Prostate cancer outcome and tissue levels of metal ions.

BACKGROUND: There are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome. METHODS: We obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case-control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se. RESULTS: Patients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 µg/g vs. 111 µg/g; P = 0.04) and 21% lower zinc (279 µg/g vs. 346 µg/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 µg/g vs. 0.439 µg/g; 4% higher) and selenium (1.68 µg/g vs. 1.58 µg/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively). CONCLUSIONS: There is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated.

[Low minimal stimulating current improves infraclavicular brachial plexus block efficacy].

OBJECTIVE: To investigate if low minimal stimulating current used in nerve stimulator localizing is associated with a greater likelihood of infraclavicular block success. METHODS: 188 patients, aged 14 to 64, of ASA physical status class I - II, and scheduled for surgical procedures below elbow were assigned to low current group (Group A, n = 118) or regular current group (Group B, n = 70) according to the last figure of admission number. The infraclavicular plexus block was performed using the Wilson's approach 2 cm medial and caudal to the coracoid process guided by nerve stimulator with 30 ml of 0.5% ropivacaine after eliciting distal motor responses. The minimal stimulating current (I) was adjusted to 0.1 mA < or = I < 0.3 mA in Group A or 0.3 mA < or = I < 0.5 mA in Group B. The 2 groups were further sub-divided into 2 subgroups: lateral cord subgroup when motor responses of wrist and finger-flexion and pronation of forearm were induced, and posterior subgroup when extension of wrist and finger was induced. Anesthesia efficacy was assessed 5, 10, 20 and 30 min after the local anesthetic injection. A successful blockade was defined as analgesia in all dermatomes of the five nerves (median nerve, musculocutaneous nerve, radial nerve, ulnar nerve, and medial antebrachial cutaneous nerve). RESULTS: The success rate of Group A was 84.7%, significantly higher than that of Group B (67.1%, P < 0.05). When divided into posterior and lateral cord subgroups, The success rate of the posterior subgroup of Group A was 96.5%, significantly higher than that of the posterior subgroup of Group B (78.9%, P < 0.05). CONCLUSION: Minimal stimulating current lower than 0.3 mA, significantly lower than the recommended value (0.5 mA), improves the efficacy of infraclavicular brachial plexus block, especially when the posterior cord is stimulated.