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Biomedical subjects

C C Peck

Publications and source records attributed to C C Peck.

At least 91 records · Page 5Linked to original sources
PubMed1975

Determinants of the renal clearance of digoxin.

The renal clearances of digoxin, creatinine, and urea nitrogen were determined simultaneously in each of 41 patients receiving digoxin, in most of whom there was prerenal azotemia. Mean plus or minus SD values were: blood urea nitrogen (BUN), 26.1 plus or minus 12.8 mg per 100 ml; creatine, 1.1 + 0.41 mg per 100 ml; creatinine clearance, 78 plus or minus 42 ml/min/1.73 m2; digoxin clearance, 66.6 plus or minus 42.1 ml/min/1.73 m2; urea nitrogen clearance, 27.8 plus or minus 19.2 ml/min/1.73 m2. Correlation analysis revealed that urea clearance is superior to creatinine clearance, and BUN is superior to serum creatinine concentration in the degree of relationship to renal digoxin clearance. Moreover, using partial correlation techniques, it is apparent that in these patinets digoxin clearance was significantly related to urine flow rate. These findings are compatible with the hypothesis that digoxin undergoes some degree of tubular reabsorption as well as filtration and secretion.

Adult↗
PubMed1975

Pharmacokinetic rationale for a malarial suppressant administered once monthly.

Serum was collected from six adults participating in a field trial of sulfadoxine and pyrimethamine in combination which was being administered once monthly for malaria suppression. Samples were drawn during each of two consecutive months three hours, and 7, 14 and 28 days following a dose of 1 500 mg sulfadoxine. Serum sulfadoxine concentration was measured using the method of Bratton and Marshall (1939). Initial serum concentrations averaged 19-9 plus or minus 2-4 (SD) mg/100 ml and decayed to 6-2 plus or minus 2-8 mg/100 ml at 14 days. Serum sulfadoxine concentrations were still detectable at 28 days following a dose (2-1 plus or minus 1-5 mg/100 ml). Elimination half-time averaged 195 plus or minus 44 hours. The presistent serum concentrations of sulfadoxine following monthly doses documented here during field-use of this drug are in agreement with the successful clinical results reported for such a regimen (Lewis and Ponnampalam, 1974; O'Holohan and Hugoe-Mathews, 1971; Wolfensberger, 1971).

Adolescent↗
PubMedDate not supplied

The in vivo survival of red blood cells stored in modified CPD with adenine: report of a multi-institutional cooperative effort.

In order to provide data in support of licensure applications for citrate-phosphate-dextrose (CPD) supplemented with adenine, a multi-institutional cooperative effort was organized to determine survivability of red blood cells subjected to prolonged liquid storage. Two manufacturers supplied plastic multiple bag blood storage containers prefilled with modified CPD (glucose 25% greater than the normal concentration) supplemented with adenine (17.0 to 17.3 mg per 63 ml of anticoagulant; 0.25 millimolar approximate final concentration when diluted with 450 ml of whole blood for 35 days showed a mean survival of 80.53 +/- 6.44 per cent (1 SD). Both red blood cell and supernatant plasma biochemical characteristics were comparable to those reported for whole blood stored for 21 days in either acid-citrate-dextrose (ACD) or CPD. Red blood cells from 19 units stored as concentrates for 35 days (Hct 75.03 +/- 3.74%) had a mean survival of 71.38 +/- 10.3 per cent with considerable interdonor variation in survival and interlaboratory variation in some biochemical characteristics. Red blood cells from eight units stored as concentrates (Hct 75.38 +/- 4.30%) for 28 days showed a mean survival of 83.97 +/- 6.10 per cent and biochemical characteristics comparable to those reported for red blood cell concentrates stored in CPD or ACD for 21 days. Modified CPD with adenine as formulated offers an improved anticoagulant for blood banking by extending the permissible red blood cell storage period.

Adenine↗
PubMedDate not supplied

Enhanced solubility of 2,8 dihydroxyadenine (DOA) in human urine.

