Reliability of the Etest in light of the correlation between an antibiotic's critical concentration (Cc) and MIC values.

The study relates to the theory of diffusion methods for antibiotic sensitivity testing. The aim of the study was to show the relationship between the antibiotic critical concentration (Cc) and its minimum inhibitory concentration (MIC). The results contribute to the explanation of the Etest's reliability and support the scientific basis for MIC determination using agar diffusion methods. Susceptibility among 90 clinical isolates of 12 common aerobic bacterial species to gentamicin, erythromycin, or oxacillin was assessed using the multidisc method (for Cc), by the agar dilution method (for MIC) and by the Etest. The results of all three methods were statistically compared and found to be closely related. The regression equation for Cc values and MIC was log2(MIC) = 0.99 x log2(Cc)-0.13; r = 0.99; p < 0.05; the regression equation for Cc values and Etest-MIC (Et) was log2(Et) = 0.86 x log2 (Cc)+0.34; r = 0.96; p < 0.05; the regression equation for Etest-MIC values and MIC was log2(MIC) = 1.12 x log2(Et)-0.50; r = 0.96; p < 0.05.     

Reference values of pulmonary diffusing capacity for nitric oxide in an adult population.

Our objective was to create reference values for single-breath DLNO based on a sample of non-smoking healthy males and females using a short breath-hold time. The sample included 130 individuals varied in age (18-85 yr), height (149-190 cm), and weight (49.4-102.6 kg). The subjects performed single-breath-hold maneuvers at rest inhaling 41 +/- 6 ppm NO and a standard diffusion mixture. The breath-hold time was 5.5 +/ -0.6 s. Multiple linear regression with backward elimination of the independent variables age, weight, gender, and either measured lung volume (called alveolar volume or VA) or height revealed specific prediction equations for DLNO. Inserting VA instead of height into the regression equation determined how much of an abnormality of DLNO was due to gas exchange versus low lung volume. The predicted DLNO adjusted for lung volume (ml/min/mmHg) = DLNO = 73.1 + 17.26 x (VA)+17.56 x (gender) - 1.0 x (age). The predicted DLNO unadjusted for lung volume (ml/min/mmHg) = -20.1 + 1.167 x (height)+31.81 x (gender) - 1.21 x (age). For gender, 1 = males, 0 = females; VA = liters; height = cm. Age, gender and VA (lung volume) were the best predictors of DLNO and DLCO. Weight was not a good independent predictor of DLNO or DLCO. When normalizing for height and age, women have 650 ml lower forced vital capacity, 660 ml lower VA, and a 6 and 32 ml/min/mmHg lower DLCO and DLNO, respectively, compared to men. Normalizing for lung volume and age, women have, on average, a 3.2 and 18 ml/min/mmHg lower DLCO and DLNO, respectively, compared to men.     

Aerosol-derived lung morphometry: comparisons with a lung model and lung function indexes.

This study evaluated the ability of aerosol-derived lung morphometry to noninvasively probe airway and acinar dimensions. Effective air-space diameters (EAD) were calculated from the time-dependent gravitational losses of 1-microns particles from inhaled aerosol boluses during breath holding. In 17 males [33 +/- 7 (SD) yr] the relationship between EAD and volumetric penetration of the bolus into the lungs (Vp) could be expressed by the linear power-law function, log (EAD) alpha beta log (Vp). Our EAD values were consistent with Weibel's symmetric lung model A for small airways and more distal air spaces. As lung volume increased from 57 to 87% of total lung capacity (TLC), EAD at Vp of 160 and 550 cm3 increased 70 and 41%, respectively. At 57% TLC, log (EAD) at 160 cm3 was significantly correlated with airway resistance (r = -0.57, P less than 0.0204) but not with forced expired flow between 25 and 75% of vital capacity. Log (EAD) at 400 cm3 was correlated with deposition of 1-micron particles (r = -0.73, P less than 0.0009). We conclude that aerosol-derived lung morphometry is a responsive noninvasive probe of peripheral air-space diameters.     

Estimation of skeletal muscle mass by bioelectrical impedance analysis.

