An introduction of various spectroscopic methods to identify in vivo metal wear in total knee arthroplasty.

While the industrial community already employs multiple surface analytical techniques to study compositional wearing of various metallic and nonmetallic materials, as yet, these methods have not been widely introduced into the biological community. We report on a novel approach, using the industrial spectroscopic techniques of X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy equipped with energy dispersive spectroscopy, to identify the fine wear particulates and other impurities deposited within the knee-joint following total knee arthroplasty. In this study, synovial fluid was extracted from knee-joints scheduled for revision of total knee arthroplasty. The small debris flake formed by centrifugation of the fluid was analyzed using the spectroscopic techniques mentioned above. These nondestructive techniques were successful in identifying numerous micron and submicron sized metallic particulates that appear to emanate from both the prosthetic bearing (articulating) surfaces and from backside (nonarticulating) surfaces, even when gross wearing of the prosthetic device was not detectable by direct visual inspection intraoperatively. Most interesting is that the ratio of the in vivo metallic debris is approximately the same ratio as that of the manufactured alloy, indicating prosthetic wearing as opposed to chemical dissolution. More importantly, using these spectroscopic techniques to probe both the surface and below the surface of the synovial deposits, we identify an inhomogeneous distribution of the wear debris. This indicates the need to use multiple techniques in order to adequately identify the elemental composition of the prosthetic wear material.

Microbial adhesion to zirconium alloys.

We present data and analyses concerning the adhesion of clinically relevant Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa (bacteria) and Candida albicans (yeast) to Zircaloy-2 (Zry-2) and Zircadyne-705 (Zr705) surfaces. These zirconium-based materials are similar to those now being used in total hip and knee replacements. Here we study clinical strains of microbes under shaken and stationary exposure conditions, and their ability to adhere to Zr surfaces having different oxide thicknesses. We use X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), viable counts, endotoxin assays, and statistical analysis methods, and demonstrate a predictive model for microbial adhesion based on XPS data.

Aquatic hyphomycetes in polluted groundwater habitats of central Germany.

Polluted groundwater wells located in a former copper shale mining district (11 sites; Mansfelder Land, Central Germany) and in meadows of the Mulde and Elbe rivers (2 sites) were assessed for occurrence and species richness of aquatic hyphomycetes. Water temperatures at all sites were relatively low and fluctuated less than in surface waters. Oxygen concentrations were always below saturation, whereas sulfate, nitrate, and phosphate levels reached extremely high values in several of the wells. Relatively high levels of Pb, Mn, and Fe were found in some of the wells, but overall few concentrations of individual metals and metalloids exceeded European guidelines for drinking water. Pollen tube growth inhibition, used to assess cytotoxicity of the water, ranged between 4 and 50%. Between 1 and 10 distinct species of aquatic hyphomycetes colonized sterile Alnus glutinosa leaves exposed at the Mansfelder Land sites; for the meadow sites, 8-20 species were found. Heliscus lugdunensis and Anguillospora sp. were the two most widespread species. Fungal colonization occurred much more slowly than in surface water, as demonstrated by scanning electron microscopy and the release of conidia from recovered leaves. The conidial output from exposed alder leaves ranged from 0.2 to 95 conidia mg (-1) dry mass, corresponding to 10% of the values for contaminated surface waters in the same region. Overall, groundwater appears to be a marginal habitat for aquatic hyphomycetes, but may nevertheless play a vital role as long-term reservoir facilitating rapid recolonization following a collapse in fungal communities in surface waters.

Expression of ob gene coding the production of the hormone leptin in hepatocytes of liver with steatosis.

Leptin is a circulating pleiotropic hormone that play an important role in appetite control, fat metabolism, regulation of body weight, fetus growth, growth and aging of adults and hematopoiesis. It is expressed abundantly and specifically in the adipose tissue. A liver cell with developed steatosis represents a cell metabolism similar to metabolism of cells of adipose tissue. Analyses of serum leptin and free leptin receptor in the serum of patients with steatosis showed significant variations from reference limits of normal values. However in liver tissue with verified steatosis detection of mRNA gene for leptin was not proven. Such expression of ob gene for leptin was not found even in the liver tissue without steatosis. With respect to the absence of ob gene expression, the direct effect of ob gene expression on other parameters of leptin metabolism could not be evaluated. The RT-PCR method with verified specificity and satisfying sensitivity was developed. The results obtained from analysis of serum leptin and free leptin receptor in the serum are presented and evaluated. The used methods were verified and reference limits for Czech population were defined in dependence on age and other clinical parameters.

