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PubMed1996

Effect of land-based and water-based fitness programs on the cardiovascular fitness, strength and flexibility of women aged 65-75 years.

The purpose of this study was to determine the effectiveness of a generalized water-based exercise program (WBE) compared to a land-based exercise program (LBE) on improving cardiorespiratory fitness, body composition, forward trunk flexion and strength measurements of elderly women aged 70 +/- 3.2 years (mean +/- SD). Forty-one healthy, sedentary women were selected to participate in the study and were randomly assigned to the LBE or WBE. The 2 groups exercised for 12 weeks, 3 times/week for 45 min. Fitness testing was done before, during and after training, and included measurements of peak aerobic power (VO2 peak), forward trunk flexion, sum of skinfolds, grip strength, curl-ups and push-ups. Between the tests performed before and after training, there were significant improvements in VO2 peak in both groups (p < 0.05) with no significant differences between the groups (p > 0.05). The LBE group also showed a significant improvement in the total number of curl-ups performed (p < 0.05). There were no significant differences in trunk forward flexion, total (right plus left) grip strength, push-ups, waist to hip ratio, sum of skinfolds or body mass index between the tests performed before and after training over time within groups or between groups (p > 0.05). The results show that general exercise interventions resulted in improvements in cardiovascular fitness (for both groups) and abdominal endurance (in the LBE only), but the two exercise programs used were not specific enough or long enough to cause improvements in muscular strength, flexibility or body composition. Furthermore, except for changes in abdominal endurance, the type of exercise venue (land vs. water) did not have a significant effect on the results obtained.

Aged↗
PubMed1988

Pattern of psychological fitness as related to pattern of physical fitness among older adults.

The purpose of the present study was to investigate psychological fitness as well as physical fitness among late middle-aged normal men and women before, during, and after a 12-wk. physical activity program. Heart-rate of each subject was measured on a graded treadmill four times, and four psychological measures were taken: self-esteem, body-image, trait-anxiety, and well-being. Improvement of fitness was gradual and significant for both sexes, whereas no effects of time or sex were found on the first three psychological measures. Significant differences in pattern of change between women and men on well-being confirm previous findings that women report more depression and less satisfaction than men and thus are more sensitive to change.

Anxiety↗
PubMed1996

The effects of superstructure fit and loading on individual implant units: Part 2. The effects of loading a superstructure with varying degrees of fit.

This study investigated force transmission in an implant supported bridge with varying degrees of fit. The project utilised an in vitro model of five implant fixtures mounted linearly and rigidly. These supported a well-fitting cast gold superstructure via implant abutments fitted with strain gauges so as to function as force transducers. Gaps of 10-110 microns were created at the middle and one terminal abutment and loads of 50N applied over the cantilever and 230N between the terminal abutments. Force distribution was uneven, compression, tension and torque observed, and loading of the cantilever noted to generate large forces.

Bite Force↗
PubMed1998

Supplemental fitness activities and fitness in urban elementary school classrooms.

BACKGROUND: The physical activity levels of US children are declining. Opportunities for physical activity within city schools are constrained by time and space limits. This study determined whether a supplemental program of physical activity would significantly alter the fitness levels of low-income, minority, urban elementary schoolchildren. METHODS: Ninety-nine students from two Cleveland Public Schools served as subjects. One school received a 15-week intervention program where teams of two medical students met with urban elementary schoolchildren three times a week for physical activity sessions. The other school served as a control and received no supplemental activity other than a regularly scheduled physical education class held once a week. We obtained field measurements of skinfold thickness, heart rate response to submaximal exercise, and sit and reach flexibility. RESULTS: The supplemental activity group showed significant improvements in flexibility, body composition, and heart rate response to submaximal exercise. CONCLUSIONS: This investigation indicates that a program of fitness activities conducted within the classroom can significantly improve levels of fitness in urban elementary schoolchildren.

Analysis of Variance↗
PubMed2004

Molecular basis of fitness loss and fitness recovery in vesicular stomatitis virus.