The purpose of this study was to develop and cross-validate predictive equations for estimating skeletal muscle (SM) mass using bioelectrical impedance analysis (BIA). Whole body SM mass, determined by magnetic resonance imaging, was compared with BIA measurements in a multiethnic sample of 388 men and women, aged 18-86 yr, at two different laboratories. Within each laboratory, equations for predicting SM mass from BIA measurements were derived using the data of the Caucasian subjects. These equations were then applied to the Caucasian subjects from the other laboratory to cross-validate the BIA method. Because the equations cross-validated (i.e., were not different), the data from both laboratories were pooled to generate the final regression equation SM mass (kg) = [(Ht²/ R x 0.401) + (gender x 3.825) + (age x -0. 071)] + 5.102 where Ht is height in centimeters; R is BIA resistance in ohms; for gender, men = 1 and women = 0; and age is in years. The r(2) and SE of estimate of the regression equation were 0.86 and 2.7 kg (9%), respectively. The Caucasian-derived equation was applicable to Hispanics and African-Americans, but it underestimated SM mass in Asians. These results suggest that the BIA equation provides valid estimates of SM mass in healthy adults varying in age and adiposity.     

Equation for estimating total body water by bioelectrical impedance measurements in Japanese subjects]

This article reports a study in which the equation for total body water (TBW) estimated from deuterium (2H2O)-dilution method and bioelectrical impedance measurement (BIM) is described. Subjects were 60 healthy males aged 30 +/- 18.3 yr (18-74) and 31 healthy females aged 37 +/- 17.5 yr (19-70). Total body water determined by the analysis of the dilution of orally ingested deuterium oxide (1g2H2O, 99.75 atom % excess/kg body weight) in urine. Bioelectrical impedance was measured for each subjects in a supine position using an electrical impedance analyzer (500 microA, 50kHz, T-1988K, Toyo Physical Inc.) with a four electrodes (Y-250, Nihon Kohden). The mean values of total body water and the impedance in males and females subjects were 34.1 +/- 4.27 l and 25.7 +/- 2.42 l, 567 +/- 28.5 omega and 562 +/- 32.5 omega, respectively. Height squared divided by resistance (Ht2/R) correlated well with TBW as measured by 2H2 O, r = 0.530 (p less than 0.001) in males and r = 0.782 (p less than 0.001) in females. The best-fitting regression equation to predict TBW comprised Ht2/R(X1) and body weight (X2) (R = 0.915, SEE = 1.70 l in males and R = 0.834, SEE = 1.28 l in females). Equations were provided with BIM instrument for the prediction of TBW: for males TBW, l = 0.1983X1 + 0.4004X2 - 0.7938 and for females TBW, l = 0.3536X1 + 0.1269X2 + 3.3417. These results suggest that bioelectrical impedance measurement is a useful measure of total body water in Japanese subjects.     

ESTIMATION OF MICROBIOLOGICAL QUALITY OF CHILLED BEEF USING AUTOMATED TURBIDIMETRY

Total bacterial counts on chilled beef samples were estimated by the standard plate count method and by an automated turbidimetric system. The latter method is based on product-specific calibration curves constructed by correlating growth curve parameters calculated for the turbidimeter to the log CFU values obtained by plate counts. A total of 74 beef samples was used to construct the calibration curves. Correlation analysis between turbidimetric parameters and plate count values showed that detection time was the best predictor to estimate microbial loads on fresh (r=0.91) and aged beef (r=0.94). Microbial loads for a different set of aged beef samples (n = 37) refrigerated for 7, 9, 10, 17 and 45 days were compared by turbidimetric measurements and plate counts. Mean total viable counts were log 5.92 ± 1.17 and log 5.54 ± 1.28 CFU/mL, respectively. Results showed that total bacterial counts on chilled beef could be estimated accurately from turbidimetric parameters. Furthermore, setting a cut-off value of log 6 CFU/mL allowed to accepting/rejecting samples according to their microbial condition in shorter periods of time compared to the traditional plate count method.     