Acid precipitation-related chemical trends in 18 rivers of atlantic Canada - 1983 to 1992.

Using non-parametric techniques, we studied water chemistry changes from 1983 to 1992 in 18 rivers located at the extreme northeastern portion of North America. This period was marked by a decrease in sulfate (SO 4 (-) ) production in eastern Canada from 1982 to 1986, followed by a levelling off from 1986 to 1992. Nitrate (NO 3 (-) ) production and deposition generally increased over this whole period. We used two time windows, 1983 to 1989 and 1983 to 1992, to determine if changes in river acidification variables occurred over the ten year period. We found significant trends of increasing pH and acid neutralization capacity (ANC) concentrations at eight sites using both time windows, while SO 4 (-2) increased at five and seven sites during the same two time periods. Nitrate concentrations showed few consistent trends, while base cations showed increases in the earlier part of the data set and total organic carbon (TOC) showed long-term decreases. There were few significant trends in hydrogen (H(+)), and a slight decrease in SO 4 (-2) exports as opposed to increased concentrations over the same period. We attribute the discrepancy between SO 4 (-2) concentration and export trends to be due to evapotranspiration in the basins, causing a concentration of ions in water. Nitrate and calcium exports showed no trends, while TOC decreased at four or five sites, depending on the time window used. Longer data sets tended to produce more detectable trends. Overall, water chemistry in the region is showing the effects of reduced SO 4 (-) loads and is not yet being affected by the increases in NO 3 (-) deposition.

Cardiovascular responses of cardiac transplant patients to arm and leg exercise.

This investigation compares the cardiovascular responses of normal (n = 10) and cardiac transplant (n = 14) subjects to peak arm and leg exercise. It also tests the hypothesis that the higher heart rate (fc) in normal subjects during light (30 W) submaximal arm versus leg exercise is due to cardiac innervation. In cardiac transplant patients, power output, oxygen consumption (VO2), fc and rate pressure product were 54%, 28%, 7%, and 8% lower during peak arm than leg exercise, respectively. In normal subjects, power output, VO2, fc and rate pressure product were 61%, 33%, 8%, and 11% lower during peak arm than leg exercise, respectively. In cardiac transplant patients there was no significant difference in absolute fc during submaximal arm and leg exercise. In normal subjects, absolute fc during arm and leg exercise was [mean (SD)] 97 (4) beats.min-1 and 92 (4) beats.min-1, respectively (P = 0.07). Plasma noradrenaline was increased more during arm than leg exercise in both cardiac transplant and normal subjects. Maximal leg testing is useful when determining the capacity of cardiac transplant patients to perform arm work. The higher absolute fc reported by other investigators for normal subjects during submaximal arm versus leg exercise may be mediated by cardiac innervation.

Left ventricular response to submaximal exercise in endurance-trained athletes and sedentary adults.

This investigation examines the hypothesis that athletes increase stroke volume with submaximal exercise through an augmentation of left ventricular (LV) end-diastolic volume and a reduction of LV end-systolic volume, whereas sedentary adults only increase stroke volume modestly, because LV end-diastolic volume does not increase. Upright bicycle exercise was performed by 17 endurance-trained male athletes and 15 sedentary men. M-mode echocardiograms were obtained during submaximal exercise at predetermined heart rates. Athletes, at a heart rate of 130 beats/min, increased their stroke volume 67% from 72 +/- 18 ml to 120 +/- 26 ml (p less than 0.001). This resulted from an increase of LV end-diastolic volume from 119 +/- 23 to 152 +/- 28 ml (p less than 0.001) and a reduction in LV end-systolic volume from 46 +/- 14 to 31 +/- 9 ml (p less than 0.001). Sedentary men at the same heart rate increased stroke volume 22% from 63 +/- 15 to 77 +/- 21 ml (p less than 0.05). LV end-diastolic volume did not change (96 +/- 20 vs 97 +/- 28 ml) (p = not significant), but LV end-systolic volume decreased (33 +/- 11 vs 20 +/- 9 ml) (p less than 0.001). In conclusion, athletes increased cardiac output through a more prominent augmentation of stroke volume than sedentary subjects at submaximal exercise. This was accomplished through an augmentation of LV end-diastolic volume. This may have a conserving effect on myocardial oxygen consumption at these levels of exercise.

Cardiovascular responses of heart transplant recipients to graded exercise testing.

