents this desensitization.     

Sound and vibration sensitivity of VIIIth nerve fibers in the frogs Leptodactylus albilabris and Rana pipiens pipiens

1. Responses of 73 fibers to dorso-ventral vibration were recorded in the saccular and utricular branchlets of Rana pipiens pipiens using a ventral approach. The saccular branchlet contained nearly exclusively vibration-sensitive fibers (33 out of 36) with best frequencies (BFs) between 10 and 70 Hz, whereas none of the 37 fibers encountered in the utricular branchlet responded to dorso-ventral vibrations. 2. Using a dorsal approach we recorded from the VIIIth nerve near its entry in the brainstem and analyzed responses to both sound and vibration stimuli for 65 fibers in R. pipiens pipiens and 25 fibers in Leptodactylus albilabris. The fibers were classified as amphibian papilla (AP), basilar papilla (BP), saccular or vestibular fibers based on their location in the nerve. Only AP and saccular fibers responded to vibrations. The AP-fibers responded to vibrations from 0.01 cm/s2 and to sound from 40 dB SPL by increasing their spike rate. Best frequencies (BFs) ranged from 60 to 900 Hz, and only fibers with BFs below 500 Hz responded to vibrations. The fibers had identical BF's for sound and vibration. The saccular fibers had BFs ranging from 10 to 80 Hz with 22 fibers having BFs at 40-50 Hz. The fibers responded to sound from 70 dB SPL and to vibrations from 0.01 cm/s2. 3. No differences in sensitivity, tuning or phase-locking were found between the two species, except that most BP-fibers in R. pipiens pipiens had BFs from 1.2 to 1.4 kHz, whereas those in L. albilabris had BFs from 2.0 to 2.2 kHz (matching the energy peak of L. albilabris' mating call). 4. The finding that the low-frequency amphibian papilla fibers are extremely sensitive to vibrations raises questions regarding their function in the behaving animal. They may be substrate vibration receptors, respond to sound-induced vibrations or bone-conducted sound.     

Design of Mechanical Viscous Dampers for Stay Cables

External dampers have been utilized in a number of cable-stayed bridges to suppress transverse cable vibrations. However, simple and accurate damper design recommendations that concurrently consider all important cable parameters are lacking. Previous efforts have been based on the idealization of cables as taut strings. In this paper, the governing differential equation for vibration of cables containing a viscous damper was first converted to a complex eigenvalue problem containing nondimensional cable parameters. Then, a parametric study was conducted involving repeated solutions of the eigenvalue problem for a wide range of nondimensional parameters. Based on the results of the parametric study, the effects of dampers on first mode vibration frequencies and first mode cable damping ratios were presented in nondimensional format. It is shown that for the range of parameters involved in most stay cables, the influence of cable sag is insignificant, whereas the cable bending stiffness can have a significant influence on the resulting cable damping ratios. Simplified nondimensional relationships are proposed for calculating damper-induced changes in the first mode cable damping ratios. Results of laboratory tests on a scaled model cable are compared with the estimated values using the formulation presented. Finally, example problems are presented for comparison with other relationships, and for the design of mechanical viscous dampers for suppression of cable vibrations including rain-wind induced vibrations.     

The unactivated form of the first component of human complement, C1

The first component of complement, C1, was isolated unactivated from human serum by repeated additions of di-isopropyl phosphorofluoridate during isolation. The unactivated subcomponents were also isolated, and evidence is given that the three subcomponents C1q, C1r and C1s account wholly for the activity of component C1 in serum. No evidence could be found for a fourth subcomponent, C1t. The approximate molar proportions of the subcomponents in serum are C1q/C1r/C1s = 1:2:2. Optimum activity by haemolytic assay was found at approximate molar proportions C1q/C1r/C1s of 1:4:4. No activity was found when subcomponents were assayed singly or in pairs, except for subcomponents C1q and C1s, which in molar ratio 1:4 gave 15-20% of the activity of the mixture C1q + C1r + C1s. The proteolytic activity of the isolated subcomponent C1s varied according to the method of activation used. Subcomponents C1q + C1r + C1s and C1q + C1s in the presence of antibody-antigen aggregates were activated and inactivated simultaneously, showing a peak of activity and subsequent loss of activity. Both reactions are probably due to proteolysis, and analysis of the peptide bonds split will be necessary to distinguish these two phenomena.     

Pharmacodynamics of vancomycin alone and in combination with gentamicin at various dosing intervals against methicillin-resistant Staphylococcus aureus-infected fibrin-platelet clots in an in vitro infection model

