Gender and age-related differences of dynamic balancing ability based on various stepping motions in the healthy elderly

This study was aimed at examining the gender and age-related differences of dynamic balance based on four stepping tests for the elderly. One hundred and eleven healthy subjects aged 60-85 were classified into four age groups (60-64, 65-69, 70-74, and 75-85) to examine age-related differences. They conducted stepping motions lasting 20-sec, including both-leg stepping right/left, both-leg stepping back/forth, one-leg stepping back/forth and one-leg stepping right/left. There were significant differences by age in all stepping parameters, with the decreasing number of steps and the increasing average ground connecting time during stepping with age. In males of age 60-69 and all females, the individual differences in the number of steps and the average connecting time during both-leg stepping (back/forth and right/left) were larger than those during one-leg stepping. Both-leg stepping was, therefore, considered to be a useful test to evaluate the individual differences of dynamic balance in the elderly. Individual differences in the number of steps by both-leg stepping tended to decrease with age. In males aged 70 or more, the individual differences in the number of steps and the average connecting time in both-leg stepping were smaller than those in one-leg stepping. The relationships between the results by both-leg stepping and those by one-leg stepping were poor. This may be because of the difference in body-posture stability during stepping motions. One-leg stepping is a useful test for the elderly who have difficulty with both-leg stepping because of its small center of gravity sway. The relationships between back/forth steps and right/left steps in both-leg or one-leg stepping were notable. Either of the stepping motions, therefore, can be selected to evaluate dynamic balance ability. There may be gender differences in the strategy to keep a stable body posture during both-leg stepping.     

The relationship between kinematic determinants of jump and sprint performance in division I women soccer players

The purpose of this study was to determine the relationship between measures of unilateral and bilateral jumping performance and 10- and 25-m sprint performance. Fifteen division I women soccer players (height 165 ± 2.44 cm, mass 61.65 ± 7.7 kg, age 20.19 ± 0.91 years) volunteered to participate in this study. The subjects completed a 10- and 25-m sprint test. The following jump kinematic variables were measured using accelerometry: sprint time, step length, step frequency, jump height and distance, contact time, concentric contact time, and flight time (Inform Sport Training Systems, Victoria, BC, Canada). The following jumps were completed in random order: bilateral countermovement vertical jump, bilateral countermovement horizontal jump, bilateral 40-cm drop vertical jump, bilateral 40-cm drop horizontal jump, unilateral countermovement vertical jump (UCV), unilateral countermovement horizontal jump, unilateral 20-cm drop vertical jump (UDV), and unilateral 20-cm drop horizontal jump (UDH). The trial with the best jump height or distance, reactive strength (jump height or distance/total contact time), and flight time to concentric contact time ratio (FT/CCT) was recorded to analyze the relationship between jump kinematics and sprint performance. None of the bilateral jump kinematics significantly correlated with 10- and 25-m sprint time, step length, or step frequency. Right-leg jump height (r = -0.71, p = 0.006, SEE = 0.152 seconds), FT/CCT (r = -0.58, p = 0.04, SEE = 0.176 seconds), and combined right and left-leg jump height (r = -0.61) were significantly correlated with the 25-m sprint time during the UCV. Right-leg FT/CCT was also significantly related to 25-m step length (r = 0.68, p = 0.03, SEE = 0.06 m) during the UDV. The combined right and left leg jump distance to standing height ratio during the UDH significantly correlated (r = -0.58) with 10-m sprint time. In comparison to bilateral jumps, unilateral jumps produced a stronger relationship with sprint performance.     

Ectopic testes in the Norway rat

Animals with ectopic testes, some unilateral (on either the right or left side) and some bilateral, have appeared in a colony of King-Holtzman rats. This heritable defect has been given the genetic symbol "ect." Females carrying the gene are unaffected by it. When such females are bred to apparently normal males, they produce no ect offspring. Since 25% of their F2 generation carry the gene, it is assumed it is autosomal recessive. Studies involving selective breeding for males with ectopic testes indicate that some males have genomes resistant to the expression of the ect gene and that the apparent thresholds essential to left side, right side, and bilateral expression appear to be a secondary control of the multifactorial type.     

