Evidence for an additional effect of whole-body vibration above resistive exercise alone in preventing bone loss during prolonged bed rest.

SUMMARY: The addition of whole-body vibration to high-load resistive exercise may provide a better stimulus for the reduction of bone loss during prolonged bed rest (spaceflight simulation) than high-load resistive exercise alone. INTRODUCTION: Prior work suggests that the addition of whole-body vibration to high-load resistive exercise (RVE) may be more effective in preventing bone loss in spaceflight and its simulation (bed rest) than resistive exercise alone (RE), though this hypothesis has not been tested in humans. METHODS: Twenty-four male subjects as part of the 2nd Berlin Bed Rest Study performed RVE (n = 7), RE (n = 8) or no exercise (control, n = 9) during 60-day head-down tilt bed rest. Whole-body, spine and total hip dual X-ray absorptiometry (DXA) measurements as well as peripheral quantitative computed tomography measurements of the tibia were conducted during bed rest and up to 90 days afterwards. RESULTS: A better retention of bone mass in RVE than RE was seen at the tibial diaphysis and proximal femur (p ≤ 0.024). Compared to control, RVE retained bone mass at the distal tibia and DXA leg sub-region (p ≤ 0.020), but with no significant difference to RE (p ≥ 0.10). RE impacted significantly (p = 0.038) on DXA leg sub-region bone mass only. Calf muscle size was impacted similarly by both RVE and RE. On lumbar spine DXA, whole-body DXA and calcium excretion measures, few differences between the groups were observed. CONCLUSIONS: Whilst further countermeasure optimisation is required, the results provide evidence that (1) combining whole-body vibration and high-load resistance exercise may be more efficient than high-load resistive exercise alone in preventing bone loss at some skeletal sites during and after prolonged bed rest and (2) the effects of exercise during bed rest impact upon bone recovery up to 3 months afterwards.

In vitro investigation of titanium and hydroxyapatite dental implant surfaces using a rat bone marrow stromal cell culture system.

In this study, rat bone marrow cells (RBM) were used to evaluate different titanium and hydroxyapatite dental implant surfaces. The implant surfaces investigated were: a titanium surface having a porous titanium plasma-sprayed coating (sample code Ti-TPS), a titanium surface with a deep profile structure (sample code Ti-DPS), an uncoated titanium substrate with a machined surface (sample code Ti-ma) and a machined titanium substrate with a porous hydroxyapatite plasma-sprayed coating (sample code Ti-HA). RBM cells were cultured on the disc-shaped test substrates for 14 days. The culture medium was changed daily and examined for calcium and phosphate concentrations. After 14 days specimens were examined by light microscopy, scanning electron microscopy, energy dispersive X-ray analysis and morphometry of the cell-covered substrate surface. All test substrates facilitated RBM growth of extracellular matrix formation. Ti-DPS and Ti-TPS to the highest degree, followed by Ti-ma and Ti-HA. Ti-DPS and Ti-TPS displayed the highest cell density and thus seem to be well suited for the endosseous portion of dental implants. RBM cells cultured on Ti-HA showed a delayed growth pattern. This may be related to its high phosphate ion release.

Evaluation of calcium phosphates and experimental calcium phosphate bone cements using osteogenic cultures.

In this study, rat bone marrow cells (RBM) were used to evaluate two biodegradable calcium phosphate bone cements and bioactive calcium phosphate ceramics. The substances investigated were: two novel calcium phosphate cements, Biocement F and Biocement H, tricalcium phosphate (TCP), surface-modified alpha-tricalcium phosphate [TCP (s)] and a rapid resorbable calcium phosphate ceramic consisting of CaKPO(4) (sample code R5). RBM cells were cultured on disc-shaped test substrates for 14 days. The culture medium was changed daily and also examined for calcium, phosphate, and potassium concentrations. Specimens were evaluated using light microscopy, and morphometry of the cell-covered substrate surface, scanning electron microscopy, and energy dispersive X-ray analysis and morphometry of the cell-covered substrate surface. Areas of mineralization were identified by tetracyline labeling. Except for R 5, rat bone-marrow cells attached and grew on all substrate surfaces. Of the different calcium phosphate materials tested, TCP and TCP (s) facilitated osteoblast growth and extracellular matrix elaboration to the highest degree, followed by Biocements H and F. The inhibition of cell growth encountered with R 5 seems to be related to its high phosphate and potassium ion release.