Water solubility of the adenine catabolite 2,8 dihydroxyadenine (DOA) frequently forms the basis for predicting potential DOA crystal formation in human urine following infusion of adenine-fortified blood. Measurements relevant to solubility, ionic dissociation, and supersaturability of DOA in aqueous buffers and human urine at 37 C establish striking quantitative differences in the physico-chemical behavior of DOA in the two media. The basal solubility of DOA is 1.53 +/- 0.04 mg/1 (approximately 9 X 10(-6) M) in water (pH 6.5). DOA is an ampholyte characterized by aqueous thermodynamic macrodissociation constants of pKa1 = 2.6, pKa2 = 8.1, and pKa3 = 11.52. This compound displays pH-dependent solubility, although significant solubility increases beyond basal values do not occur within the physiologic pH range for human urine. Supersaturated aqueous solutions (three to sixteen times basal solubility) can be achieved but are unstable. In contrast, human urine at 37 C exhibits enhanced capacity for solubilizing DOA. In vitro basal solubility is 2.68 +/- 0.84 mg/1 at pH 5.0 and 4.97 +/- 1.49 mg/1 at pH 7.8. The apparent pK 2for DOA in urine of 7.9 to 8.1 is dependent upon urine osmolality. Urine can be supersaturated with Doa in vitro to approximately ten times its basal solubility by adding DOA solubilized in weak base, or by evaporation of a urine-DOA mixture. DOA remains supersaturated in urine for at least 16 hours despite gentle agitation. Little variation in in vitro DOA apparent supersaturation was found among urine samples from four normal individuals (40.38 +/- 3.33 mg/1). A patient receiving oral adenine exhibited urinary DOA solubility in considerable excess (96.0 mg/1) of that predicted from water and from in vitro urine solubility studies. Thus, water solubility of DOA is poorly predictive of in vitro and in vivo DOA solubility in human urine. On the basis of these data, estimates of the load of adenine-fortified blood expected to result in urinary DOA crystal formation may be revised upward.

Adenine↗
PubMedDate not supplied

DEHP in blood.

Explore the source record for details and available documents.

Diethylhexyl Phthalate↗
PubMedDate not supplied

Di-2-ethylhexyl phthalate (DEHP) and mono-2-ethylhexyl phthalate (MEHP) accumulation in whole blood and red cell concentrates.

Plasma DEHP concentrations were measured weekly in whole blood and red cell concentrates (RCC) during 21 days of storage in standard CPD within PL-130 blood bags. In addition, DEHP and MEHP accumulation patterns were investigated in blood stored for 42 days in modified CPD with adenine within PL-146 and BB-69 storage containers. Total per-unit plasma DEHP of RCC units was 49 to 71 per cent of the total in plasma of whole blood units (PL-130). From 28 to 42 days, mean DEHP levels were 12 to 19 per cent higher in whole blood stored in PL-146 than in BB-69. Although MEHP was not found in any blood bag plastic, MEHP accumulated in plasma during whole blood storage. MEHP concentrations were 2.8 to 3.8 times higher in plasma stored in BB-69 than in PL-146. It is postulated that MEHP arises from hydrolysis of DEHP by plasma lipase, even in frozen plasma sample, and that the rate of this reaction is influenced by blood bag plastic surface characteristics.

Blood Preservation↗
PubMedDate not supplied

In vitro evaluation of platelets stored in CDP-adenine formulations.

Little information is available about the effect of adenine and added glucose on stored platelets. Two new formulations, CPDA-2 and CPDA-3, contain 34 mg adenine per 63 ml preservative and extra glucose (1.75 and 2.0 times the glucose in standard CPD). We have studied the in vitro integrity of platelet concentrates stored in CPD, CPDA-1, CPDA-2, and CPDA-3 at 22 C for 72 hours. Morphology score, pH, platelet size, population distribution parameters, and electron microscopic ultrastructure did not show any adverse effects which could be ascribed to the presence of adenine or extra glucose or both. No differences in platelet adenosine triphosphate (ATP) concentration or plasma glucose utilization during storage were found between CPD and CPDA-1 platelets. The results suggest that adenine and added glucose in these preservatives are not detrimental to platelets in vitro by the measures employed.

Adenine↗
PubMedDate not supplied

The in vitro evaluation of modifications in CPD-adenine anticoagulated-preserved blood at various hematocrits.

Erythrocytes stored in the new CPD-adenine anticoagulant (CPDA-1) barely met the 70 per cent 24-hour postinfusion 51Cr recoveries on day 35 when stored at hematocrit greater than or equal to 75 per cent. CPDA-1 differs from CPD in that it has 1.25 times the glucose concentration plus 17.3 mg adenine/63 ml. In an effort to improve the survivability (or viability) of red blood cells following extended storage (35+ days), two new CPD-adenine anticoagulants have been tested in vitro. CPDA-2 and CPDA-3 (both of which contain 34.6 mg/63 ml of anticoagulant or 0.50 mM adenine [final blood concentration], and either 1.75 times or 2.0 times respectively the amount of glucose used in CPD) have been tested for whole blood or red blood cell storage to 42 days. Red blood cell ATP concentrations were better maintained throughout 42 days of storage in both of these formulations than in CPDA-1 at hematocrits that ranged from 40 to 85. Other biochemical parameters (2,3-DPG, pH, plasma hemoglobin) were similar to those of blood stored in CPD or CPDA-1.