Normal gait characteristics under temporal and distance constraints

Walking patterns of 53 males and 39 females, all in good health, were studied at slow, free, and fast speeds using a walkway system developed by the author. Three males and three females, also in good health, were then studied under constrained walking conditions such as rhythm constraint, speed coupled with constraint, walking up or down a slope, line stepping contraint, stepping onto a marked square, and starting/stopping of walking. In the first set of experiments, the following results were obtained. When increasing speed, the male had a tendency to increase step length and the female had a tendency to increase cadence. The relationships between the speed and the statistics of gait parameters, i.e. the coefficient of variation and the symmetry were examined. The data in this experiment were also applied to Grieve's gait equations which formulated the relationships between step frequency and speed, or between swing time and cycle time.In the second set of experiments the following results were obtained. Although rhythm constraint (induced by a metronome) resulted in no difference of gait between males and females, a difference did appear in the case of speed coupled with constraint. When walking up and down a slope, the ascent case showed a longer step length and a lower cadence compared with the descent. The idea of functional asymmetry, a supporting function of the left leg and a moving function of the right leg, is well accepted. However, in this study of the effect of line stepping constraints predominant right-left functional differences were found. The perturbation of gait when the subjects stepped onto a marked square resembling a force-plate was recorded quantitatively. With regard to the starting and stopping characteristics of walking, it was concluded that the two steps from starting and the three steps before stopping should be excluded from ordinary data due to their acceleration and deceleration properties.     

Bilateral linkage of monomorphic and dimorphic limb sizes in fiddler crabs

In this study, the subject of whether investment in one bilateral structure was linked to investment in the homologous bilateral opposite structure was investigated. Male fiddler crabs (genus Uca, family Ocypodidae) displayed strong bilateral claw differentiation of function and size, which are used for feeding (minor claw) or display/combat (major claw). Females had similar‐sized feeding claws. Linkage between claw size was investigated by estimating the deviations from an overall fitted regression of claw length to body size. The positive correlations of the deviations of claw size for major and minor claws of males and between right and left claws of females, relative to body size, suggested a linkage in investment between one claw and the corresponding claw on the other side of the body, for both monomorphic females and dimorphic males. A signal to send resources may be effectively gated to the claw complex, suggesting that positively correlated resources are allocated to both claws. Positive correlations were also found at the interspecific level. The fiddler crab model, described here, gives access to study the linkage in symmetric and asymmetric bilateral structures in the same species with a connection to the macroevolutionary level.     

Determination of functional strength imbalance of the lower extremities

The purposes of this study were (a) to determine whether a significant strength imbalance existed between the left and right or dominant (D) and nondominant (ND) legs and (b) to investigate possible correlations among various unilateral and bilateral closed kinetic chain tests, including a field test, and traditional isokinetic dynamometry used to determine strength imbalance. Fourteen Division I collegiate women softball players (20.2 +/- 1.4 years) volunteered to undergo measures of average peak torque for isokinetic flexion and extension at 60 degrees .s(-1) and 240 degrees .s(-1); in addition, measures of peak and average force of each leg during parallel back squat, 2-legged vertical jump, and single-leg vertical jump and performance in a 5-hop test were examined. Significant differences of between 4.2% and 16.0% were evident for all measures except for average force during single-leg vertical jump between the D and ND limbs, thus revealing a significant strength imbalance. The 5-hop test revealed a significant difference between D and ND limbs and showed a moderate correlation with more sophisticated laboratory tests, suggesting a potential use as a field test for the identification of strength imbalance. The results of this study indicate that a significant strength imbalance can exist even in collegiate level athletes, and future research should be conducted to determine how detrimental these imbalances could be in terms of peak performance for athletes, as well as the implications for injury risk.     

Sex and side differences and correlations between quantitative palmar characteristics in a sample Sardinian population

Differences between the sexes and between the sides and the correlations between four quantitative characteristics of palmar dermatoglyphics in a sample population of 809 individuals (418 males and 391 females) from the city of Cagliari, Sardinia, are tested. Males have a greater number of ridges than females, shown by a greater a-b ridge count and A-d ridge count, and a more transverse slope of the main lines, shown by a greater main line index and papillary number. The left palm shows a greater number of ridges than the right palm between the A line and the triradius d and between the triradii a and b, with a lower main line index and papillary number. The a-b ridge count has a negative correlation with the main line index and with the papillary number and a positive one with the A-d ridge count; these correlations are greater in the left palms, especially in the males.     

