Bladder cancer: a review of diagnosis and management.

Bladder cancer is the fourth most commonly diagnosed malignancy in men and the eighth most common in women. It represents a spectrum of disease, ranging from superficial, well-differentiated disease, which does not significantly impact survival, to highly malignant tumors for which long term survival may be dismal. Transitional-cell carcinoma, which constitutes the vast majority of bladder cancers in the United States, may develop as carcinoma in situ or as invasive carcinoma. This article focuses on transitional-cell carcinoma with a review of the major aspects of the disease, including the epidemiology, diagnosis and staging, and management (including organ preservation). Therapeutic options are explored, including surgery, radiotherapy, chemotherapy, and combined modality therapy.

Radiotherapy in prostate cancer: improvements in an effective treatment and future prospects of further gains.

Radiation therapy has useful applications in the management of all stages of prostate cancer. Modern advances have improved the efficacy of radiotherapy, and have lowered the toxicity. Radiotherapy offers patients with early stage, clinically localized disease a non-invasive curative option that has low toxicity. Patients with metastatic prostate cancer can be palliated with judicious use of radiotherapy.

Use of multiplanar reformatted radiographic and digitally reconstructed radiographic images for planning conformal radiation therapy.

A three-dimensional treatment planning system capable of gantry, collimator, and table rotations is required for a noncoplanar conformal therapy. Unfortunately, such a system is not widely available. A method in which multiplanar reformatted radiographic (MPR) and digitally reconstructed radiographic (DRR) images are used is presented for conformal treatment of brain tumors. A head phantom containing a target volume was scanned on a computed tomographic (CT) simulator. The coronal MPR images were digitized on a treatment planning system to create a conformal block of the planned treatment field. The DRR images were generated on the CT simulator with the setup parameters calculated from the treatment planning system. A second set of conformal blocks was generated based on DRR images of the fields. The accuracy of the MPR- and DRR-generated blocks was verified on the vertex field. The differences between the actual planning target volume and the field edges of the MPR and DRR blocks were within +/- 4 mm and +/- 2 mm, respectively. The authors conclude that the MPR and DRR images could be successfully used to generate conformal blocks and for treatment planning of noncoplanar beams in radiation therapy.

Potassium ion homeostasis and mitochondrial redox activity in brain: relative changes as indicators of hypoxia.

This study was directed at relating ion transport and mitochondrial redox activity during hypoxia, as a step toward definition of brain oxygen sufficiency. To accomplish this, extracellular potassium ion activity (K+o) was recorded by ion-selective microelectrodes while reduction/oxidation (redox) ratios of cytochrome oxidase (cytochrome a,a3) were monitored by reflection spectrophotometry in cerebral cortex of rats anesthetized with pentobarbital. In normoxia, neuronal activation by direct cortical stimulation produced transient oxidation of cytochrome a,a3 and elevation of K+o. Moderate hypoxia (PaO2 above 50 mm Hg) resulted in reduction of cytochrome a,a3 but only slight elevation of K+o. At this level of hypoxia, cytochrome a,a3 continued to respond to neuronal activation with transient shifts toward oxidation and rates of K+o reaccumulation were unchanged from control. When PaO2 was further decreased below a critical threshold, stimulus-provoked oxidative responses of mitochondrial reactants were replaced by shifts toward reduction, but rates of reaccumulation of K+, spilled into the extracellular space by neuronal activation, remained unchanged. Only during severe hypoxia (PaO2 less than 20 mm Hg) was it possible in some animals to record a slowing in the reaccumulation of K+o without provocation of spreading cortical depression. These data indicate that ion transport activity in cerebral cortex is more refractory to hypoxia than is mitochondrial redox functioning. They suggest an in vivo parallel to the "cushioning" effect of mitochondria in vitro, in which oxygen consumption remains constant despite fluctuations in oxygenation and redox ratios, and also that there may be a greater anaerobic capacity to provide energy for ion transport in mammalian brain than has previously been appreciated.