Viral populations subjected to repeated genetic bottleneck accumulate deleterious mutations in a process known as Muller's ratchet. Asexual viruses, such as vesicular stomatitis virus (VSV) can recover from Muller's ratchet by replication with large effective population sizes. However, mutants with a history of bottleneck transmissions often show decreased adaptability when compared to non-bottlenecked populations. We have generated a collection of bottlenecked mutants and allowed them to recover by large population passages. We have characterized fitness changes and the complete genomes of these strains. Mutations accumulated during the operation of Muller's ratchet led to the identification of two potential mutational hot spots in the VSV genome. As in other viral systems, transitions were more common than transversions. Both back mutation and compensatory mutations contributed to recovery, although a significant level of fitness increase was observed in nine of the 13 bottlenecked strains with no obvious changes in the consensus sequence. Additional replication of three strains resulted in the fixation of single point mutations. Only two mutations previously found in non-bottlenecked, high-fitness populations that had been adapting to the same environment were identified in the recovered strains.

Animals↗
PubMed1999

[Improvement of hearing aid fitting with digital aids and new fitting strategies].

Hearing aids with digital signal processing demonstrate a large dynamic range with negligible distortion and no significant inherent noise. Furthermore, many acoustic parameters allow the compensation of even severe hearing loss, and the adjustment is extremely accurate. However, the new hearing aid generation not only requires computerized fitting, but also an experienced examination with new integrated fitting procedures. In addition to in situ measurement, the hearing aid fitting should include not only the Freiburg speech test, but also the Göttingen sentence test and the monosyllable rhyme test with different noises, for example the Fastl noise or the Döring babble noise. Loudness scaling with different methods is particularly important.

Analog-Digital Conversion↗
PubMed1997

Quantitative fit testing techniques and regulations for tight-fitting respirators: current methods measuring aerosol or air leakage, and new developments.

Until a few years ago, only two quantitative fit testing (QNFT) techniques were available and accepted by U.S. Occupational Safety and Health Administration (OSHA) regulations. In the 1980s and 1990s, several new and fundamentally different QNFT methods were developed. Two of the newer methods are commercially available and are accepted by OSHA as suitable alternatives. In this article the principles of operation of the OSHA-accepted and of some newly developed but not yet approved QNFT techniques are explained, and each technique's major advantages and disadvantages are pointed out. Emphasis is given to negative-pressure air-purifying respirators, as they are in most frequent use today. The requirements and recommendations for fit testing positive-pressure respirators are discussed as well. Finally, the presently available QNFT standards and regulations are summarized to assist the user in making fit testing decisions.

Aerosols↗
PubMed2006

Bone ingrowths to press-fit and loose-fit implants: comparisons between titanium and hydroxyapatite.

The aim of this study was to investigate whether the coating of titanium (Ti) implants with hydroxyapatite (HA) might create a better fixation when titanium implants are implanted into a gap. In each of 16 rats, the medullary cavity of both femurs was entered by an awl from the trochanteric area. With steel burrs it was successively reamed to a diameter of 1.5 mm. In a random manner the proximal part of the cavity in half of the bones was reamed once again to a diameter of 2.0 mm. Nails with a diameter of 1.5 mm and a length of 34 mm were then inserted into the medullary cavity of these bones with press fit at the distal half and a gap to the bone in the proximal half. In the remaining bones the whole medullary canal was reamed to a diameter of 2.0 mm, and nails with a diameter of 2.0 mm and a length of 34 mm were introduced. In all cases, either a pure Ti nail or a Ti nail entirely plasma sprayed with HA was used in a random manner. The surface roughness of the pure Ti was characterized by Ra 2.6 microm and Rt 22 microm. Ra of HA was 7.5 microm and Rt 52 microm. At sacrifice after 16 weeks, both femurs were dissected free from soft tissues and then immersed in fixative. A specimen slice of about 5 mm in thickness was prepared from the subtrochanteric region with a water-cooled band saw. Sample preparation for undecalcified tissue followed the internal guidelines at the laboratories of the Department of Biomaterials/Handicap Research. Generally, bone contact to the nails with HA coating was more predictable than was bone contact to the Ti nails. But due to rather large variations in bone contact between the samples, statistical analyses revealed non-significant differences between the 4 groups (p = 0.083). There were no significant differences between Ti and HA coated nails of 2.0 mm (p = 0.633), nor between Ti and HA coated nails of 1.5 mm (p = 0.924). The pooled values for the 2.0 mm nails showed significantly higher bone bonding contact than the pooled values of the 1.5 mm nails (p = 0.011). Our results, then, indicate that bone bonding contact to implants with a loose fit insertion is less predictable than in press fit insertion, and HA coating seemed to be more predictable than pure Ti. However, due to large variations between the samples, the differences did not reach significant levels.