Cerebral lateralization for motor tasks in simulated microgravity a Transcranial Doppler technique for astronauts

In Space, central cognitive operations are unaffected but humans are slower in perceptual-motor performance. Transcranial Doppler ultrasonography was used to monitor blood flow velocity in both middle cerebral arteries during unilateral and bilateral fingers' movements before, during and after -6 degrees 24 hours of head-down tilt (HDT) in 14 (8 males and 6 females) subjects. Physiologic hemisphere dominance was assessed by breath-holding test. There was a significant main effect of motor task, F(4, 328) = 16.05, p<0.00000001, MSe = 48.2. There was a gender vs head-position interaction F(3,246) = 4.90 p<0.002) MSe = 120. At pre-HDT females were right lateralized and males were left lateralized. A left shift in lateralization pattern was seen during 24hrs-HDT for both genders. There was a significant main effect of breath-holding test and a breath-holding test vs head position vs motor task interaction. HDT alters cerebral lateralization for motor control and this may be responsible for slowing in perceptual-motor performance in Space. TCD monitoring may be required for motor performance tasks in Space.     

Effective tempo of the step test for dynamic balance ability in the elderly

This study aimed to examine the reliability and sex- and age-related differences of step tests with stipulated tempos as well as to clarify useful test parameters and tempos. One hundred forty elderly people and fifty young adults conducted tapping and stepping tests, matching the tempo provided by a metronome. Both tests involve movements where the subject touches a sheet with both the right and left hands or right and left legs at a designated spot. Evaluation parameters were the time difference between the beep sound and the time at which the sheet was touched in both tests as well as two-leg support and one-leg support times in the step test. The trial-to-trial reliability of the parameters in both tests was high. The time differences of both 40 bpm tests in the elderly were larger in males than in females. In the step test, the time difference and two-leg support times of the elderly were larger, in the order of 40, 60, and 120 bpm, and the one-leg support time was less in 40 bpm than 60 bpm or 120 bpm. The one-leg support time of the young subjects was larger, in the order of 40, 60, and 120 bpm. A significant age-related difference was found in the 40 bpm and 60 bpm test, and the time difference and two-leg support time were larger in the elderly while the one-leg support time was larger in the young subjects. The time difference at 40 bpm in the elderly was larger in the step test than in the tap test. There was no significant difference between both tests in the young subjects. In conclusion, the step test with the slow tempo, because it requires a long one-leg support phase, is effective for evaluating dynamic balance in the elderly. The time difference and two-leg and one-leg support times are effective evaluation parameters of the step test.     

Morphology of genital system and reproductive biology of the arctic calanoid copepod Metridia longa

This paper considers features of the external morphology and internal structure of the genital system of adult males and females of Metridia longa Lubbock from the White Sea, as well as related with them features of reproduction biology of this mass Arctic copepod. Males of M. longa are dimorphically asymmetric. In the population, there are two morphotypes, which are mirror images of each other. Asymmetry manifests in them as the presence of a right (males ??righties??) or left (males ??lefties??) geniculate antenna, structure of the fifth pair of swimming legs, and location of an unpaired gonad and genital opening. The relative position of these structures is linked together. In females, there are two widely spaced copulator pores that lead to the two spermathecae not connected to each other. The latter, in turn, are connected to two gonopores, through which shedding of eggs occurs. The vast majority of the females in the studied population M. longa in all seasons of the year had only one filled spermatheca, either the right or the left. The females with bilateral insemination also occurred, but did not exceed 2.7% of all specimens. The ratio of females with the right and left filled spermathecae and ??right-handed?? and ??left-handed?? males suggests that the male morphotype determines in which spermathecae male gonads are most likely to get into. The presence of females with two filled spermathecae implicates insemination by two males of different morphotypes. Since each spermatheca is connected to only one of the two oviducts, it is assumed that a half of the eggs produced by unilateral inseminated females remains not fertilized. The morphology of genital structures and literature data on the egg production of M. longa indicate that almost a half of eggs produced by females is not viable and thus wasted.     