Validation of tetrapolar bioelectrical impedance method to assess human body composition

This study was conducted to validate the relationship between bioelectrical conductance (ht2/R) and densitometrically determined fat-free mass, and to compare the prediction errors of body fatness derived from the tetrapolar impedance method and skinfold thicknesses, relative to hydrodensitometry. One-hundred and fourteen male and female subjects, aged 18-50 yr, with a wide range of fat-free mass (34-96 kg) and percent body fat (4-41%), participated. For males, densitometrically determined fat-free mass was correlated highly (r = 0.979), with fat-free mass predicted from tetrapolar conductance measures using an equation developed for males in a previous study. For females, the correlation between measured fat-free mass and values predicted from the combined (previous and present male data) equation for men also was strong (r = 0.954). The regression coefficients in the male and female regression equations were not significantly different. Relative to hydrodensitometry, the impedance method had a lower predictive error or standard error of the estimates of estimating body fatness than did a standard anthropometric technique (2.7 vs. 3.9%). Therefore this study establishes the validity and reliability of the tetrapolar impedance method for use in assessment of body composition in healthy humans.     

Pulmonary function in young and older athletes and untrained men

This study compared the lung volumes and pulmonary functions of older endurance-trained athletes with those of healthy sedentary age-matched controls, young athletes, and young untrained men to determine whether training affects the age-associated changes in these variables. Despite large differences in maximal 02 consumption (VO2max), the older athletes and their sedentary peers had similar values for all pulmonary variables when expressed as absolute values. However, because the older athletes were shorter than the older sedentary men, their vital capacity, total lung capacity (TLC), and forced expiratory volume in 1 s were significantly larger than those of the older sedentary men when normalized for age and height; the average values for maximal voluntary ventilation and residual volume (RV) were also larger in the older athletes when normalized for age and height, but the differences were not significant. The young trained and untrained men did not differ in any of these measures. TLC was the only pulmonary variable that was the same in the young and older men; RV and the RV-to-TLC ratio were larger, whereas all other pulmonary function and volume measures were lower in the older men compared with the younger men. The older athletes were the only group whose lung volumes and pulmonary function measures were all, except for RV, substantially greater than expected based on their age and height. Thus prolonged strenuous endurance training in these older highly trained endurance athletes appears to have altered the decline in pulmonary function and volumes associated with aging.     

Correlation of total organic carbon and dry weight data as indices of fresh-water zooplankton biomass

Preserved zooplankters from DeGray Lake, Arkansas, U.S.A., were separated from other net seston by density-gradient centrifugation, washed, dried, and weighed. Total organic carbon (TOC) content of zooplankters was determined from carbon analysis involving wet persulfate oxidation. Dry weight and TOC data were highly correlated (r² = 0.9649; P < 0.001) when subjected to a step-wise procedure of the Statistical Analysis System (SAS). The model is represented by the equation log Y =1.14 log X + 0.46, where X = TOC and Y = dry weight. Carbon averaged 30.33 ± 9.86 (S.D.)% of dry weight.     

Proposed standard mass equations for European chub Leuciscus cephalus in Italy

Total length (L(T)) and mass measurements of 28,596 specimens of European chub Leuciscus cephalus, collected from a variety of waterways across Italy, were used to compute standard mass (W(s)) equations by both empirical percentile (EmP) and regression line percentile (RLP) methods. The use of the EmP W(s) equation [log(10) W(s) = -4·79 + 2·68log(10) L(T) + 0·10(log(10) L(T))(2)] to compute relative mass (W(r)) of L. cephalus in Italy is suggested, as it was not influenced by length-related bias (L(T) range of application = 70-470 mm).     

Estimation of oxygen-diffusing capacity in the gills of different sizes of a tilapia, Oreochromis niloticus

Measurements on gills of features that affect gas exchange have been studied in relation to body weight in specimens (0.0112–812.3 g) of a tilapia, Oreochromis niloticus . The data were analysed with respect to body weight by means of logarithmic transformations (log Y = log a+b log W ). The slopes ( b ) of the log/log regression lines for the gill area, harmonic mean diffusion distance and oxygen diffusing capacity were 0.777, 0.077 and 0.700, respectively. The gill respiratory area of O. niloticus (Trewavas) increases as the fish develops because the number and bilateral area of secondary lamellae increase. The scaling value for oxygen-diffusing capacity is less than the value for gill area because of the slight increase in harmonic mean diffusion distance with development.     

