1.
Modulation of calcium oxalate monohydrate crystallization kinetics by urine of preterm neonates.
Schell-Feith, EA, Que, I, Kok, DJ, Kist-Van Holthe, JE, Kühler, E, Brand, R, Papapoulos, SE, van der Heijden, BJ
American journal of kidney diseases : the official journal of the National Kidney Foundation. 2001;(6):1229-34
Abstract
Preterm neonates frequently develop nephrocalcinosis (NC). However, the cause has not yet been elucidated. This study focuses on the effects of urine from preterm neonates on crystallization kinetics. Urine samples were collected and renal ultrasound examinations of preterm neonates (gestational age < 32 weeks) were performed during the first weeks of life, at term, and ages 6, 12, and 24 months. The effect of urine on crystallization was determined using a seeded crystal growth system, which measures the square root of solubility product ( radicalLc), percentage of growth inhibition (GI), and agglomeration inhibition ([tm]) of calcium oxalate crystals. Data for preterm neonates in the first weeks of life (n = 19) were compared with those for full-term neonates (n = 17) and healthy adults. Moreover, the correlation between [tm] and urinary (U)citrate level was studied. Mean radicalLc (0.27 +/- 0.1 versus 0.36 +/- 0.08 mmol/L) and mean [tm] (81 +/- 32 versus 143 +/- 97 minutes) were lower and mean Ucalcium-creatinine (2.20 +/- 1.74 versus 0.46 +/- 0.73 mol/mol) and Uoxalate-creatinine ratios (0.39 +/- 0.21 versus 0.16 +/- 0.09 mol/mol) were greater in preterm neonates in the first weeks of life compared with full-term neonates (p < 0.05). Furthermore, [tm] was less than the lower limit for healthy adults for all but one preterm neonate; [tm] increased and Ucalcium-creatinine and Uoxalate-creatinine ratios decreased with age (p < 0.005). There was a correlation between [tm] and citrate excretion (coefficient of 38; P < 0.001). Patients with and without NC at term did not differ statistically in mean radicalLc, percentage of GI, or [tm]. In conclusion, urine from preterm neonates in the first weeks of life is highly supersaturated and has a defective ability to inhibit calcium oxalate crystal agglomeration. This ability improves with age and is citrate mediated. We suggest that both the high level of supersaturation and defective ability to inhibit calcium oxalate crystal agglomeration contribute to the high incidence of NC.
2.
Alternating hepatic arterial infusion and systemic chemotherapy for liver metastases from colorectal cancer: a phase II trial using intermittent percutaneous hepatic arterial access.
Copur, MS, Capadano, M, Lynch, J, Goertzen, T, McCowan, T, Brand, R, Tempero, M
Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2001;(9):2404-12
Abstract
PURPOSE To evaluate the objective response to a short course of hepatic arterial infusion (HAI) using temporary, percutaneously placed catheters alternating with systemic prolonged continuous infusion fluorouracil (ci 5-FU) and daily oral leucovorin (L). PATIENTS AND METHODS Eligible patients were previously untreated (except for adjuvant therapy) adults with liver-predominant metastases, with Eastern Cooperative Oncology Group performance status of 0 to 2. Treatment regimen included HAI with fluorodeoxyuridine (FUDR) 60 mg/m2/d and L 15 mg/m2/d continuously infused daily for 4 days. After a 1-week rest, ci 5-FU was administered through a central venous access device using a dose of 180 mg/m2/d with a fixed dose of oral L at 5 mg/m2/d for 21 out of 28 days. Cycles were repeated every 6 weeks. After four cycles of therapy, patients were maintained on ci 5-FU and daily oral L until evidence of progression. RESULTS Forty-three patients were enrolled onto this trial. One patient was ineligible. The objective response rate for all patients (17 partial, zero complete) was 41% (95% confidence interval [CI], 26% to 56%). Five patients were not able to receive at least one complete cycle of HAI. Among patients who received at least one complete cycle of HAI, the response rate was 46% (95% CI, 30% to 62%). Five patients underwent a liver resection after enrolling onto the protocol. At the time of analysis, estimated median time to progression was 6 months, and estimated median overall survival was 13 months. CONCLUSION The objective response rate was comparable to that achieved with more prolonged and more frequent HAI using FUDR. This approach should be studied as an acceptable alternative to surgically placed hepatic arterial catheters/pumps and may have a role as neoadjuvant therapy for liver metastases that are unresectable, as well as an adjuvant role for patients with resected hepatic metastatic colorectal cancer.