The effect of aging on the backward stepping reaction as estimated from the velocity of center of foot pressure and muscular strength

By estimating the deflection velocity from the center of foot pressure (COP), this study aims to prove that the characteristics of the backward stepping reaction in the elderly are related to the strength of the antigravity muscles. The participants in this study were 10 elderly (average age 75.6+/-7.6 years) and 13 young (average age 22.0+/-2.6 years) subjects. Using force plate analysis, we measured the shift in the deflection velocity (V-RMS) and the maximum deflection velocity (V-MAX) from the beginning of the COP movement to the onset of the stepping reaction. Furthermore, we measured the strength of the antigravity muscles using a hand-held dynamometer. We correlated the V-RMS, V-MAX, and the rate of change of the deflection velocity (MAX/RMS) with muscular strength. When compared with the young subjects, the elderly showed significantly lower values of V-RMS (p<0.05) and significantly higher values of MAX/RMS (p<0.01). Furthermore, when compared with the young subjects, the elderly showed significantly lower values of muscular strength for all muscles studied (p<0.001). We established a significant correlation between the V-RMS, MAX/RMS, and muscular strength by carrying out a regression analysis (V-RMS: gluteus maximus (r=0.50, p<0.05) and rectus abdominis (r=0.48, p<0.05); MAX/RMS: adductor magnus (r=-0.66, p<0.001) and flexor digitorum longus (r=-0.62, p<0.01)). Differences were observed in the V-RMS and MAX/RMS during the backward stepping reaction; it was proposed that these differences were related to the age and muscular strength of the subjects. Therefore, further investigations should be undertaken in order to understand the effects of aging on the stepping reaction. In other words, the change-in-support strategy, including the preparatory phase of the stepping reaction, and its relationship with muscular strength should be further investigated.     

Laterality patterns in infants with external birth defects.

The lateral distribution of external birth defects has not been reported in a comprehensive way, and patterns in this distribution have not been examined. This study presents the lateral distribution of 6,390 unilateral defects from among 102 defect categories in data collected by the Metropolitan Atlanta Congenital Defects Program. Among all defects, 49% (95% CI 48-51%) were right-sided. Among males and females, 51% (95% CI 50-53%) and 47% (95% CI 46-49%) of the defects, respectively, were right-sided. Of the 102 defect types, 57 had an excess of defects on the right side of the body; 39 had an excess of defects on the left side; and 6 were equally distributed. The excess on the right side was statistically significant for inguinal hernia, incarcerated inguinal hernia, microtia, preauricular sinus, talipes calcaneovalgus, and lambdoidal craniosynostosis. For the left side, the excess was statistically significant for preauricular tags, cleft lip, fused lip and cleft gum, cleft lip with cleft palate, congenital hip dysplasia, unstable hip, absent forearm or hand, anomaly of the knee, and skin tags. The percentage of right-sided defects among case subjects with unilateral defects was correlated with the percentage of males among all case subjects (r = 0.24, P < 0.05). Among male case subjects with unilateral defects, the correlation coefficient was 0.31 (P < 0. 01), and among females with unilateral defects, it was 0.11 (P > 0. 10). Differences in the lateral distribution of specific birth defects may be due to subtle differences in morphogenesis on the left and right sides of the embryo brought about by establishment of left-right asymmetry prior to organogenesis. The fact that more defect categories were right-sided than left-sided may be related to the observation that mitochondrial maturation in rat embryos is delayed on the right side. The right side, therefore, may be more susceptible than the left to defects caused by prenatal hypoxia. The significant correlation between the percentage right-sided and percentage male may then also be related to the observation that male sex hormones lower the mitochondrial respiration rate in rats and increase rat sensitivity to chemical hypoxia. Investigators should consider reporting the laterality of specific defects in both laboratory and epidemiological studies of birth defects. Right- and left-sided defects should perhaps be considered separately in etiologic studies of birth defects. Teratology 60:265-271, 1999. Published 1999 Wiley-Liss, Inc.     

