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The determination of what physical measure of absorbed low-level radiation is best correlated with cellular change, including mutation or cell death, is a controversial issue. The method devised by the Medical Internal Radiation Dose (MIRD) Committee typically assumes that all cells in an irradiated organ receive the same amount of radioactivity, an assumption that may not be valid. The sensitivity of different cell types within the same region may differ considerably, and, in addition, some radioactive agents concentrate preferentially around certain cell types. Radiolabeled (radioactive) technetium 99m, commonly used in imaging studies of the liver and spleen, appears to be absorbed much more by some cells (macrophages, a type of blood cell) than would be calculated according to a model that assumes homogeneous distribution. Absorbed doses in lung cells are calculated for two agents used to perfuse (fill the blood vessels) the lung, technetium 99m-labeled microspheres (average diameter, 25 microns) and technetium 99m-labeled macroaggregates (average diameter, 40 microns). Dosages were calculated for emitted electrons and photons (two kinds of subatomic particles). The probable path and location of the particles through and in the lung were taken into account by the model. The method is explained in detail. Results showed that this approach leads to calculated dosages of approximately one-fourth the value obtained using the MIRD method for most (92 percent) of the cells in the lung; it also leads to dosages between three and 7,500 times higher for the remaining cells. Although the implications for risk that may be derived from these findings cannot be evaluated, these results should lend impetus to attempts to develop dosimetric (radiation dose calculation) methods that include the heterogeneity of human tissue in their calculations. (Consumer Summary produced by Reliance Medical Information, Inc.)

Abstract Background We present an effective, rapid, systematic data mining approach for identifying genes or proteins related to a particular interest. A selected combination of programs exploring PubMed abstracts, universal gene/protein databases (UniProt, InterPro, NCBI Entrez), and state-of-the-art pathway knowledge bases (LSGraph and Ingenuity Pathway Analysis) was assembled to distinguish enzymes with hydrolytic activities that are expressed in the extracellular space of cancer cells. Proteins were identified with respect to six types of cancer occurring in the prostate, breast, lung, colon, ovary, and pancreas. Results The data mining method identified previously undetected targets. Our combined strategy applied to each cancer type identified a minimum of 375 proteins expressed within the extracellular space and/or attached to the plasma membrane. The method led to the recognition of human cancer-related hydrolases (on average, ~35 per cancer type), among which were prostatic acid phosphatase, prostate-specific antigen, and sulfatase 1. Conclusion The combined data mining of several databases overcame many of the limitations of querying a single database and enabled the facile identification of gene products. In the case of cancer-related targets, it produced a list of putative extracellular, hydrolytic enzymes that merit additional study as candidates for cancer radioimaging and radiotherapy. The proposed data mining strategy is of a general nature and can be applied to other biological databases for understanding biological functions and diseases.

The increased awareness of the rights of dying patients has been translated into new laws; a patient's right to refuse medical treatment has been upheld in numerous court decisions. Popular attitudes about the rights of dying patients have changed, often in advance of the attitudes of health care providers, legislators, and the courts. Physicians must have timely discussions with patients about life-sustaining treatment and terminal care, and become familiar with patients' personal values and wishes, documenting them as they document information about medical history. Dying at home can provide the opportunity for quiet, privacy, dignity, and family closeness that may make death easier for the patient and provide consolation for the bereaved. Home care should be guided by the physician and implemented with the help of well-trained personnel from hospice units that now serve many communities. Care of the dying demands constant adjustment to pain control, fear and suffering. If pain cannot be controlled with the commonly used analgesic drugs more potent narcotics should be prescribed. Even as death approaches, and curative techniques are not required, sensitivity and responsibility to the patient and their family, are needed. With compassionate care patients will be less likely to commit suicide which differs from euthanasia in that the act of bringing on death is performed by the patient, not the physician. The physician who considers aiding a patient's suicide must determine first that the patient is indeed beyond all help and not suffering from a treatable depression, common in those with terminal illnesses. Even though suicide itself is not illegal, helping a person commit suicide is a crime in many states. No physician has ever been prosecuted in the U.S. for prescribing pills in order to help a patient commit suicide. Euthanasia, is being widely discussed in the U.S., but the prospect of criminal prosecution deters even the strongest physician advocates of this practice.