Comparing inhaled ultrafine versus fine zinc oxide particles in healthy adults: a human inhalation study

RATIONALE: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 microm diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1-1.0 microm diameter). OBJECTIVES: We compared exposure-response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. METHODS: In a human inhalation study, 12 healthy adults inhaled 500 microg/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. MEASUREMENTS AND MAIN RESULTS: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. CONCLUSIONS: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 microg/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints.     

Chronic resistance exercise training improves natural killer cell activity in older women

BACKGROUND: Regular exercise has been reported to slow the age-associated declines in natural killer cell activity (NKCA). To evaluate this response, we recruited older, postmenopausal women (65-85 years old) to fill one of two groups: training (10 weeks of resistance exercise; TR) or control. METHODS: Blood samples were collected from an arm vein in the TR group at rest (PRE), immediately following (POST), and 2 hours (2H) following an acute bout of resistance exercise both before (BEFORE) and after (AFTER) training. Leukocytes and NKCA were determined by flow cytometry and a whole blood (51)Cr release assay, respectively. RESULTS: Acute exercise increased total leukocyte (p < .05), CD8 (p < .05), CD4 (p < .05), and CD56 counts (p < .05), but there was no effect of training. NKCA was greater TR-AFTER-PRE (136%), -POST (80%), and -2H (127%) compared to similar values from TR-BEFORE (p < .05). CONCLUSION: Increased resting NKCA after chronic resistance training suggests that immunity has been improved.     

Left renal venous hypertension “nutcracker” syndrome: Managed by Direct Renocaval Reimplantation

Since 1978 a diagnosis of left renal venous hypertension has been established in 3 patients. All 3 had otherwise unexplained left flank and abdominal pain, 2 had left renal gross hematuria, and 2 were found to have ureteral and peripelvic varices demonstrated by selective renal venography. All were found to have mild to moderate pressure gradients between the left renal vein and vena cava, presumably due to compression of the left renal vein between the aorta and overlying superior mesenteric artery. Direct left renocaval reimplantation was performed in all cases, with resection of the collateral varices that were present in 2 cases. Severe unrelenting pain was the primary indication for surgery in all cases, rather than hematuria. All remain asymptomatic one to four years after surgery.