Age and sex influences on urine calcitonin-like immunoreactivity in normal subjects

Calcitonin-like immunoreactivity levels were determined in urine specimens in 585 normal subjects of various ages. Urine calcitonin-like immunoreactivity (uCTi) was measured by the midportion-specific radioimmunoassay after extraction of urine by gel chromatography on a 0.8 X 20 cm column of Bio Gel P-2. In 197 males and 169 females below 20 years old, significant negative correlations between the age and uCTi were observed (male: r = -0.684, female: r = -0.690). In 75 males and 80 females above 41 years, however, no significant correlation was observed between age and uCTi. The high level of uCTi in children could be explained by high levels of circulating calcitonin, associated with rapid bone growth; however the uCTi level in the elderly may not reflect the physiological significance of calcitonin for them because of a suspected age-related decrease in renal clearance of uCTi in the elderly.     

Validity and reliability of a new stair sprinting test of explosive power

The purpose of this study was to examine the validity and reliability of a new stair sprinting power (SSP) test and, in addition, develop norms for college-age students. Two hundred twenty-seven college-age volunteers participated in the study (ages: males, [Latin capital letter X with macron above] = 21.6 +/- 2.264 years; females, [Latin capital letter X with macron above] = 22.3 +/- 4.214 years). The majority (n = 192) were tested with stopwatches, and 35 were tested using Speedtrap II. Participants began with their back to a wall 1.87 m from the first step of a 2.04-m high staircase of which they sprinted 2 steps per stride to the top. Scores were explosive power = (body mass (kg) x 98 x 2.04)/time (s). Excellent test-retest reliability (intraclass R) was demonstrated: overall, F(1, 226) = 0.420, p = 0.518, R = 0.986; stopwatch: males, F(1, 118) = 0.045, p = 0.833, R = 0.970; and females, F(1, 72) = 0.000, p = 0.998, R = 0.977; and the Speedtrap II: males, F(1, 15) = 2.599, p = 0.128, R = 0.982; and females, F(1, 18) = 0.010, p = 0.921, R = 0.980. In addition, vertical jumping distance (VJD) was acquired on 25 of the Speedtrap II participants. Using Pearson product moment correlation, relationships were determined between SSP, vertical jumping distance (VJD), and vertical jumping power (VJP): VJP = (W) = 51.9 x countermovement VJD (cm) + 48.9 x body mass (kg) - 2007. Overall, the correlation between SSP and VJD was strong, r = 0.692, p = 0.000; however, correlations by sex were neither significant nor meaningful. Significantly strong correlations were found between SSP and VJP: overall, r = 0.943, p = 0.000; males, r = 0.903, p = 0.000; and females, r = 0.835, p = 0.000. It was concluded that the new test was safe, quick, easy to administer, inexpensive, reliable, and valid both logically and concurrently when used with college-age males and females.     

Incidence of hydronephrosis among several production colonies of outbred Sprague-Dawley rats

The incidence of hydronephrosis was determined in nine production colonies of Crl:CD (SD) BR rats (CD rats). Kidneys from 3909 rats were examined and 79 (2.0%) had unilateral or bilateral hydronephrosis. A colony with a relatively high incidence of hydronephrosis (4.1%) was chosen for further study. In unselected rats from this colony the incidence in females (87/1882, 4.6%) was not significantly different from that in males (79/1862, 4.2%). In the same group of rats, hydronephrosis was observed most frequently in the right kidney only (2.3%), followed by bilateral involvement (1.2%) and the left kidney only (0.8%). By selection and inbreeding, the incidence of hydronephrosis was increased dramatically (to 33.6%) in two generations. Hydronephrosis in the CD rat appears to be a highly heritable trait, most likely involving more than one gene.     

A preliminary investigation into the relationship between functional movement screen scores and athletic physical performance in female team sport athletes

There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearman''s correlations (p ≤ 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p ≤ 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes.     

The Incidence of Double Hypoglossal Canal in Japanese: Evaluation with Multislice Computed Tomography

ResultsDouble hypoglossal canal was identified in 16.9% of the patients, and was bilateral in 2.2%. Double hypoglossal canal was significantly more frequent on the left side than right (P = 0.004, odds ratio = 1.79) and in males than females (P = 0.011, odds ratio = 1.67). A larger left or right-sided canal was found in 31.6% and 12.2% of the patients, respectively, following the same side preference as that of double hypoglossal canal. Almost perfect agreement was achieved between the two readers (k = 0.975).ConclusionsIn this Japanese population, the prevalence of a double hypoglossal canal was 16.9%, of which 2.2% were bilateral. Double hypoglossal canal was more frequent in males than females, and on the left side than right.     