Rapid analysis of O-acetylated neuraminic acids by matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

N-Acetylneuraminic acid (a sialic acid) occurs mainly as a terminal substituent of oligosaccharides of glycoconjugates. Derivatives of neuraminic acid occur widely, substituted in the amino and hydroxy side chains, as well in the C-9 carbon skeleton. These derivatives are responsible for specific functions of sialic acids during cell-cell, cell-substrate, or cell-virus interactions. The study of O-acetylated neuraminic acids is difficult, because only small amounts are extractable from natural sources and they are generally unstable to acids and bases. We report a new method for the rapid analysis of O-acetylated neuraminic acids, using a combination of reversed phase HPLC and MALDI-TOF mass spectrometry. A mixture of neuraminic acids from bovine submaxillary gland mucins was analysed, as well as neuraminic acids variously substituted in the amino and hydroxy side chains with acetyl and glycolyl groups, respectively.

Serum cardiac troponin T as a prognostic marker in early sepsis.

STUDY OBJECTIVE: Sepsis is the leading cause of death in the noncardiologic ICU. Maldistributed nutritive blood flow and altered convective and diffusive oxygen transport during sepsis can lead to organ dysfunction and multiple organ failure. One of the causes of myocardial dysfunction is thought to be myocardial ischemia in sepsis; however, conventional biochemical parameters to detect myocardial ischemia lack sensitivity and specificity. Serum cardiac troponin T (S-TnT) was reported to have higher sensitivity and specificity in diagnosing minor myocardial injury. The aim of this study was to investigate if and how often S-TnT is pathologically elevated in patients with sepsis and to evaluate whether S-TnT might be a prognostic marker in early sepsis. DESIGN: Prospective study. SETTING: Surgical ICU. PATIENTS: Twenty-six patients with sepsis were included in this study within 24 h of the onset of sepsis. The patients were allocated a priori to a high S-TnT group (S-TnT > or = 0.2 microg/L) and a low S-TnT group (S-TnT<0.2 microg/L). MEASUREMENT: Blood samples for the determination of S-TnT and conventional myocardial ischemia markers as well as for adhesion molecules were drawn. Hemodynamic measurements were performed every 4 h during the first 24 h and then once per day over 7 days. S-TnT was determined by enzyme-linked immunosorbent sandwich assay. RESULTS: Eighteen patients had pathologically high S-TnT values. High S-TnT values were associated with an increased mortality rate (15/18 in the high S-TnT group vs 3/8 in the low S-TnT group; p=0.02). Significant differences between the two groups were found in the norepinephrine dosages at maximum values of S-TnT. Soluble intercellular adhesion molecule-1 was significantly elevated in the high S-TnT group. CONCLUSIONS: As high S-TnT values were associated with an increased mortality rate, it seems reasonable to further evaluate S-TnT as a prognostic marker of myocardial ischemia in patients with sepsis under different therapeutic regimens.

In vitro investigation of novel calcium phosphates using osteogenic cultures.

A rat bone marrow stromal cell (RBM) culture was used to evaluate novel bioactive calcium phosphate ceramics. Three rapidly resorbable, glassy crystalline materials with the main crystalline phase Ca2KNa(PO4)2 were investigated (sample code GB 1a, GB 14, GB 9). These materials were designed to exhibit a higher degree of biodegradability than tricalcium phosphate. Additionally, a bioactive glass ceramic of low biodegradability was examined (sample code AP 40). RBM cells were cultured on the disc-shaped test substrata for 14 d. The culture medium was changed and calcium and phosphate concentrations of the medium were determined daily. Specimens were evaluated using light microscopy and morphometry of the cell-covered substrate surface, scanning electron microscopy and energy dispersive X-ray analysis. Except for GB 1a, the rat bone marrow cells attached and grew on all substrate surfaces. Of the different calcium phosphate ceramics tested, AP 40 facilitated osteoblast growth and the elaboration of the extracellular matrix to the highest degree followed by GB 9 and GB 14. The inhibition of cell growth encountered with GB 1a seemed to be related to its high phosphate ion release.

Morphological evaluation of osteoblasts cultured on different calcium phosphate ceramics.

