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Richard T Blaszak

Publications and source records attributed to Richard T Blaszak.

6 recordsLinked to original sources
PubMed2006

Disposition of ceftazidime after intraperitoneal administration in adolescent patients receiving continuous cycling peritoneal dialysis.

BACKGROUND: Peritonitis is the single most common complication in children maintained on continuous cycling peritoneal dialysis (CCPD) and a significant cause of morbidity. Recent consensus guidelines for the treatment of peritonitis in children receiving peritoneal dialysis recommend the combined intraperitoneal administration of ceftazidime with either a first-generation cephalosporin or vancomycin. The objective of this study is to determine whether a continuous maintenance dose of intraperitoneal ceftazidime in the absence of a loading dose would maintain adequate serum and dialysate concentrations to be effective in the treatment of peritonitis. METHODS: Five ambulatory patients on CCPD therapy were studied with continuous intraperitoneal administration of ceftazidime (125 mg/L). Blood, dialysate, and urine samples were collected at specified intervals during a 24-hour period. Ceftazidime concentrations were measured by using a high-performance liquid chromatography assay. RESULTS: Mean serum concentrations at completion of the short rapid cycles and at 24 hours were 28.92 +/- 13.64 and 23.92 +/- 11.93 microg/mL, respectively. Serum bioavailability at 24 hours was 74% +/- 6%. Mean dialysate concentrations at completion of the short rapid cycles and at 24 hours were 87.43 +/- 19.18 and 32.06 +/- 6.27 microg/mL, respectively. All 5 patients achieved serum and dialysate ceftazidime concentrations greater than the mean inhibitory concentration within 4 hours. CONCLUSION: In adolescent patients on CCPD therapy, a continuous maintenance dose of intraperitoneal ceftazidime in the absence of a loading dose achieves serum and dialysate levels greater than the mean inhibitory concentration of sensitive organisms within 4 hours that persist for 24 hours.

Adolescent↗
PubMed2005

Hyperphosphatemia in children receiving peritoneal dialysis--an educational program.

Hyperphosphatemia has been associated with the development of secondary hyperparathyroidism, renal osteodystrophy, cardiovascular calcification and increased risk of death. Using a one group, pretest-posttest study design, we sought to evaluate changes in serum phosphorus, calcium, parathyroid hormone and subject knowledge in response to a 3-month educational intervention. Mean serum phosphorus levels did not differ significantly between the three evaluation periods: pretreatment (5.69 mg/dl), treatment (5.84 mg/dl) and posttreatment (6.17 mg/dl). Mean serum calcium, calcium-phosphorus product and PTH values also did not differ significantly between the treatment periods. We observed no difference between the subject test scores between the two testing periods. Calcium-phosphorus product, serum phosphorus and PTH values on average, despite the education program, remained outside the K/DOQI target guidelines 44, 56 and 81% of the time, respectively. The results of this study suggest that an aggressive 3-month patient education program targeting dietary phosphorus knowledge, phosphate binder name and dosing, and knowledge of medical consequences associated with non-compliance had no effect on the serum phosphorus, calcium, PTH or phosphate binder need.

Adolescent↗
PubMed2005

Adequacy of peritoneal dialysis in children following cardiopulmonary bypass surgery.

Acute renal failure requiring renal replacement therapy can complicate cardiopulmonary bypass in children. Peritoneal dialysis has been shown to stabilize electrolytes and improve fluid status in these patients. To assess dialysis adequacy in this setting, we prospectively measured Kt/V and creatinine clearance in five patients (6-839 days of age) requiring renal replacement therapy at our institution. Median dialysis creatinine clearance was 74.25 L/week/1.73m(2) (range 28.28-96.63 L/week/1.73m(2)). Residual renal function provided additional solute clearance as total creatinine clearance was 215.97 L/week/1.73m(2) (range 108.04-323.25 L/week/1.73m(2)). Dialysis Kt/V of >2.1 (median 4.84 [range 2.12-5.59]) was achieved in all patients. No dialysis-associated complications were observed. We conclude that peritoneal dialysis is a safe, simple method of providing adequate clearance in children who develop acute renal failure following exposure to cardiopulmonary bypass.

Acute Kidney Injury↗
PubMed2004

PKD1 intron 21: triplex DNA formation and effect on replication.

Although autosomal dominant polycystic kidney disease is transmitted in an autosomal dominant fashion, there is evidence that the pathophysiology of cystogenesis involves a second hit somatic mutation superimposed upon the inherited germline mutation within the renal tubule cells. The polypurine.polypyrimidine (Pu.Py) tract of PKD1 intron 21 may play a role in promoting somatic mutations. To better characterize this tract and to evaluate its potential to participate in mutagenesis, we investigated the thermodynamics of intramolecular triplex formation by 15 Pu.Py mirror repeat tracts from PKD1 intron 21 by 2D gel electrophoresis. We demonstrate that intramolecular triplexes form with modest superhelical tensions for all the tracts examined. Primer extension studies demonstrated significant polymerase arrest within the Pu.Py tracts in one direction of replication only. We found correlation between polymerization arrest and both the potential length of the triplex and superhelical tension of intramolecular triplex formation. The presence of a Pu.Py tract also led to a replication blockade and double-strand breakage using an SV40 in vitro replication assay with HeLa cell extracts. During DNA replication, the G-rich template of the PKD1 Pu.Py tracts may form a triplex structure with the nascent strand, thereby blocking replication and potentially leading to recombination and mutation.

DNA↗
PubMed2003

Use of appendix for complete transplant ureteral necrosis.

A 3-yr-old boy with posterior urethral valves underwent cadaveric renal transplant. On the ninth day after transplantation the patient developed a urinary leak, with complete ureteral necrosis. There was insufficient length of undamaged ureter to permit ureteroneocystostomy, unavailability of a native ureter to permit ureteroureterostomy, and an inability to mobilize the transplant kidney or bladder sufficiently to permit direct pyelovesicostomy. As the kidney was otherwise functioning perfectly, we decided to create an appendiceal conduit in the hope of salvaging the patient's renal allograft. At present, 7 months post-transplant, the child is clinically well with a serum creatinine of 0.7 mg/dL. Complete ureteral necrosis is an infrequent but devastating complication following renal transplantation. We report a novel method that allowed an otherwise normally functioning cadaveric graft to be salvaged.

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