Sensory lateralization in pain subjective perception for noxious heat stimulus

The aim of the present study was to identify and characterize hemispheric lateralization for pain intensity perception. A sample of 351 healthy volunteers was tested by the immersion of the right hand for 10 s followed by the same test for the left hand (RL group; n = 199) or in a random sequence (RND group; n = 152) into a water bath (48 degrees C, 15 s). Pain intensity was self-reported by the Visual Analogue Scale (VAS). The motor hemispherical Lateralization Index (LI) was obtained by the Edinburgh Inventory. Gender, hand skin fold, interstimulus time and menstrual cycle data in case of female subjects were recorded. The sample, 60.7% females and 39.3% males, 20.4 +/- 0.18 (mean +/- SEM) years old, showed 92.1% right-handed subjects. Left hand VAS was significantly higher than right hand VAS for RL (7.24 +/- 1.31 vs 6.74 +/- 1.52; p < 0.01) and RND (7.24 +/- 0.82 vs 6.73 +/- 1.25; p < 0.01) both for right- and left-handed subjects. A low but significant correlation for VAS scores and LI was found (r = 0.14; p < 0.05 or r = 0.18; p < 0.05, for left or right hand, respectively). Skin fold was statistically similar in both hands (p > 0.05) being highly correlated with each other (r = 0.68; p < 0.05). Pain subjective perception was not correlated to interstimulus time (r = -0.01; p > 0.05). Females showed significantly higher values than males for both left and right hand VAS scores. Periovulatory phase VAS value was significantly higher than luteal phase VAS only for the right hand test (7.57 +/- 0.20 vs 6.47 +/- 0.33; p < 0.01). The results of the present study suggest a lateralization of pain intensity perception to the right hemisphere not correlated with the motor hemispheric lateralization.     

Diaphragmatic relaxation rate after voluntary contractions and uni- and bilateral phrenic stimulation

We compared the rate of relaxation of the diaphragm (RRdi) after unilateral phrenic nerve stimulation, bilateral phrenic nerve stimulations, and short sharp voluntary contractions (sniffs). RRdi was measured as the maximum rate of decline in transdiaphragmatic pressure (Pdi) corrected for the change in Pdi [maximum relaxation rate (MRR)/delta Pdi], the time constant (tau) of the later exponential decline in Pdi, and the time to half relaxation (1/2 RT). In five subjects there was no difference in mean RRdi apart from a smaller MRR/delta Pdi (P less than 0.05) for left unilateral compared with either right unilateral or bilateral needle stimulation. However, RRdi varied unpredictably between unilateral and bilateral stimulation of the phrenic nerve in individual subjects. In the same five subjects, sniffs were found to have a slower RRdi than bilateral stimulations (MRR/delta Pdi 0.0064 +/- 0.0007 vs. 0.0074 +/- 0.0018/ms, tau 57.2 +/- 8.7 vs. 48.2 +/- 7.4 ms, 1/2 RT 108.9 +/- 10.9 vs. 73.9 +/- 6.0 ms; all P less than 0.05). The application and inflation of an abdominal binder to an external pressure of 60 mmHg resulted in a decrease in functional residual capacity (-710 +/- 70 ml), but there was no effect on relaxation parameters. Our findings suggest that in the evaluation of RRdi 1) unilateral hemidiaphragmatic stimulations may not accurately reflect the in vivo contractile properties of the diaphragm, 2) sniff maneuvers are not voluntary equivalents of phrenic nerve stimulations, and 3) RRdi is not affected by abdominal binder inflation up to 60 mmHg.     

Hydronephrosis in the inbred mouse strain DDD

The inbred mouse strain DDD was found to have an extremely high incidence of hydronephrosis (37/37 in adult males and 12/32 in adult females). The hydronephrosis was classified as open with no definite cause for obstruction. The condition was either unilateral in the right kidney or bilateral. Another feature of the hydronephrotic kidney was circulatory failure. Hydronephrosis in strain DDD mice is considered to be a useful experimental animal model with additional possible use, in investigating disturbances of renal haemodynamics and function.