Predicting running velocity at blood lactate threshold from running performance tests in adolescent boys

The purpose of this study was to investigate the relationship between running velocity at blood lactate threshold (VLT) and running performance (50 m, 40 s and 5 min) in boys aged 14 years at puberty (n = 30) and young men aged 16-20 years (n = 39), and to examine the possibility of predicting VLT from running performances in boys during adolescence. Special attention was also paid as to whether these parameters are related to bone maturity in boys at puberty. After allowing for chronological age, height, weight and fat content, all the running performances were positively correlated to bone maturity in non-active boys at puberty. In contrast, VLT was negatively correlated to bone maturity. In spite of these results, VLT was significantly related to performance in the 5 min run in both the boys and the young men. However, the correlation coefficient for the former was significantly lower than that for the latter. The 5 min and 40 s runs were selected by stepwise regression analysis for predicting VLT in the two groups. The same predictor was selected from the combined data from both groups using the following equation: VLT(m X min-1) = 124 - 0.83 X 40 s run(m) + 0.202 X 5 min run(m). The correlation between actual and estimated VLT, and the standard error of the estimate of this formula were 0.726 and - 5 + 15 m X min-1 in the boys, and 0.880 and 4 + 11 m X min-1 in the young men, respectively. This formula was similar in precision to the formulae obtained from the data in each individual group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Allometric scaling of isokinetic peak torque: the Nebraska Wrestling Study

Allometric scaling has been used increasingly in the exercise sciences to control statistically for body size differences in physical performance variables. The purpose of this study was to use multivariate allometric scaling to examine the influence of fat-free mass (FFM) on age-related differences in strength in young club (8-13 years) and high-school (14-18 years) wrestlers. The dependent variables were log-transformed values of isokinetic peak torque for leg extension and flexion at 0.52, 3.14, and 5.24 rad x s(-1)(30, 180, and 300 x s(-1)). The independent variables used in the multiple regression analyses were log-transformed values for FFM, age, and the FFM versus age interaction. The resulting regression equations were of the form: log Y = log a + b1 log X1 + b2 log X2 + bn log Xn. The initial multiple regression analyses showed significant interaction effects (P < 0.05) for all dependent variables, therefore separate regression analyses were performed for the younger and older groups of wrestlers. The results indicate that for the younger wrestlers there were increases in isokinetic peak torque at all velocities across age after controlling for FFM. The FFM scaling exponents ranged from 0.94 to 1.31. All exponents included 1.0 in the 95% confidence interval, except for extension at 3.14 rad x s(-1). For the high-school wrestlers, both FFM and age were significant for the extension data, but only FFM was significant for the flexion data. All FFM exponents included 1.0 in the 95% confidence interval. These results indicate that the relationship between FFM and peak torque differed across age. In addition, with the exception of the flexion data for the high-school wrestlers, within each group increases in isokinetic peak torque occurred across age, independent of increases in FFM. The causes of the age effect for strength are speculative, but it may be due to developmental changes in neuromuscular function, alterations in the distribution of muscle mass as a percentage of FFM and/or the distribution of FFM across body segments.     

Weight-height relationships and body mass index: some observations from the Diverse Populations Collaboration