Adenine↗
PubMedDate not supplied

Some properties of blood stored in anticoagulant CPDA-1 solution. A brief summary.

Approval of the new anticoagulant preservative, CPDA-1, was based in part on data from human clinical trials of CPDA-1 performed by six cooperating laboratories and two blood bag manufacturers. Biochemical and red blood cell survival properties of 123 units of blood stored for 28 to 35 days in CPDA-1 (as reported by cooperating laboratories) are briefly summarized.

Adenine↗
PubMedDate not supplied

Effect of heat on the conversion of di-2-ethylhexyl phthalate to mono-2-ethylhexyl phthalate in human plasma.

Plasma di-2-ethylhexyl phthalate (DEHP), which accumulates during blood storage in plastic bags, gives rise to plasma mono-2-ethylhexyl phthalate (MEHP). This also in plasma samples awaiting analysis, which are no longer stored in plastic bags. Heating plasma samples at 60 C for 25 to 30 minutes in a water bath effectively halts conversion of DEHP to MEHP during subsequent room temperature storage for at least 100 hours. This result is consistent with the view that MEHP accumulation in plasma is due to enzymatic hydrolysis of DEHP by esterase (s) which can be heat-inactivated.

Blood Preservation↗
PubMedDate not supplied

In vivo viability of red blood cells stored in CPDA-2.

The marginal viability of erythrocytes stored for 35 days as red blood cell concentrates in citrate-phosphate-dextrose-adenine-one (CPDA-1) was attributed to inadequate nutrient support with adenine and glucose. In an effort to improve the viability of red blood cells following extended storage, a new CPD-adenine and 1.4 times more glucose than CPDA-1. The efficacy of CPDA-2 was evaluated in vivo by measurement of 24-hour postinfusion recovery of 51Cr-labeled erythrocytes which had been stored as whole blood or red blood cell concentrates for 5 to 8 weeks. All red blood cell concentrates, and the whole blood units stored for 35 and 42 days, were held at room temperature for 8 hours prior to processing and/or refrigeration. CPDA-2 yielded significantly higher 51Cr survivals than CPDA-1 and exceeded the accepted criterion for anticoagulant preservative efficacy of 70 percent postinfusion survival of red blood cells after storage for a period of 42 days. Preliminary data supports possible usage to 49 days. Plasma glucose and red blood cell ATP concentration were maintained better in CPDA-2 than in CPDA-1. When compared to historical controls for CPD and CPDA-1 the data suggest that red blood cells stored in CPDA-02 will have superior viability throughout the entire storage period. CPDA-2 is a candidate to replace CPDA-1 as the anticoagulant-preservative solution of choice for red blood cell concentrates.

Adenine↗
PubMedDate not supplied

Implant angulation: a measurement technique, implant overdenture maintenance, and the influence of surgical experience.

PURPOSE: The purposes of this study were to develop a technique to measure the angulation between two implants and between each implant and reference planes, to analyze the relationship between the maintenance (adjustments and repairs) of ball-attachment mandibular implant overdentures and implant angulation, and to see if there is any correlation between surgeon experience and implant orientation. MATERIALS AND METHODS: Final casts of 41 patients who had received two-implant ball-attachment mandibular overdentures were used to measure implant angulations using digital photographs and plane geometry. The measured angles were compared with the number of adjustments and repairs of the prostheses and analyzed by surgeon experience for any trends. RESULTS: No significant relationships were found between number of adjustments and repairs and the interimplant angles. However, there was a significantly higher number of repairs when the lingual inclination of an implant was > or = 6.0 degrees (P = .033) or if the facial inclination was < 6.5 degrees (P = .036). Less experienced surgeons had a significantly greater tendency to place implants that diverged from each other in the frontal plane (P = .045) and with a facial or lingual inclination in the sagittal plane (P = .035). CONCLUSION: While interimplant angulation did not appear to affect prosthesis maintenance, individual implants with a lingual inclination > or = 6 degrees and a facial inclination < 6.5 degrees were associated with significantly more prosthesis repairs. There was a tendency for implants placed by less experienced surgeons to demonstrate greater inclination.

Adult↗
PubMedDate not supplied

Pharmacokinetics of intravenous immunoglobulin (Sandoglobulin) in neonates.

Sandoglobulin administration to neonates was safe at a dose of 500 mg/kg. GBS-specific IgG was significantly elevated for 14 days postinfusion. Pharmacokinetic studies suggest a two-compartment model with a redistribution phase and terminal elimination phase. A half-life of 11.3 days for the initial phase and 30.7 days for the terminal phase was observed. Further, studies will be necessary to determine if IGIV therapy will be effective in preventing or treating GBS infections in neonates.

Antibodies, Bacterial↗