Animals↗
PubMed2002

A diffusion model account of response time and accuracy in a brightness discrimination task: fitting real data and failing to fit fake but plausible data.

A brightness discrimination experiment was performed to examine how subjects decide whether a patch of pixels is "bright" or "dark," and stimulus duration, brightness, and speed versus accuracy instructions were manipulated. The diffusion model (Ratcliff, 1978) was fit to the data, and it accounted for all the dependent variables: mean correct and error response times, the shapes of response time distributions for correct and error responses, and accuracy values. Speed-accuracy manipulations affected only boundary separation (response criteria settings) in the model. Drift rate (the rate of accumulation of evidence) in the diffusion model, which represents stimulus quality, increased as a function of stimulus duration and stimulus brightness but asymptoted as stimulus duration increased from 100 to 150 msec. To address the argument that the diffusion model can fit any pattern of data, simulated patterns of plausible data are presented that the model cannot fit.

Attention↗
PubMed2006

Local heterozygosity-fitness correlations with global positive effects on fitness in threespine stickleback.

The complex interactions between genetic diversity and evolution have important implications in many biological areas including conservation, speciation, and mate choice. A common way to study these interactions is to look at heterozygosity-fitness correlations (HFCs). Until recently, HFCs based on noncoding markers were believed to result primarily from global inbreeding effects. However, accumulating theoretical and empirical evidence shows that HFCs may often result from genes being linked to the markers used (local effect). Moreover, local effect HFCs could differ from global inbreeding effects in their direction and occurrence. Consequently, the investigation of the structure and consequences of local HFCs is emerging as a new important goal in evolutionary biology. In this study of a wild threespine stickleback (Gasterosteus aculeatus) population, we first tested the presence of significant positive or negative local effects of heterozygosity at 30 microsatellites loci on five fitness components: survival, mating success, territoriality, length, and body condition. Then, we evaluated the direction and shape of total impact of local HFCs, and estimated the magnitude of the impacts on fitness using regression coefficients and selection differentials. We found that multilocus heterozygosity was not a reliable estimator of individual inbreeding coefficient, which supported the relevance of single-locus based analyses. Highly significant and temporally stable local HFCs were observed. These were mainly positive, but negative effects of heterozygosity were also found. Strong and opposite effects of heterozygosity are probably present in many populations, but may be blurred in HFC analyses looking for global effects only. In this population, both negative and positive HFCs are apparently driving mate preference by females, which is likely to contribute to the maintenance of both additive and nonadditive genetic variance.

Animals↗
PubMed1978

Overexertion injuries in keep-fit athletes. A study on overexertion injuries among non-competitive keep-fit athletes.

During three years, 274 exertion injuries in middle-aged keep-fit athletes were collected. A keep-fit athlete was a person, who regularly took part in noncompetitive sports activities. Exertion injury was a nontraumatic pain syndrome in the musculo-skeletal system. In the material, there were 35 women and 239 men. Most of them were 30--39 years old. Most exertion injuries took place in July, August, and September. About 80% of the patients were joggers. 80% of them had been training regularly for more than one year. At the moment of occurence of the symptoms, 68% of the patients trained 3--5 times a week. Joggers ran approx. 40 km/week. About 30% of the injuries took place in the knee, 24% in the ankle, heel and foot, 17% in the leg, and 9% in the achilles tendon. Almost one fifth of the pain syndromes were chronic in nature. The majority responded well to rest and to conservative treatment. Fifteen cases were treated surgically. Most of the exertion injuries were typical exertion syndromes seen also in competitive athletes. Others were degenerative changes, organic anomalies etc., which revealed their first symptoms during regular keep-fit activities.

Adolescent↗
PubMed2006

[The tasks of the ENT specialist by hearing aid fitting. Part 2: checking the fit, subjective satisfaction, ear mold and hearing aid].

The second part of this series deals with the tasks of the ENT-specialist, who must not endorse the prescription before making sure that the hearing aid recommended by the acoustician will bring sufficient hearing improvement, and that the suggested hearing aid is suitable. The report and audiograms of the acoustician must be compared to his own results, and a check of whether at least three hearing aids from different companies have been compared must be made. The primary aim of patient satisfaction can be checked by means of the "Oldenburger Inventar" (Oldenburg questionnaire), which determines the improvement of hearing ability in quiet and noise, and of auditory localization. Since the otoplastic substantially effects the amplification of the hearing aid, the ENT specialist should make sure that it does not produce feedback, that it has a second boring, and, in case of need, a Libby horn. He should also consider whether an open fitting would be more appropriate. A free-field measurement--with and without noise--shows whether the dB(opt) has been reached. The in situ measurement and the loudness rating by the Würzburger Hörfeld (Wuerzburg auditory field) are of great help in detecting fitting errors. Additional procedures, such as auditory speech training, lip reading, or technical devices, for instance FM-communication or a light alarm clock, are often employed in elderly patients.