Body mass index (BMI, weight (kg)/height (m)(2)) is the most widely used weight-height index worldwide. This universal use of BMI assumes that the rationale for its use is universally applicable. We examine two possible rationales for using BMI as a universal measure. The first rationale is that BMI is strongly correlated with weight, but is independent of height. The second rationale is that BMI correctly captures the relationship between weight and height, which implies that the slope of log weight regressed on log height is 2. We examined the weight-height relationship in 25 diverse population samples of men and women from the US, Europe, and Asia. The analysis included 72 subgroups with a total of 385,232 adults aged 25 years and older. Although BMI was highly correlated with weight in all studies, a significant, negative correlation between BMI and height was found in 31 out of 40 subgroups of men (r=-0.004 to -0.133) and 32 of 32 groups of women (r=-0.016 to -0.205). When log weight was regressed on log height, the 95% confidence intervals (CI) of the slopes did not include 2 in 25 out of 40 male subgroups. The summary estimate of the slopes across studies of men was 1.92 (95% CI, 1.87-1.97). For women, slopes were lower than 2 in 28 of 32 subgroups with a summary estimate of 1.45 (95% CI, 1.39-1.51). In most of the populations, BMI is not independent of height; weight does not universally vary with the square of height; and the relationship between weight and height differs significantly between males and females. The use of a single BMI standard for both men and women cannot be justified on the basis of weight-height relationships.     

Attenuation of skeletal muscle and strength in the elderly: The Health ABC Study.

Although loss of muscle mass is considered a cause of diminished muscle strength with aging, little is known regarding whether composition of aging muscle affects strength. The skeletal muscle attenuation coefficient, as determined by computed tomography, is a noninvasive measure of muscle density, and lower values reflect increased muscle lipid content. This investigation examined the hypothesis that lower values for muscle attenuation are associated with lower voluntary isokinetic knee extensor strength at 60 degrees/s in 2,627 men and women aged 70-79 yr participating in baseline studies of the Health ABC Study, a longitudinal study of health, aging, and body composition. Strength was higher in men than in women (132.3 +/- 34.5 vs. 81.4 +/- 22.0 N x m, P < 0.01). Men had greater muscle attenuation values (37.3 +/- 6.5 vs. 34.7 +/- 7.0 Hounsfield units) and muscle cross-sectional area (CSA) at the midthigh than women (132.7 +/- 22.4 vs. 93.3 +/- 17.5 cm(2), P < 0.01 for both). The strength per muscle CSA (specific force) was also higher in men (1.00 +/- 0.21 vs. 0.88 +/- 0.21 N x m x cm(-2)). The attenuation coefficient was significantly lower for hamstrings than for quadriceps (28.7 +/- 8.7 vs. 41.1 +/- 6.9 Hounsfield units, P < 0.01). Midthigh muscle attenuation values were lowest (P < 0.01) in the eldest men and women and were negatively associated with total body fat (r = -0.53, P < 0.01). Higher muscle attenuation values were also associated with greater specific force production (r = 0.26, P < 0.01). Multivariate regression analysis revealed that the attenuation coefficient of muscle was independently associated with muscle strength after adjustment for muscle CSA and midthigh adipose tissue in men and women. These results demonstrate that the attenuation values of muscle on computed tomography in older persons can account for differences in muscle strength not attributed to muscle quantity.     

男性新生儿血红蛋白正常参考值与中国地理因素

目的:为制定中国男性新生儿血红蛋白正常参考值的统一标准提供科学依据。方法:收集了中国78个单位用氰化高铁血红蛋白(HiCN)法测定的5169例男性新生儿血红蛋白正常参考值,运用相关分析和回归分析的方法,研究了其与地理因素的关系。结果:发现男性新生儿血红蛋白正常参考值与中国地理因素之间有很显著的相关关系(F=17.93)。用逐步回归分析的方法推导出了一个回归方程:Y=156.8+0.01670X1+0.4140X3-0.008596X5±25.1。结论:如果知道了中国某地的地理因素,就可以用回归方程估算这个地区的血红蛋白正常参考值。依据血红蛋白正常参考值与地理因素的依赖关系把中国分为青藏区、西南区、西北区、东南区、华北区、东北区等六个区。     

The numbers of landbird species on the Isles of scilly

A multiple regression analysis was performed to establish relationships between the number of breeding landbird species and selected environmental variables for the Isles of Scilly, England.
Two analyses were made: the first with all variables log converted, the second without log conversion. In the log model the number of landbird species ( S ) was correlated with island area, r ²= 85.98. In the non-log model, S was most highly correlated with the number of habitats on an island.
Partial correlation analyses confirmed the importance of habitats, rejecting the importance of island area, and indicating that increasing intra-archipelagal isolation alone does not reduce the number of breeding species.     

