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P Shackelford

Publications and source records attributed to P Shackelford.

6 recordsLinked to original sources
PubMed1986

Human IgG subclass assays using a novel assay method.

To facilitate assays for human IgG subclasses, we have adapted a novel assay method (particle concentration fluorescence immunoassay) (Jolley et al., 1984; MacCrindle et al., 1985) using one polyclonal and several monoclonal antibodies for human IgG subclasses. The advantages of this new assay over previously described methods are sensitivity (0.3-3 micrograms/ml), and automated measurement of multiple samples in a short time (2 h). We found that a monkey antibody for IgG2 and monoclonal antibodies for IgG1, IgG4b epitope, and IgG3 can be adapted to this method. We evaluated 7 different antibodies to IgG4 without finding a suitable monoclonal antibody for this assay method. Several of these IgG4 hybridoma antibodies, however, could be used in a competitive radioimmunoassay using polyvinyl microtiter plates. The usefulness of a monoclonal antibody to the IgG4b epitope was evaluated because no suitable monoclonal antibodies for IgG2 are available. Because IgG4 levels are usually much smaller than IgG2 levels, and the IgG4b epitope is expressed on all IgG2 alleles and only some IgG4 alleles (Kunkel et al., 1970), the antibody for IgG4b is potentially useful to screen a large number of samples for IgG2 deficiency. However, when the monoclonal antibody for IgG4b was compared with an IgG2 specific antibody produced in a monkey, the IgG4b antibody could identify only about half of the patients with known IgG2 deficiency.

Antibodies, Monoclonal↗
PubMed1985

Hypothesis: neonatal necrotizing enterocolitis is caused by the acquisition of a pathogenic organism by a susceptible host infant.

The following hypothesis is offered for the etiology of neonatal necrotizing enterocolitis (NEC): that NEC is caused by the acquisition of a potentially pathogenic organism by a susceptible host infant. To test this hypothesis, serum IgM, IgG, IgA, C3, and C4, were measured in 11 neonates with NEC and 11 control infants matched for age and birth weight. Mean initial serum IgA was found to be significantly greater (p less than 0.05) in patients with NEC (8.4 mg/dl) than in control subjects (0.6 mg/dl). This difference persisted during a subsequent period of observation. There were no significant differences in initial concentrations of the other immunoglobulins or complement components. Serum IgM was noted to increase and serum IgG to decrease in both study groups during the period of observation. C3 rose minimally and C4 fell in patients with NEC. An explanation for this alteration in serum IgA concentration in infants with NEC is, at this time, speculative. However, this association, suggests that further evaluation of host susceptibility in this patient group may lead to a better understanding of this disorder.

Complement C3↗
PubMed1984

Pharmacokinetics of clindamycin phosphate in the first year of life.

The pharmacokinetics of intravenously administered clindamycin phosphate was studied in 40 children less than 1 year of age. Mean peak serum concentrations were 10.92 micrograms/ml in premature infants less than 4 weeks of age, 10.45 micrograms/ml in term infants greater than 4 weeks, and 12.69 micrograms/ml in term infants less than 4 weeks of age. Mean trough concentrations were 5.52, 2.8, and 3.03 micrograms/ml, respectively, in the same groups. Serum half-life was significantly longer (8.68 vs 3.60 hours) in premature compared with term infants less than 4 weeks of age. Both premature and term infants less than 4 weeks had significantly decreased clearance when compared with infants greater than 4 weeks (0.294 and 0.678, respectively, vs 1.58 L/hr). Clearance was significantly greater (1.919 vs 0.310 L/hr) and serum half-life less (1.75 vs 7.57 hours) in infants with body weight greater than 3.5 kg. On the basis of these data it is recommended that in infants greater than 4 weeks or greater than 3.5 kg, intravenous clindamycin dosage be 20 mg/kg/day in four divided doses. In premature neonates less than 4 weeks, the dose should be reduced to 15 mg/kg/day in three divided doses. Term infants greater than 1 week of age may also receive 20 mg/kg/day in four doses.

Clindamycin↗
PubMed1979

Epidemiologic and bacteriologic evaluation of neonatal necrotizing enterocolitis.

The incidence of necrotizing enterocolitis (NEC) in our neonatal unit has varied from 4.7% to zero to 4.4% during three time periods. Simultaneously, significant changes have occurred in the spectrum of bacterial species in the gastrointestinal tract of unaffected infants in the same unit. During the first period of increased attack rate, 82% of gastric and 88% of fecal Enterobacteriaceae were E. coli and K. pneumoniae. When the attack rate decreased the frequencies were 11% (gastric) and 47% (fecal), and P. mirabilis was retrieved with increased frequency. The return of E. coli and K. pneumoniae as the dominant organisms was associated with an increase in NEC. Infants with NEC, compared with controls, had a statistically significant increased frequency of retrieval of E. coli and K. pneumoniae from gastric and fecal samplings. The data suggest an active role for certain enteric bacteria in the pathogenesis of NEC.

Enterocolitis, Pseudomembranous↗
PubMedDate not supplied

Multiple myeloma.

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Bone Neoplasms↗