The objective of these investigations was to develop an in vitro test system for evaluating novel rapidly resorbable calcium phosphate ceramics of varying composition. Rat bone marrow cells were cultured on the disc-shaped test substrates for 14 days. Five calcium phosphates were examined: R1 CaNaPO4; R1/M2, composed of CaNaPO4 and MgNaPO4; R1/2, composed of CaNaPO4 and Mg2SiO4; R1 + 9% SiO2 consisting of CaNaPO4 and 9% SiO2 (wt%) and R17, Ca2KNa(PO4)2. Two studies were performed. In study I cultures were re-fed every two to three days. In study II the medium was changed daily, and calcium and phosphate concentrations of the medium were determined daily. Specimens were prepared for light microscopy and morphometric evaluation of the cell-covered substrate area, scanning electron microscopy and energy-dispersive X-ray analysis. With all materials tested except for R1/2, an increase of cellular growth was observed after changing the medium daily. Of the different calcium phosphate ceramics tested, R17 and R1/M2 facilitated osteoblast growth and elaboration of extracellular matrix to the highest degree. The inhibition of cell growth encountered with R1 in study I and R1/2 in both studies seemed to be related to a high phosphate-ion release from these materials.

Endogenous inhibitors of 11 beta-OHSD: existence and possible significance.

Inhibition of 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) by licorice-derived compounds and in cases of idiopathic impairment of this enzyme is known to result in hypermineralocorticoid syndromes, reflecting corticosteroid receptor activation by excess intracellular glucocorticoids. In this paper we address the question of whether or not endogenous inhibitors of 11 beta-OHSD exist that might cause pathological glucocorticoid metabolism. Using microsomal preparations we have demonstrated that bile acids are potent inhibitors of rat renal and human hepatic 11 beta-OHSD, with lithocholic acid exerting the strongest effect. The human renal enzyme is affected to a lesser extent. Serum of patients with cholestatic liver cirrhosis also inhibited 11 beta-OHSD activity, in parallel with total bile acid concentration. Cholesterol and its precursor lanosterol inhibited the enzymatic activity in microsomes from rat and human kidney cortex and human liver. We conclude that bile acids could contribute to the abnormalities of cortisol metabolism observed in cholestatic liver cirrhosis.

The status, distribution and ecology of wildlife on the U.S. Doe Hanford Site: A historical overview of research activities.

Since the inception of the U.S. DOE Hanford Site in 1943, numerous studies have been conducted on terrestrial wildlife. Onsite contractors have focused their attention on the role of wildlife in the uptake and transport of radionuclides. Graduate students from across the nation have also completed more than 15 theses on wildlife. This paper discusses the past history of wildlife research at Hanford and the individual species of wildlife that have been observed at Hanford. Forty species of mammals, 187 species of birds, 3 species of amphibians and 9 species of reptiles have been documented on the Hanford Site to date.

Serum neopterin levels in lung and breast cancer patients undergoing radiotherapy and/or chemotherapy.

The elevated neopterin levels observed in numerous haemotological diseases and parenchymatous malignomas suggested neopterin might be useful as a tumor marker. In a group of 60 patients suffering from advanced lung (18) or breast (42) cancer, serial determinations of serum neopterin were made before, during and after radiation and/or chemotherapy, during an observation period of 18 months, to check the potential value of neopterin in the therapeutic management of these tumor types. The neopterin profiles were compared with the clinical course and analysed with regard to response to therapy. Numbers of pathologically elevated serum neopterin levels were low. In only few cases was any agreement detected between changes in neopterin levels and therapeutic effects. Even chemotherapeutically induced depression in white blood counts generally did not increase serum neopterin levels. Thus the clinical suitability of neopterin as an adjuvant parameter in assessing therapeutic effects in lung or breast cancer could not be documented.

[The effect of thoracic peridural analgesia on the cortisol and glucose response in surgery of the abdominal aorta]. / Die Auswirkungen der thorakalen Periduralanalgesie auf die Kortisol- und Glukoseantwort bei Operationen an der abdominellen Aorta.

UNLABELLED: It has been shown that the stress response to lower abdominal surgery can be inhibited by epidural analgesia (EA). But EA seems to have little influence on the stress reaction to major abdominal surgery. The purpose of our study was to find out whether EA is able to diminish the cortisol and glucose response to major transabdominal surgery. METHODS: 31 patients undergoing elective surgery of the abdominal aorta were subdivided at random into 3 different anaesthesia groups: 1. halothane anesthesia, 2. neuroleptanalgesia (NLA) and 3. thoracic EA with bupivacaine (0.5%) in combination with a light general anesthesia. Some patients of each group received an intravenous infusion of 5% glucose. Blood samples were drawn before anesthesia, after intubation, 5 times during surgery and at the end of the operation and were analysed for cortisol and glucose. During the early postoperative period, 1, 2 and 24 h after surgery, only cortisol was measured. RESULTS: Only the glucose levels of patients who received no carbohydrate-containing infusion fluids were used for evaluation of the stress response. In the halothane group, there was a significant increase of the mean cortisol and glucose levels after the start of surgery. No intraoperative elevations of blood glucose and cortisol were seen in the EA group. Patients of the NLA group showed no hyperglycaemia and only mild elevations of the cortisol levels during the intraoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated tumor markers in hemodialysis patients.

