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Biomedical subjects

D T Casto

Publications and source records attributed to D T Casto.

27 records · Page 2Linked to original sources
PubMed1988

Lack of endogenous crossreactivity with three digitoxin radioimmunoassays in adults with renal insufficiency.

The possibility of interference by apparent digitoxin-like immunoreactive substance (DTLIS) with three radioimmunoassays was studied in patients with renal insufficiency. From each of 25 adult patients with renal insufficiency and 25 age-matched and sex-matched control subjects with normal renal function, a single serum sample was obtained and assayed for digitoxin content by three commercially available radioimmunoassays (GammaCoat, Coat-A-Count, and the Wien assay). Although two of the three assays found measurable concentrations, the difference in apparent digitoxin concentrations between the control subjects and those with renal insufficiency was not significant. Assay interference could not be explained on the basis of differences in age, serum creatinine concentration, or weight. The magnitude of DTLIS interference in relation to the digitoxin therapeutic range appears to be small with the radioimmunoassays used in this study.

Acute Kidney Injury↗
PubMed1985

Carbamazepine and carbamazepine-epoxide serum protein binding in newborn infants.

To evaluate the serum protein binding of carbamazepine (CBZ) and its active metabolite carbamazepine-10, 11-epoxide (CBZ-E) in newborns, cord serum was obtained from 20 infants at the time of birth. Each of the samples was spiked to concentrations of CBZ 12 + CBZ-E 3 micrograms/ml, and CBZ 4 + CBZ-E 1 micrograms/ml and then subjected to analysis for total and free drug concentrations. Total drug concentrations were determined by high pressure liquid chromatography (HPLC), and free drug concentrations were determined by ultrafiltration and subsequent HPLC. The mean percentage of CBZ unbound, calculated as (free drug concentration divided by total drug concentration) X 100, was 30.6 and 29.8% at the high and low concentrations, respectively. Results for CBZ-E were 52.0 and 47.5% at the high and low concentrations, respectively. Compared with previously published values for protein binding in older children and adults, neonates appear to bind CBZ to a lesser degree and CBZ-E to the same degree. The lower binding of CBZ suggests that the therapeutic range of total CBZ in neonates may differ from that in older patients; however, this will have to be determined through clinical study. As previously demonstrated in older patients, CBZ and CBZ-E binding was variable. Monitoring of free CBZ serum concentrations in neonates appears advisable because of this variability.

Blood Proteins↗
PubMed1982

Urine and plasma free phenytoin concentration correlation.

In an attempt to find a simple, noninvasive method for estimating the plasma free concentration (CPf) of phenytoin (PHT), the relationship between urine PHT concentration (Cu) and CPf was studied in 40 epileptic patients who were 6 to 50 yr old. Cu was determined by gas-liquid chromatography and CPf by equilibrium dialysis at 37 degrees. Cu was generally greater than CPf, but correlation between the two was strong (r2 = 0.876) and in the same range as previously published results for saliva and CPf. Correlation of Cu with CPf was not influenced by patient age, urine pH, or urine flow rate. In 24 patients timed urine collections were obtained and calculated renal clearances of PHT were shown to increase in proportion to urine flow rates. Although it is not known if renal impairment and albuminuria will alter the relationship between Cu and CPf it appears that Cu may be useful in estimating the concentration of pharmacologically active PHT in plasma.

Adolescent↗
PubMedDate not supplied

Prevention of group B Streptococcus infection in neonates.

OBJECTIVE: To review the epidemiology of group B Streptococcus (GBS) infection, risk factors for infection, and clinical manifestations of disease in the neonate, as well as the role of chemoprophylaxis and immunoprophylaxis in prevention of GBS disease and current recommendations for prevention. DATA SOURCES AND STUDY SELECTION: MEDLINE searchers (1976-1997) of the English-language literature. DATA SYNTHESIS: Despite clinical advances in health care in the past two decades, GBS remains a leading cause of serious neonatal infection. Most early-onset GBS infections can be prevented through the use of intrapartum antimicrobial chemoprophylaxis. Preventing GBS infection in neonates is more cost-effective than treating GBS infections, and implementing prevention programs can reduce morbidity and mortality resulting from GBS disease. Many proposals have been made regarding prevention strategies; however, they have not been implemented widely and consistently in the US. To coordinate both pediatric and obstetric supported strategies, the Centers for Disease Control and Prevention (CDC) recently published recommendations for prevention of neonatal GBS disease through two possible strategies. In the first strategy, intrapartum antibiotic chemoprophylaxis should be offered to all women identified by prenatal culture as colonized and those who develop premature membrane rupture or onset of labor at less than 37 weeks gestation. The second strategy involves administration of intrapartum antibiotics to all women who develop one or more risk factors at the time of membrane rupture or onset of labor. CONCLUSIONS: GBS is difficult to eradicate, causing many women to be colonized with the organism during pregnancy and labor, thereby infecting their infant. Prevention strategies have been published for more than 10 years without successful implementation. Although optimal prevention management has not been defined, following one of two strategies recommended by the CDC can prevent the majority of GBS infections in neonates.

Antibiotic Prophylaxis↗
PubMedDate not supplied

Preventing Haemophilus influenzae type b disease.

The pathogenesis of Haemophilus influenzae type b (Hib) disease and methods for limiting spread of outbreaks of Hib disease are reviewed. Many strains of H. influenzae are surrounded by an outer polysaccharide capsule; of the six antigenically distinct capsular types, Hib is the predominant cause of such serious infections as meningitis, especially among children younger than five years of age. The age-specific incidence of Hib disease appears to be related to the relatively small concentrations of anti-Hib antibody present in young children. Children younger than 48 months of age who reside in the same house or attend the same day-care center as a child who develops Hib disease appear to be at increased risk for contracting systemic Hib infections. Prophylactic administration of rifampin 20 mg/kg once daily for four days can substantially decrease asymptomatic carriage of Hib in household contacts of the index patient and reduce the incidence of secondary Hib disease. The index patient should also receive prophylactic rifampin therapy before discharge from the hospital; i.v. antibiotics may cure the systemic infection but allow nasopharyngeal colonization to persist. A vaccine formulated from purified Hib capsular polysaccharide confers protection to more than 90% of children vaccinated at a minimum age of 24 months. Other candidates for vaccination include children between the ages of two and five years who attend day-care centers and children with anatomic or functional asplenia or malignancies. The vaccine is not effective in children younger than 18 months of age (who account for 60% of Hib disease in the U.S.); methods to increase vaccine immunogenicity in young infants are being evaluated. Reduction of Hib disease in the U.S. may be possible through widespread use of the new vaccine.

Adolescent↗