David Robert Siemens

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PURPOSE Topical steroids have been advocated as an effective economical alternative to circumcision in boys with phimosis. We evaluated the effectiveness of topical steroid therapy as primary treatment in 194 patients with phimosis. METHODS Between January 1996 and November 2000, 228 boys 16 years old or younger were referred for consideration of(More)
BACKGROUND Most early stage kidney cancers are renal cell carcinomas (RCCs), and most are diagnosed incidentally by imaging as small renal masses (SRMs). Indirect evidence suggests that most small RCCs grow slowly and rarely metastasize. OBJECTIVE To determine the progression and growth rates for newly diagnosed SRMs stratified by needle core biopsy(More)
BACKGROUND An observed decrease of physician scientists in medical practice has generated much recent interest in increasing the exposure of research programs in medical school. The aim of this study was to review the experience and attitudes regarding research by medical students in Canada. METHODS An anonymous, cross-sectional, self-report questionnaire(More)
An important aspect of malignant progression is the acquired ability of tumor cells to avoid recognition and destruction by the immune system (immune escape). Clinical cancer progression is also associated with the development of tumor hypoxia, which is mechanistically linked to the acquisition of malignant phenotypes in cancer cells. Despite the(More)
PURPOSE Hypoxia contributes to drug resistance in solid cancers, and studies have revealed that low concentrations of nitric oxide (NO) mimetics attenuate hypoxia-induced drug resistance in tumor cells in vitro. Classic NO signaling involves activation of soluble guanylyl cyclase, generation of cyclic GMP (cGMP), and activation of cGMP-dependent protein(More)
OBJECTIVE MicroRNAs (miRNAs) are part of a class of small ribonucleic acid (RNAs). They are important regulatory molecules, involved in several cell processes, such as developmental timing, stem cell division and apoptosis. Dysregulated miRNAs have been identified in several human malignancies, including bladder cancer tissue samples, and may confer a(More)
PURPOSE We provide a baseline description of men diagnosed with chronic epididymitis, explore relevant associations that may be important etiological factors and suggest a classification system and specific symptom assessment tool. MATERIALS AND METHODS Men diagnosed with chronic epididymitis, described as symptoms of discomfort or pain at least 3 months(More)
OBJECTIVES To evaluate the effect of low-dose glyceryl trinitrate (GTN) on men with biochemical recurrence of prostate cancer after primary therapy. Preclinical, proof-of-principle studies have demonstrated that nitric oxide signaling plays a significant role in the hypoxia-induced progression of prostate cancer. METHODS A prospective, open-label clinical(More)
One key to malignant progression is the acquired ability of tumor cells to escape immune-mediated lysis. Whereas tumor hypoxia is known to play a causal role in cancer metastasis and resistance to therapy, the link between hypoxia and immune escape in cancer remains poorly understood. Here, we show that hypoxia induces tumor cell resistance to lysis(More)
OBJECTIVE To describe lymph node counts in routine clinical practice and evaluate their association with outcomes to explore its utility as a quality indicator. METHODS AND MATERIALS Electronic records of treatment and surgical pathology reports were linked with the population-based Ontario Cancer Registry to identify all patients who underwent cystectomy(More)