Changes of the uterine size during pregnancy in cynomolgus monkeys (Macaca fascicularis) (author's transl)]

This paper describes changes in the uterine size during the normal course of pregnancy in cynomolgus monkeys. Twenty-four females which had conceived by 3-day individual mating with a male were laparotomized 4,5,6,7,8,9,10,15 and 20 weeks after conception. The width, thickness and length of uterus were measured by a pair of callipers. Them, the uterine volume was estimated by the formula, V = 4/3 piab2 (a, b: uterine length x 1/2, uterine width x 1/2). The increase in the uterine width (y) during pregnancy could be expressed as a linear equation: y = 0.35x + 1.48 (x: weeks after conception). The thickness of pregnant uteri could be represented by a a linear equation: y = 0.36x + 1.40. From the 4th to the 20th week of pregnancy, the uterine length increased along a straight line expressed as a linear equation: y = 0.58x + 1.14. Except for nonpregnant uteri, the change in the uterine volume after pregnancy could be expressed as a linear logarithmic equation: log y = 2.319 log x -0.315. These 24 pregnant monkeys had followed the normal course of gestation until the time of laparotomy without any abnormality in their fetuses of their placentas, indicating that the values obtained throughout this study are of practical use for taking care of pregnant cynomolgus monkeys.     

Comparison of agar plate and real-time PCR on enumeration of Lactobacillus, Clostridium perfringens and total anaerobic bacteria in dog faeces

AIMS: To compare agar plate and real-time PCR methods on enumeration of total anaerobic bacteria, Lactobacillus and Clostridium perfringens in dog faeces. METHODS AND RESULTS: Thirty-two faecal specimens from Labrador retriever dogs were used to compare agar plate and real-time PCR enumeration methods for Lactobacillus, C. perfringens and total anaerobic bacteria. Total anaerobic bacteria, C. perfringens and Lactobacillus of faeces were counted (as CFU g(-1) faeces) for 48-h incubation at 37 degrees C in an anaerobic gas chamber on genus-selective media. Total genomic DNA from samples was extracted by the QIAamp DNA stool mini kit. The quantification of DNA (as DNA copy per gram faeces) by real-time PCR was performed with a LightCycler system with the QuantiTect SYBR green PCR kit for PCR amplification. The results indicated that there was a significant correlation between CFU and DNA copy of Lactobacillus (R2 = 0.78, P < 0.01) and total anaerobic bacteria (R2 = 0.21, P < 0.05); but no correlation was found between CFU and DNA copy of C. perfringens. The regression equations for Lactobacillus and total anaerobic bacteria were log(DNA copy) = 0.83 x log(CFU) + 1.43 and log(DNA copy) = 1.62 x log(CFU) - 6.32 respectively. CONCLUSIONS: The real-time PCR method could be used to enumerate Lactobacillus within 2 days when compared with plating method which requires 5-6 days. SIGNIFICANCE AND IMPACT OF THE STUDY: The real-time PCR method and the primer set for Lactobacillus spp. harboured in the dog intestine can be used for rapid enumeration of lactobacilli and monitoring of the faecal Lactobacillus community.     

广西英罗湾红海榄群落凋落物研究

本文主要研究广西合浦山口英罗湾红树林保护区红海榄群落的凋落物,结果表明:(1)红海榄群落1989年凋落物量为631.26 g/m~2,其中落叶561.50 g/m~2,说明落叶在红海榄群落物质归还中起着关键性作用。(2)年凋落物中各组分占总量的比例分别为叶88.95％、花3.68％、果(含胚轴)3.0％和枝4.26％。(3)月凋落物量(Y_1,g/m~2)与月平均气温(X_1,℃)呈线性正相关,其回归公式为Y_1=3.071 x_1-16.804(r=0.77,df=14),相关极显著;月凋落物量(Y_1)与月降水量(X_2,mm)的回归公式为Y_1=0.116 x_2+34.381(r=0.62,df=14),相关极显著。高温高湿季节的凋落物量明显高于低温干燥季节的凋落物量。