We compared the pharmacodynamic activities of vancomycin with or without gentamicin in an in vitro infection model with methicilin-resistant Staphylococcus aureus-infected fibrin-platelet clots. Infected fibrin-platelet clots (FPCs) were prepared with human cryoprecipitate, human platelets, thrombin, and the organism (approximately 10[9] CFU of MRSA-494/g) and were suspended with monofilament line in an infection model capable of simulating human pharmacokinetics. Antibiotics were bolused to simulate vancomycin regimens of 2 g every 24 h (q24h), 1 g q12h, 500 mg q6h, and continuous infusion (steady-state concentration of 20 microg/ml) and gentamicin regimens of 1.5 mg/kg of body weight q12h and 5 mg/kg once daily (q.d.). Model experiments were performed in duplicate over 72 h. FPCs were removed from the models in quadruplicate at 0, 8, 24, 32, 48, 72 h, weighed, homogenized, diluted, and plated to determine colony counts. The inoculum density at 72 h was used to compare bactericidal activities between the regimens. All regimens containing vancomycin significantly decreased the bacterial inoculum compared to the growth control (P < 0.001). Vancomycin monotherapy regimens were similar in bacterial kill regardless of dosing frequency. The addition of gentamicin (either q12h or q.d.) significantly improved the bactericidal activity of the vancomycin q6h, q12h, and q24h regimens (P < 0.001). The greatest reduction in bacterial density at 72 h (P < 0.001) and the most rapid rate of kill (time to 99.9% killing) were achieved with the regimen consisting of 2 g of vancomycin q24h plus gentamicin (q.d. or q12h).     

Automated segmentation of muscle fiber images using active contour models

Absorbed power (PAbs) during exposure to vertical whole-body vibration in a sitting posture was measured on 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0.5-1.4 m s(-2)) and frequency (2-100 Hz), body weight (54-93 kg) and, relaxed and erected upper body positions. Results show that PAbs was strongly related to the frequency of the vibration, peaking within the range of 4-6 Hz. The peak was predominantly located in the lower end of this range for females and for the relaxed sitting position. PAbs increased with acceleration level and body weight. Almost a ten-fold increase in PAbs was observed at the critical frequency when the vibration exposure was raised from 0.5 to 1.4 m s(-2). If risk assessment is based on the assumption that the amount of PAbs, independent of the frequency of the vibration, indicates a hazard, then the ISO-standard 2631 under- and overestimates the risk at frequencies below and above about 6 Hz, respectively. The results also indicate a need for differentiated guidelines for females and males. Many types of vehicles produce whole-body vibration with frequencies which coincide with the range where the highest PAbs was observed. PAbs is a 'new' concept for measurement of whole-body vibration exposure. Although not yet thoroughly evaluated, this measure may be a better quantity for risk assessment than those specified in ISO 2631 since it also takes the dynamic force applied to the human body into account.     

Three-Dimensional Analyses of Wave Barriers for Reduction of Train-Induced Vibrations

This paper explores the use of a three-dimensional finite-element analysis to model soil vibrations due to high-speed trains on bridges. Finite-element meshes include the bridge superstructure, bridge foundations, nearby building foundations, and piles. Wheel elements represented by appropriate mass, damping and stiffness factors were used to simulate a moving high-speed train. Along the mesh boundaries, absorbing boundary conditions were employed to avoid fictitious wave reflections. Isolation methods to reduce soil vibrations were investigated including construction of open and infilled trenches and soil improvement. Vibration isolation effects due to building foundations and piles were also studied. The finite-element results indicate that suitable axial stiffness between two simple beams can reduce vibration significantly, especially at a near-resonance condition. Operating with an appropriate train velocity to avoid resonance can be another way to reduce vibrations. Suitable mat foundations can significantly reduce soil horizontal vibration, but cannot isolate vertical vibration. Soil improvements near the bridge do not effectively attenuate low-frequency vibrations. Infilled and open trenches can isolate soil vertical vibration; however, their efficiency seems disproportionate to their cost.     

Lymphoedema and chylo-ascites; an unusual complication of lymphography

The authors carried out experiments on animals (40 white male rats) which were subjected to daily a two-hour action of the common vertical sinusoidal vibrations with a frequency of 20 Hr (I group) and 50 Hr (II group) with acceleration of 22,0 m/sec2 for a period of ten days (I group--A and second group--A) and 30 days (I group--B and II group--B). Histomorphological and histochemical methods were used and the authors found changes in microcirculation and structure of the intestinal wall manifested in the animals of the II group. The obtained results were in support of the clinical data on the disturbances in intestinal function in patients with vibration disease and corresponded to the experimental data on the occurrence of vascular and dystrophic changes in the internal organs under vibration action.     

Forced Vibrations of Single-Degree-of-Freedom Systems with Nonperiodically Time-Varying Parameters

A new exact approach for forced vibration analysis of single-degree-of-freedom (SDOF) systems with nonperiodically time-varying parameters (mass and stiffness) is presented. In this paper, the variations of mass and stiffness, relative to time, are described by the selection of suitable expressions such as power functions and exponential functions. More general cases, such as the variation of mass is described by an arbitrary continuous real-valued function and the variation of stiffness is expressed as a functional relation with the variation of mass and vice versa, are also considered in this study. Using appropriate functional transformation, the governing differential equations for vibrations of SDOF systems with nonperiodically time-varying parameters are reduced to Bessel’s equations or other solvable equations for several important cases. Thus, classes of exact solutions for the free and forced vibrations of SDOF systems with arbitrarily time-varying parameters (mass and stiffness) are obtained. Numerical examples show that the proposed procedure is a simple, efficient, and exact method.     