Correction of Hearing Impairment↗
PubMed1999

Use of a loudness model for hearing aid fitting: III. A general method for deriving initial fittings for hearing aids with multi-channel compression.

A model for predicting loudness for people with cochlear hearing loss is applied to the problem of the initial fitting of multi-channel fast-acting compression hearing aids. The fitting is based entirely on the pure tone audiogram, and does not require measures of loudness growth. One constraint is always applied: the specific loudness pattern evoked by speech of a moderate level (65 dB SPL) should be reasonably flat (equal loudness per critical band), and the overall loudness should be similar to that evoked in a normal listener by 65-dB speech. This is achieved using the 'Cambridge' formula. For hearing aids where the compression threshold in each channel can be set to a very low value, an additional constraint is used: speech with an overall level of 45 dB SPL should be audible over its entire dynamic range in all frequency channels from 500 Hz up to about 4 kHz. For hearing aids where the compression thresholds cannot be set to very low values, a different additional constraint is used: the specific loudness pattern evoked by speech of a high level (85 dB SPL, and with the spectral characteristics of shouted speech) should be reasonably flat, and the overall loudness should be similar to that evoked in a normal listener by 85-dB speech. For both cases, compression ratios are limited to values below 3. For each of these two cases, we show how to derive compression ratios and gains, and for the first case, compression thresholds, for each channel. The derivations apply to systems with any number of channels. A computer program implementing the derivations is described. The program also calculates target insertion gains at the centre frequency of each channel for input levels of 50, 65 and 80 dB SPL, and target gains at the eardrum measured relative to the level at the reference microphone of a probe microphone system.

Auditory Threshold↗
PubMed2001

Do fits really beget fits? The effect of previous epileptic activity on the subsequent induction of the tetanus toxin model of limbic epilepsy in the rat.

The effect of pretreatment with either tetanus toxin (in ventral hippocampus) or kainic acid (into dorsal hippocampus, with or without suppression of seizures by phenobarbital) on the subsequent development of epilepsy in rats injected with tetanus toxin (into ventral hippocampus) has been studied. Both treatments advanced the timing of the development of the subsequent epilepsy by a few days but did not affect the severity of the syndrome. The fits stopped after 3 weeks in all the rats but recurred in 6 of 20 of those given kainic acid, with or without phenobarbital, but not in those given only tetanus toxin. It is concluded that while fits make the brain more sensitive to a further epileptogenic stimulus they do not themselves increase their severity or persistence. It is the destruction of the CA3/4 area of the hippocampus which results in this advance and in the predisposition to permanent epilepsy.

Animals↗
PubMed1997

Isomerization of the free enzyme versus induced fit: effects of steps involving induced fit that bypass enzyme isomerization on flux ratios and countertransport.

