Enhanced aggregability of human red blood cells by diving.

In vitro studies have shown that mild pressure increases red blood cell (RBC) aggregation. Enhanced RBC aggregation in pathologic states can drive the circulation into stasis. This investigation examined the effects of pressure on RBC aggregation in human volunteers. The hypothesis tested is that RBC aggregation is increased during hyperbaric exposure. Eleven subjects participated in dives to 300 feet of seawater (fsw) in a man-rated chamber complex. Blood samples were taken at the surface, at 66 fsw, and at 300 fsw. Data were analyzed with a repeated measures one-way analysis of variance for a complete randomized design. Statistical significance was achieved at P < 0.05. Data are expressed as mean +/- SEM. The median aggregate size (number of RBC/aggregate) of RBCs was significantly increased at depth. At a shear stress of 0.1 dyne/cm2, median aggregate size was 12.0 +/- 2.1, 33.0 +/- 7.3, and 48.8 +/- 10.8 at the surface, at 66 fsw, and at 300 fsw, respectively. These results show that mild pressure increases RBC aggregation in the human circulation.

Prognostic variables in osteosarcoma: a multi-institutional study.

This is a report of a multi-institutional study of all patients with osteosarcoma who were seen at 13 comprehensive cancer centers from July 1, 1977, to December 31, 1982. Follow-up extended to 9 years; a minimum of 3 years was obtained for greater than 90% of the patients. All patients with osteosarcoma were considered, but only those with tissue confirmation who had had at least part of their first course of treatment at one of the 13 institutions were included. There were 543 patients. In a search for prognostic indicators, 38 patient characteristics, three treatment categories, and an institutional variable were studied. A combination of nine of these constituted the best indicator of survival. They were morphology (two parts), site of primary cancer (two parts), spread of tumor, grade and size of tumor, duration of symptoms, weight loss of greater than 4.5 kg (10 lb), swelling at primary site, and lytic appearance. Unexpectedly, treatment was not one of the indicators of survival. A prognostic score was developed in which the coefficients were obtained from the Cox regression (step-down) method. Each patient had a score (S) and an observed survival time that together provided the expected risk of death for that patient. Although this was not a randomized study, treatments were compared before and after adjusting for characteristics identified as prognostic. Three treatments differed little: surgery alone, surgery plus chemotherapy and/or radiotherapy, and chemotherapy and/or radiotherapy followed in 1-4 months by surgery. Patients with amputations and those with resections had similar death rates, but the observed progression rates differed widely. However, when the rates were adjusted for prognostic characteristics, the difference disappeared. Complete surgery (if osteosarcoma existed within surgical margins) was no better than incomplete surgery (if osteosarcoma existed beyond surgical margins) with respect to death but, as would be expected, complete surgery was much better with respect to disease progression.

Barium enemas of carcinoma of the colon: sensitivity of double- and single-contrast studies.

A total of 1,140 primary colorectal carcinomas found in 1084 patients during a 5 1/2-year period (1976 to mid-1981) at the Mayo Clinic was reviewed to evaluate the accuracy of detection by the double- and single-contrast barium enema examinations. Both methods were equally sensitive in detecting colon cancer above the proctoscopic level. The error rate (ulcerative colitis excluded) was 4.8% for the single-contrast enema and 4.7% for the double-contrast study. Neither type of examination was superior in finding smaller lesions or earlier staged lesions. Several causes for error were identified: fluoroscopic inexperience, technical factors, misinterpretation of radiologic findings, and distraction.

U.S. centralized cancer patient data system for uniform communication among cancer centers.

The evolution of the Centralized Cancer Patient Data System, a cooperative venture of the 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that ae 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that ae 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that are comparable among cancer centers has been largely accomplished. Moreover, the very process of setting up the national data system has benefited the participating centers by upgrading their individual cancer registries. For the future, the goal is to realize the research potential of this new cooperative data collection mechanism, as well as the accumulating data themselves. Progress toward the long-term goal is just beginning.

High-dose methotrexate with a safe rescue program.

23 patients with osteogenic sarcoma were observed during 142 6-hour high-dose infusions of methotrexate (MTX, 3,000--8,200 mg/m2). Calcium leukovorin was given by intravenous injection at 3-hour intervals beginning 2 h after the completion of each MTX infusion with extension of the intervals to 6 h following the first day of rescue. All patients also received continuous intravenous infusions of alkalinized fluids for the entire duration of leukovorin rescue. No larger doses of leukovorin were given to any patient. Three of the 142 MTX infusions resulted in mild cytotoxic side effects. Plasma MTX clearance ranged from 90 to 600 ml/min among the 62 infusions where plasma clearance could be accurately calculated. The 3 patients with mild toxicity had low drug clearance, but others with similar low MTX clearance experienced no apparent toxic effects beyond the expected transient nausea.