Haemodynamic changes in ipsilateral and contralateral fingers caused by acute exposures to hand transmitted vibration

OBJECTIVES: To investigate changes in digital circulation during and after exposure to hand transmitted vibration. By studying two frequencies and two magnitudes of vibration, to investigate the extent to which haemodynamic changes depend on the vibration frequency, the vibration acceleration, and the vibration velocity. METHODS: Finger skin temperature (FST), finger blood flow (FBF), and finger systolic pressure were measured in the fingers of both hands in eight healthy men. Indices of digital vasomotor tone-such as critical closing pressure and vascular resistance-were estimated by pressure-flow curves obtained with different hand heights. With a static load of 10 N, the right hand was exposed for 30 minutes to each of the following root mean squared (rms) acceleration magnitudes and frequencies of vertical vibration: 22 m.s-2 at 31.5 Hz, 22 m.s-2 at 125 Hz, and 87 m.s-2 at 125 Hz. A control condition consisted of exposure to the static load only. The measures of digital circulation and vasomotor tone were taken before exposure to the vibration and the static load, and at 0, 20, 40, and 60 minutes after the end of each exposure. RESULTS: Exposure to static load caused no significant changes in FST, FBF, or indices of vasomotor tone in either the vibrated right middle finger or the non-vibrated left middle finger. In both fingers, exposure to vibration of 125 Hz and 22 m.s-2 produced a greater reduction in FBF and a greater increase in vasomotor tone than did vibration of 31.5 Hz and 22 m.s-2. In the vibrated right finger, exposure to vibration of 125 Hz and 87 m.s-2 provoked an immediate vasodilation which was followed by vasoconstriction during recovery. The non-vibrated left finger showed a significant increase in vasomotor tone throughout the 60 minute period after the end of vibration exposure. CONCLUSIONS: The digital circulatory response to acute vibration depends upon the magnitude and frequency of the vibration stimulus. Vasomotor mechanisms, mediated both centrally and locally, are involved in the reaction of digital vessels to acute vibration. The pattern of the haemodynamic changes in the fingers exposed to the vibration frequencies used in this study do not seem to support the frequency weighting assumed in the current international standard ISO 5349.     

Respiratory responses to repeated prolonged exposure to 0.12 ppm ozone

Repeated exposure to high concentrations of ozone results first in augmentation (typically on the second day) and then attenuation of pulmonary response in humans. To determine the effects of repeated prolonged low-concentration ozone exposure, we exposed 17 healthy nonsmoking male subjects to 0.12 ppm ozone for 6.6 h on 5 consecutive days. Subjects were also exposed once to filtered air. Volunteers exercised at a ventilation of approximately 39 L/min for 50 min of each hour during the exposure. Spirometry, plethysmography, and symptom responses were obtained before, during, and after each exposure. Nasal lavage and aerosol bolus dispersion were obtained before and after exposure. Spirometry decreased and symptoms increased on the first day. Responses were less on the second day compared with those on the first day, and they were absent compared with control values on the subsequent 3 days of ozone exposure. Percent change in FEV1 after ozone exposure compared with that after air exposure averaged -12.79, -8.73, -2.54, -0.6, +0.18% for Days 1 to 5 of ozone exposure, respectively. FEV1 responses ranged from a zero to 34% decrease on Days 1 and 2. After each exposure, we determined the ratio of SRaw after inhaling a fixed dose of methacholine to SRaw after inhaling saline aerosol, as an index of airway responsiveness. Airway responsiveness was significantly increased after each ozone exposure. The mean ratios were 2.22, 3.67, 4.55, 3.99, 3.24, and 3.74 for filtered air and ozone Days 1 to 5, respectively. Symptoms of cough and pain on deep inspiration increased significantly on ozone Day 1 only.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparative study of cisapride and ranitidine at controlling oesophageal acid exposure in erosive oesophagitis

BACKGROUND: The severity of gastro-oesophageal reflux disease is generally considered to be related to the extent of oesophageal acid exposure. Current therapies include antisecretory and prokinetic agents. We compared two of these, ranitidine and cisapride, in their ability to lower oesophageal acid exposure in patients with erosive oesophagitis. METHODS: Seven patients with Savary-Miller's grade II-IV oesophagitis and with oesophageal contact time > or = 8% were studied. Mean lower oesophageal sphincter pressure was 4.6 mmHg. Oesophageal acid contact time was 25.6 +/- 5.6%. Each patient received ranitidine 150 mg b.d., ranitidine 150 mg q.d.s., or cisapride 10 mg q.d.s. in a randomized 3-way cross-over design. Intra-oesophageal pH was monitored during 24 h for each of these treatments in a controlled hospital environment, while consuming a high fat, high calorie diet. RESULTS: Cisapride and ranitidine at both doses decreased the acid contact time and the number of reflux episodes. However, a minority of patients treated with ranitidine, and none with cisapride, diminished their oesophageal acid contact time to a normal value of < 5%. No treatment significantly decreased nocturnal acid exposure. CONCLUSION: In patients with severe gastro-oesophageal reflux disease both cisapride and ranitidine demonstrably lower oesophageal acid exposure, but neither therapy predictably normalizes it.