Invited article: advanced drag-free concepts for future space-based interferometers: acceleration noise performance

Future drag-free missions for space-based experiments in gravitational physics require a Gravitational Reference Sensor with extremely demanding sensing and disturbance reduction requirements. A configuration with two cubical sensors is the current baseline for the Laser Interferometer Space Antenna (LISA) and has reached a high level of maturity. Nevertheless, several promising concepts have been proposed with potential applications beyond LISA and are currently investigated at HEPL, Stanford, and EADS Astrium, Germany. The general motivation is to exploit the possibility of achieving improved disturbance reduction, and ultimately understand how low acceleration noise can be pushed with a realistic design for future mission. In this paper, we discuss disturbance reduction requirements for LISA and beyond, describe four different payload concepts, compare expected strain sensitivities in the "low-frequency" region of the frequency spectrum, dominated by acceleration noise, and ultimately discuss advantages and disadvantages of each of those concepts in achieving disturbance reduction for space-based detectors beyond LISA.

Non-pulmonary factors affecting survival in patients completing pulmonary rehabilitation

Patients referred to pulmonary rehabilitation usually have advanced chronic obstructive lung disease (COPD). This disease is a common cause of death in developed countries, ranking fourth as a cause of death in the United States, behind heart disease, cancer, and stroke. The three-year survival following outpatient pulmonary rehabilitation is approximately 80%. Clearly, markers of disease severity such as the degree of airways obstruction, arterial blood gas abnormality, degree of pulmonary hypertension, and the need for hospitalizations predict mortality in this disease. However, because of substantial co-morbidity, patients with COPD often die with their disease rather than from their disease. Thus, only 45 to 63% of deaths in patients with advanced lung disease are directly due to the disease itself. Factors other than primary disease severity that predict mortality in COPD include nutritional depletion, exercise endurance, functional performance, and even social factors such as marital status. Thus, once the chronic lung disease progresses to the point where referral is made to pulmonary rehabilitation, non-pulmonary factors are also important predictors of survival. This underscores the importance of a holistic approach to the patient with advanced lung disease, and the need for a comprehensive severity grading system that includes more than the forced expiratory volume in 1 sec (FEV1).

Chronic intravenous aminobisphosphonate therapy increases high-density lipoprotein cholesterol and decreases low-density lipoprotein cholesterol

Nowadays, bisphosphonates are considered the drugs of choice for the treatment of several bone disorders. Their exact mechanism of action is not clear but recently it has been reported that the aminobisphosphonates inhibit cholesterol biosynthesis and that this might be relevant for their actions on bone osteoclasts. The study includes 87 postmenopausal women with moderate to severe osteoporosis. The patients were randomly assigned to intravenous (iv) infusion of 50 mg of the aminobisphosphonate Neridronate dissolved in 100 ml of saline solution every 2 months for a year (44 patients). The remaining 43 served as controls. At the time of each infusion blood samples were obtained for the evaluation of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), and total and bone alkaline phosphatase (AP). Free deoxypyridinoline (f-DPD) was measured in fasting urine specimens. In the control group no significant changes were observed throughout the study period for any of the biochemical variables. In the Neridronate-treated patients both bone AP and f-DPD excretion fell significantly by 15-20%. In these patients serum total cholesterol and serum triglycerides showed marginal decreases, which were occasionally significant. LDL-C and Apo B fell by 5-6% and these changes were statistically significant at most time points. Apo A-I and HDL-C rose progressively with time. At the 12th month, HDL-C rose 17-18% (p < 0.0001) above the baseline values. Similar findings were obtained in four postmenopausal women given high iv doses of Pamidronate or Alendronate. In conclusion aminobisphophonates, at least when given iv, induce remarkable and unexpected effects on lipid metabolism with a final profile that might be clinically relevant.

Intramuscular clodronate therapy in postmenopausal osteoporosis

Long-term daily administration of oral bisphosphonates has been effective in the treatment of postmenopausal osteoporosis, but the duration, mode and cost of the therapy may sometimes affect patient compliance. In Italy, the bisphosphonate clodronate is also available via the intramuscular (i.m.) route of administration, and the present study was performed to test its efficacy in postmenopausal osteoporosis. Ninety osteoporotic postmenopausal women were enrolled in a randomized, controlled 3 year study. The diet of all patients was adjusted to provide 1200-1300 mg of calcium daily, eventually by administration of supplements. Patients were randomly assigned to no therapy (30 patients) or to receive clodronate 100 mg i.m. either every 2 weeks (30 patients) or 1 week (30 patients). The i.m. injection caused substantial pain at the site of injection, which led to treatment withdrawal in almost 50% of the patients receiving weekly dosing. In control patients, a progressive, slow decline in spine and femoral bone mineral density (BMD), which became statistically significant at the end of the second year of observation, was observed. In the patients given weekly i.m. clodronate, spinal BMD rose by 3.8% (+/-7.3 SD) within 6 months. A slight, nonsignificant increase was observed thereafter, such that, at the completion of 3 years of observation, the mean gain was 4.5% (+/-6.3). In the patients treated with injections of 100 mg of clodronate every two weeks the increase in BMD was somewhat lower and slower, becoming significant only at month 24 (2.9+/-4.6%). In none of the two active groups was the femoral neck BMD changed significantly during the 3 years of the study. A significant increase in trochanter and Ward's triangle BMD was observed at month 12 only in the patients on the highest dose of clodronate. In both groups treated, the hip BMD changes were significantly different from those observed in control patients. The biochemical markers of bone turnover were suppressed in both clodronate groups. These results indicate that intermittent i.m. clodronate administration can provide clinically relevant benefits to skeletal bone density in osteoporotic postmenopausal women, but the in situ pain may limit its extensive use.

Trends in the incidence of hip fracture in Siena, Italy, from 1980 to 1991

There is general agreement that the crude incidence of proximal femur (hip) fractures is rising in conjunction with the ageing of the underlying population. To explore possible changes in hip fracture incidence over time we analysed all femoral fractures occurring in the county of Siena from 1980 to 1991. Data were collected from hospital record charts of the Department of Orthopaedics, recording all hip fractures occurring during the 12-year period. In this period, the mean resident population in Siena was 238,369 inhabitants (aged 0 to 90+ years) and the crude number of all femoral fractures was 2,238. However, in calculating incidence rates, only hip fractures occurring in the population aged over 50 years were considered. In this population, the number of hip fractures was 1,825 with a male/female ratio of 1:2.8. A time-series data analysis (temporal trend) of the incidence of hip fracture during the 12-year period revealed a linear and significant (p < 0.001) trend to increase, but only in males, with an annual increasing rate of 3.62 per 100,000 person-years. In the female population, the temporal analysis did not show any significant trend during the observation period.

Cytotoxicity of a short-fiber chrysotile asbestos for human alveolar macrophages: preliminary observations

Studies were performed to compare the cytotoxicity for human alveolar macrophages of a naturally occurring short-fiber chrysotile asbestos (RG 144) to that of a standard reference mixed-fiber (long and short) chrysotile asbestos (UICC chrysotile A. Rhodesian). Parallel studies were also performed with quartz (Min-U-Sil 15), a known macrophage toxin. On a mass basis, and after 24 hr incubation, RG 144 was more cytotoxic than the UICC standard reference fiber and less toxic than quartz (silica). The cytotoxic potential of RG 144 chrysotile was further enhanced after size reduction by milling. These findings may have important biologic implications with respect to the use of short-fiber asbestos in industry.