Transrectal ultrasound and biopsy in the early diagnosis of prostate cancer.

BACKGROUND: Historically, the prostate was evaluated for cancer by simple digital rectal examination, and biopsy to obtain a tissue diagnosis of cancer was performed blindly. The advent of ultrasound technology offered a new way to evaluate the prostate, and biopsy techniques were soon developed to incorporate ultrasound guidance. METHODS: The authors review the role of transrectal ultrasound (TRUS) of the prostate and ultrasound-guided biopsy of the prostate in the diagnosis of prostate cancer. These techniques are traced from their origins to the current standards of care, with attention paid to developments and controversies in recent literature. RESULTS: Early experience with TRUS led to the description of "classic" sonographic findings of prostate cancer. To obtain a tissue diagnosis of cancer, these regions were initially targeted in ultrasound-guided biopsies. Concomitant with the development of TRUS, though, was the development of the prostate-specific antigen (PSA) assay. Over the past decade, there has been a profound stage migration due to earlier detection of prostate cancer. Most patients now diagnosed with prostate cancer have no palpable abnormality or specific sonographic findings. In response, ultrasound-guided biopsies have become more systematic, rather than lesion-specific, in nature. CONCLUSIONS: TRUS continues to play an important role in the evaluation of the prostate when malignancy is suspected. Although the optimal method of prostate biopsy is controversial, ultrasound is critical in ensuring accurate sampling of the gland.

Glycolate metabolism by Hep G2 cells.

The pathways of oxalate synthesis in humans are not well defined despite their clinical significance in primary hyperoxaluria and idiopathic calcium oxalate nephrolithiasis. Furthermore, the functional roles, if any, of this synthesis have not been elucidated. This study examines pathways of oxalate synthesis from glycolate in Hep G2 cells, a human hepatoma cell line. Incubation of these cells with glycolate has revealed that a pathway may function to synthesize oxalate from glycolate that does not depend on the oxidation of glycolate to glyoxylate by glycolate oxidase. Labeling cells with 14C-glycolate and chromatographic analyses indicated that detectable amounts of 14C-glyoxylate were not formed. A radioactive peak that coeluted with oxalate on ion exclusion chromatography was the only peak yet identified. A detailed examination of glycolate metabolism in these cells should help clarify the terminal steps associated with oxalate synthesis and aid in our understanding of two-carbon metabolism.

Recurrent suture urolithiasis 29 years after open pyelolithotomy.

A case of a foreign body-induced renal stone in which the patient was treated successfully with a ureterorenoscopic approach is presented.