Bone Health Monitoring in Astronauts: Recommended Use of Quantitative Computed Tomography [QCT] for Clinical and Operational Decisions

This slide presentation reviews the concerns that astronauts in long duration flights might have a greater risk of bone fracture as they age than the general population. A panel of experts was convened to review the information and recommend mechanisms to monitor the health of bones in astronauts. The use of Quantitative Computed Tomography (QCT) scans for risk surveillance to detect the clinical trigger and to inform countermeasure evaluation is reviewed. An added benefit of QCT is that it facilitates an individualized estimation of bone strength by Finite Element Modeling (FEM), that can inform approaches for bone rehabilitation. The use of FEM is reviewed as a process that arrives at a composite number to estimate bone strength, because it integrates multiple factors

Medical complications of aneurysmal subarachnoid hemorrhage: A report of the multicenter, cooperative aneurysm study

OBJECTIVESThis report examines the frequency, type, and prognostic factors of medical (nonneurologic) complications after subarachnoid hemorrhage in a large, prospective study. The influences of contemporary neurosurgical, neurological, and critical care practice on mortality and morbidity rates after aneurysmal subarachnoid hemorrhage are evaluated. DESIGNA study of medical complications observed in the placebo limb of a large, randomized, controlled trial of the calcium antagonist, nicardipine, after subarachnoid hemorrhage. SETTINGPatients were recruited from 50 hospitals in 41 neurosurgical centers in the United States and Canada. PATIENTSA total of 457 patients with subarachnoid hemorrhage, >or=to18 yrs of age, were randomly assigned to the placebo group. All patients arrived at the participating center within 7 days (mean 1.0 +/- 1.8 [SD] days) of rupture of an angiographically documented saccular aneurysm. MEASUREMENTS AND MAIN RESULTSThe frequency rates of symptomatic vasospasm, rebleeding, and total mortality rate after subarachnoid hemorrhage at 3-month followup were 46%, 7%, and 19%, respectively. The frequency of having at least one severe (life-threatening) medical complication was 40%. The proportion of deaths from medical complications was 23%. This value was comparable with the proportion of deaths attributed to the direct effects of the initial hemorrhage (19%), rebleeding (22%), and vasospasm (23%) after aneurysmal rupture. The frequency of life-threatening cardiac arrhythmias was 5%; less ominous rhythm disturbances occurred in 30% of the patients. There was an increased frequency of cardiac arrhythmias on the day of, or day after, aneurysm surgery. Pulmonary edema occurred in 23% of the patients, with a 6% occurrence rate incidence of severe pulmonary edema. There was a wide variation from center to center, with the greatest frequency on days 3 through 7. There was a nonsignificant association of pulmonary edema with the use of hypertensive hypervolemic therapy (p = .10), and a significant association with the timing of surgery (p < .05). Some degree of hepatic dysfunction was noted in 24% of patients, the majority with only mild abnormalities of hepatic enzymes with no clinical accompaniment (4% frequency of severe hepatic dysfunction). Thrombocytopenia occurred in 4% of patients, usually in the setting of sepsis. Renal dysfunction was reported in 7% of the patients, with 15% of that figure deemed to be of life-threatening severity. There was an association (p = .001) with antibiotic therapy. CONCLUSIONSPotentially preventable medical complications after ruptured cerebral aneurysm add to the total mortality rate of patients, and may increase length of hospital stay in the critical care setting. The proportion of deaths after subarachnoid hemorrhage from medical complications equals those deaths from either direct effects, rebleeding, or vasospasm individually. Pulmonary complications are the most common nonneurologic cause of death. Cardiac arrhythmia, although frequent, was not associated with significant mortality. The frequency of cardiac arrhythmia and pulmonary edema increased on the day of, or day after, aneurysm surgery. Renal and hepatic dysfunction, and blood dyscrasias, were also observed, underscoring the need for meticulous monitoring for metabolic and hematologic derangements.(Crit Care Med 1995; 23:1007-1017

Nuclear morphology predicts cell survival to cisplatin chemotherapy

The emergence of chemotherapy resistance drives cancer lethality in cancer patients, with treatment initially reducing overall tumor burden followed by resistant recurrent disease. While molecular mechanisms underlying resistance phenotypes have been explored, less is known about the cell biological characteristics of cancer cells that survive to eventually seed the recurrence. To identify the unique phenotypic characteristics associated with survival upon chemotherapy exposure, we characterized nuclear morphology and function as prostate cancer cells recovered following cisplatin treatment. Cells that survived in the days and weeks after treatment and resisted therapy-induced cell death showed increasing cell size and nuclear size, enabled by continuous endocycling resulting in repeated whole genome doubling. We further found that cells that survive after therapy release were predominantly mononucleated and likely employ more efficient DNA damage repair. Finally, we show that surviving cancer cells exhibit a distinct nucleolar phenotype and increased rRNA levels. These data support a paradigm where soon after therapy release, the treated population mostly contains cells with a high level of widespread and catastrophic DNA damage that leads to apoptosis, while the minority of cells that have successful DDR are more likely to access a pro-survival state. These findings are consistent with accession of the polyaneuploid cancer cell (PACC) state, a recently described mechanism of therapy resistance and tumor recurrence. Our findings demonstrate the fate of cancer cells following cisplatin treatment and define key cell phenotypic characteristics of the PACC state. This work is essential for understanding and, ultimately, targeting cancer resistance and recurrence