In a single-substrate-single-product enzyme reaction, "counter transport', which indicates that the ratio of the forward to the reverse fluxes is less than that expected from the Independence Relationship, is regarded as strong evidence for the free enzyme existing in two states, one of which combines with the substrate and the other with the product, with a slow isomerization between the two conditions. To account for positive and negative co-operativity, found with some enzymes, additional induced-fit reactions bypassing at least part of the isomerization have been proposed. The effects of such additional steps have been examined, using two models: in one, (a), the enzyme passes through an intermediate state during its isomerization, and both substrate and product may react with this state to give rise to the binary complexes; in the other, (b), the substrate may react with the enzyme as soon as the product is released and similarly with the reverse reaction, the isomerization thereby being bypassed completely. In the presence of such additional steps, the following can be concluded. (i) The data should be analysed in terms of the flux ratios, rather than observation of the amount of countertransport. (ii) The additional bypassing steps markedly change the pattern of dependence of the flux ratio on substrate and product concentrations. At high substrate and product concentrations, the ratio remains very dependent on how far the reaction is from equilibrium, and the kinetics are asymmetric. (iii) The mechanism causing the flux ratio to be less than that given by the Independence Relationship differs from that previously described, in that, at least in part, it arises from a 1:1 exchange between substrate and product. (iv) Despite this novel mechanism, there must be two states of the enzyme, combining respectively with substrate and product, and these must not be in rapid exchange. Thus countertransport remains very strong evidence for the existence of two such states. It is no longer a requirement that the enzyme states should be linked by an isomerization step. (v) Under no conditions can the flux ratio exceed that given by the Independence Relationship. (vi) Under unusual conditions the isomerization of the enzyme in model (b) may be undetectable by steady-state kinetics. (vii) Measurements of the coefficients in the flux ratio equations enable limits to be set to certain ratios of the rate constants. In addition to these conclusions, methods are described for (viii) analysing flux ratio data for the presence of induced fit steps and (ix) determining flux ratios from induced transport curves. The derivation of steady state-velocity equations show that: (x) both models may give rise to positive and negative 'co-operativity' and sigmoid substrate-velocity curves, but that, under conditions giving rise to sigmoid curves, the deviation of the flux ratio from that required by the Independence Relationship may be difficult to demonstrate because of the asymmetry of the system. Under all conditions the fluxes at equilibrium should obey hyperbolic kinetics.

Algorithms↗
PubMed2006

Human immunodeficiency virus type 1 coreceptor switching: V1/V2 gain-of-fitness mutations compensate for V3 loss-of-fitness mutations.

Human immunodeficiency virus type 1 (HIV-1) entry into target cells is mediated by the virus envelope binding to CD4 and the conformationally altered envelope subsequently binding to one of two chemokine receptors. HIV-1 envelope glycoprotein (gp120) has five variable loops, of which three (V1/V2 and V3) influence the binding of either CCR5 or CXCR4, the two primary coreceptors for virus entry. Minimal sequence changes in V3 are sufficient for changing coreceptor use from CCR5 to CXCR4 in some HIV-1 isolates, but more commonly additional mutations in V1/V2 are observed during coreceptor switching. We have modeled coreceptor switching by introducing most possible combinations of mutations in the variable loops that distinguish a previously identified group of CCR5- and CXCR4-using viruses. We found that V3 mutations entail high risk, ranging from major loss of entry fitness to lethality. Mutations in or near V1/V2 were able to compensate for the deleterious V3 mutations and may need to precede V3 mutations to permit virus survival. V1/V2 mutations in the absence of V3 mutations often increased the capacity of virus to utilize CCR5 but were unable to confer CXCR4 use. V3 mutations were thus necessary but not sufficient for coreceptor switching, and V1/V2 mutations were necessary for virus survival. HIV-1 envelope sequence evolution from CCR5 to CXCR4 use is constrained by relatively frequent lethal mutations, deep fitness valleys, and requirements to make the right amino acid substitution in the right place at the right time.

Amino Acid Sequence↗
PubMed1989

Preliminary results of an off-the-shelf press-fit stem. The anthropometric total hip femoral component using exact-fit principles.

The use of custom-manufactured femoral prostheses as part of routine total hip arthroplasty (THA) has been suggested. However, there are several disadvantages, including possible inaccuracy of fit, inadequate instrumentation, and high cost. A series of 28 THAs (including 18% for revision of failed, cemented THA) using a press-fit prosthesis of contemporary design were investigated. The average follow-up period was 28 months (range, 12-49 months). Clinical results were overall very good, even in revision cases. Roentgenographic changes included rapid femoral remodeling, which may increase component stability. Given the clinical and roentgenographic results obtained in this complex-problem patient population, it is difficult to justify the use of custom femoral components in routine THA.

Adult↗
PubMed1995

The effects of superstructure fit and loading on individual implant units: Part I. The effects of tightening the gold screws and placement of a superstructure with varying degrees of fit.

This in vitro study investigated forces associated with the assembly of rigidly mounted Nobelpharma implants and a 'passively' fitting cast gold superstructure. The effects of modifying the fit by 10-110 micrometers were also investigated. Measurements were made using linear resistance strain gauges mounted longitudinally on the abutments. Tightening the gold screws produced high compressive strains. These were unevenly distributed, and inconsistent. Tensile strains were produced by gaps as small as 10 micrometers between the superstructure and an abutment while the ability of a torque of 10 N-cm in the gold screw to close the gaps was dependent on their dimensions and locations.

Dental Abutments↗