Relationship of aneurysmal subarachnoid hemorrhage to changes in atmospheric pressure: results of a prospective study

OBJECT: The purpose of this study was to evaluate the relationship between atmospheric pressure and subarachnoid hemorrhage (SAH) in a region in the English Midlands. METHODS: All patients with angiographically proven SAH for the calendar year 1998 were analyzed. A geographical allocation was made based on the patients' origin within the region. The events were then compared with the data available for the local atmospheric pressures. One hundred nine patients had an SAH during the time period studied. The median atmospheric pressure recorded was 1014.5 millibars. Atmospheric pressure was modestly correlated with the number of SAHs per day (Spearman's rank correlation, r = 0.33; p < 0.0001); the daily change in atmospheric pressure also correlated mildly (r = 0.34, p < 0.0001). No other statistically significant association was found. CONCLUSIONS: The authors have shown a relationship between high atmospheric pressure and increased incidence of SAH. The underlying reason for this remains obscure.     

A new amino acid mixture permits new approaches to the treatment of phenylketonuria

A new amino acid mixture for incorporation into medical foods for the treatment of hyperphenylalaninemia has been tested in a regular clinic. The mix is designed to be as unobtrusive as possible, consistent with good nutrition. After more than 1 year of trial as a beverage, we have shown that it is safe and well tolerated but that plasma phenylalanine is no better controlled than with some other products. The mix can be incorporated into a large number of different foods without affecting the taste. Occult monitoring of the quantity of medical foods purchased compared with the amounts reported to be consumed in diet histories provides an excellent way to monitor dietary compliance.     

Somatic cell hybrids for high-density mapping of chromosome 2 breakpoints in radiation-induced myeloid leukemia cell lines from inbred mice

Chromosome 2 (chr 2) deletions are recurrent abnormalities in acute myeloid leukemia (AML) induced by ionizing radiation in the mouse. The localization of deletion sites has proven extremely useful in providing information on the molecular mechanisms of leukemogenesis. The models available for the study of AML are mostly represented by inbred mouse strains, in which the molecular resolution of breakpoints is problematic. In this study, we have examined five leukemic cell lines exhibiting hemizygous chr 2 loss, derived from CBA, C3H, or (C57BLxCBA/H) F1 mice in which AML had been induced by a whole-body dose of radiation. By application of a somatic cell hybridization technique, we have generated interspecific cell hybrids retaining the deleted murine chr 2 homologue. This strategy permitted a very detailed genetic analysis allowing the utilization of any genetic marker on chr 2 without a requirement for polymorphism. Somatic cell hybrid clones were subjected to a high-density polymerase chain reaction-based microsatellite screening using 62-106 informative markers for each cell line. Detailed maps accurately defining chr 2 breakpoints were obtained. The identification of critical breakpoint markers allowed the construction of partial yeast artificial chromosome contigs across chr 2 breakpoints. These maps represent an essential resource for cloning of the breakpoint regions.     

Supraacetabular insufficiency fractures

Insufficiency fractures in the supraacetabular region were identified in five women, aged 55-83 years. Factors contributing to the diminished resistance of their bones included postmenopausal osteoporosis, steroid therapy, radiation therapy, and rheumatoid arthritis. The supraacetabular fractures were seen on routine radiographs as hazy bands of sclerosis located immediately above and parallel to the acetabular roof. All five patients had additional fractures in the spine or pelvis. Supraacetabular insufficiency fractures may be an unsuspected cause of hip pain, especially in older women.