The incidence of elevated tumor markers without clinical signs of malignant disease was examined in 93 patients between the age of 29 and 79 years and on chronic dialysis for 3-240 months. Tissue polypeptide antigen was found to be elevated in 92.5%, carcinoembryonic antigen in 29.8, and alpha-fetoprotein in 6.5%. High levels of tissue polypeptide antigen were accompanied by high levels of beta 2-microglobulin (p less than 0.005). This indicates that tumor markers, and tissue polypeptide antigen in particular, may be unreliable for monitoring malignant disease in patients on hemodialysis.

Acute acid load in recurrent oxalate stone formers.

An acute acid load was used to evaluate potential chemical differences of urinary composition in recurrent oxalate stone formers and healthy controls. After intake of ammonium chloride, total calcium, ionized calcium and magnesium increased and citrate decreased significantly in both groups. Differences between stone formers and controls could be demonstrated from the excretion of total calcium, citrate, oxalate and uric acid only after acute acid load, whereas ionized calcium did not improve discrimination. These findings support the stone-promoting role of high acid food as well as the possibility of discriminating recurrent oxalate stone formers from controls by an acute acid-loading test.

Effect of dialyzer membranes on in vitro generation of eicosanoids.

Eicosanoids are potent substances released from blood cells after contact with foreign materials. Eicosanoid generation, in addition to complement fragment formation, may be a valuable indicator of the biocompatibility of dialyzer membranes. In the present in vitro study, eicosanoid generation induced by several different flat dialyzer membranes [polyacrylonitrile (PAN), cuprammonium cellulose (CC), and polycarbonate (PC)] was evaluated and compared using blood from non-uremic healthy volunteers. Generation of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) was greatest with PC followed by PAN and CC. The formation of C3a des arg with PAN was less than with either CC or PC. Our results suggest that dialyzer membranes affect complement activation and eicosanoid generation differently; biocompatibility as expressed by a low level of complement fragment formation does not necessarily translate into biocompatibility when considering eicosanoid generation.

Clinical experience with the tumor marker Ca 19-9 in an unselected group of more than 300 tumor patients.

Since March, 1983, in vitro tests for the quantitative determination of the tumor-associated antigen Ca 19-9 (carbohydrate antigen 19-9) were performed in more than 300 patients with confirmed tumors. These tests had as a goal determination of the diagnostic value of this new potential tumor marker Ca 19-9 with regard to specificity and sensitivity of malignant growths in the gastrointestinal tract, breast, and lung. The applicability of Ca 19-9 RIA in posttherapeutic case control for early registration of recurrences and metastases was examined. First analyses of our patient collective confirmed the assumption that increased serum concentrations of Ca 19-9 are detectable in gastrointestinal tumors as well as in mammary and bronchial carcinoma. Thus Ca 19-9 is a nonspecific tumor-associated antigen that by itself does not allow an organ correlation of malignancies of the gastrointestinal tract, breast, and lung.

Nuclear fuel-cycle radionuclides in raptor castings: implications for environmental monitoring.

Our sampling results indicate that raptor castings (regurgitated material containing the nondigestible remains of prey) faithfully reflect the composition of known environmental gamma-emitting radionuclides. The castings are easily obtainable and provide a way to monitor for the presence of biologically available radionuclides. Raptor castings can also provide a useful adjunct to existing monitoring programs where small mammal burrowing into buried waste may occur.

Excrement from Heron colonies for environmental assessment of toxic elements.

Excrement cast from Great Blue Heron nests was collected during the nesting period of 1978 from four colonies in Washington and Idaho. Cheesecloth strips placed on the ground beneath the nests served as excrement collecting devices. Chemical analysis for lead, mercury and cadmium were performed on dried samples. Lead was the most abundant trace metal found in heron debris. The Idaho colony at Lake Chatcolet had an average concentration of 46 ppm in the beneath-nest samples and 6 ppm in control samples. A heron colony near Tacoma, Washington had beneath-nest samples averaging 28 ppm and control samples averaging 20 ppm. Two colonies located in the interior region of Washington had substantially lower concentrations of lead. The difference observed between colonies was attributed to their associations with a polluted watershed (Chatcolet colony) an interstate highway (Tacoma colony) and an unpopulated largely agricultural area (inland Washington).