A group of orthotopic heart transplant (OHT, n = 28) and heart surgery (n = 19) patients, with similar ejection fractions and left ventricular end-diastolic pressures, were exercised to symptom-limited maximum to describe differences in cardiovascular and gas exchange responses. Testing was performed at a mean of 3 and 6 mo after surgery, respectively (P less than 0.05). OHT patients have a greater resting systolic and diastolic blood pressure (P less than 0.01) and a significantly greater (P less than 0.01) heart rate (HR) at rest in the supine and standing positions and during minutes 2 through 7 of supine recovery. Peak treadmill time was significantly less (P less than 0.01) in OHT patients. No significant differences were found for systolic blood pressure (SBP) during recovery, peak HR, ventilation, relative O2 uptake (VO2), body weight, ventilatory equivalents for O2 and CO2, O2 pulse, and HR-SBP product (peak HR x peak SBP). Peak pulse pressure, heart rate reserve, total VO2, and absolute VO2 at ventilatory threshold were significantly lower (P less than 0.01) in the OHT patients. We concluded that 1) complete cardiac decentralization is evident, 2) the significantly reduced VO2 at ventilatory threshold should be considered when activities of daily living are prescribed, and 3) SBP response is more appropriate than HR for assessing recovery of the decentralized heart after maximal exercise.

Assessment of body composition in heart transplant patients.

Orthotopic heart transplantation (OHT) recipients often experience increased body weight (BW) following surgery. Using hydrostatic weighing (HW), this study assessed the body density (BD) and body composition of 17 white and seven black male OHT patients. It examined the cross-validity of the Jackson and Pollock seven and three site skinfold (SF) regression equations for predicting BD in these patients. We hypothesized that both prednisone (P) dose and months post-operative (MPO) would be inversely related to BD. The average of the last five of ten HW trials was used in computing BD. BW and % body fat (BF) were 88.5 +/- 17.8 kg (mean +/- SD) and 33.5 +/- 9.4%, respectively. The correlation coefficient between hydrostatically determined BD and BD determined via two of the three intercept revised Jackson and Pollock SF equations was r = 0.89, SE = 0.009. A polynomial regression model for BD using P dose and MPO provided a correlation coefficient of r = 0.71, SE = 0.015. Partial correlation techniques incorporating SF, age, MPO, and P dose indicated that neither P dose or MPO provided any significant additive effect, above SF and age, when predicting BD. We conclude that in OHT patients receiving glucocorticoids, the intercept revised Jackson and Pollock SF regression equations are generally applicable and associated with a SE of +/- 4 BF percentage points. Up to 49 months after OHT, both P dose and MPO are inversely related to BD but provide no additive value above SF for predicting BD.

Cardiovascular responses of heart transplant patients to exercise training.

Orthotopic heart transplantation (OHT) represents an effective alternative for individuals with end-stage heart disease. The current literature reports only the responses of OHT patients to greater than or equal to 4 mo of exercise training (ET) and frequently lacks adequate controls. Most programs currently treating OHT patients usually provide 6-12 wk of ET. This study describes the effects of a 10-wk supervised ET program in 12 male OHT patients and 5 other male OHT patients who served as a comparison group. Graded exercise tests were performed before and after ET. After ET, maximal O2 consumption was significantly greater for the ET group than the comparison group (P less than 0.05) and the mean increase in peak heart rate was 18 +/- 4 and 6 +/- 4 (SE) min-1 for ET and comparison groups, respectively (P less than 0.05). Maximal ventilation was also significantly greater for the ET group at after ET, while resting heart rate and blood pressure and peak blood pressure, O2 pulse, respiratory rate, and ventilatory equivalents for O2 and CO2 were not significantly changed. We conclude that after OHT a 10-wk ET program improves maximal O2 consumption and, by improving peak heart rate, improves O2 delivery.

Enzootic Brugia infection in a two-year-old Colombian girl.

Mature male and female filarial worms were present in a lymphatic vessel near a retro-auricular lymph node removed from a 2-year old Colombian girl. Although apparently mature microfilariae were present in the uterus of the female, none was detected in blood samples (Knott's) of peripheral blood taken during day or night. The identification of the worms as a species of Brugia is suggested by their location in a dilated lymphatic vessel, morphology of adults, and the distribution pattern of tail nuclei of the microfilariae. This case is similar to another Colombian case reported from the Departamento del Santander del Sur, and suggests that zoonotic filarial infections may not be uncommon in Colombia.