A clinical evaluation in children of the Pharmacia ImmunoCAP system for inhalant allergens

BACKGROUND: The Pharmacia ImmunoCAP system (CAP) for assaying serum IgE specific antibodies was evaluated in a clinical setting against skin-prick test (SPT) performed using Dome/Hollister-Steir allergen extracts. The five common inhalant allergens D. pteronyssinus, D. farinae, mould mix, grass mix and cat epithelium were tested concurrently by both methods in 167 children aged 7.5-12 years. The specific SPT for D. pteronyssinus and D. farinae were also tested against the CAP house dust mite (HDM) mix. OBJECTIVE: The purpose of the study was to determine the sensitivity and specificity of the Pharmacia ImmunoCAP system for detecting serum IgE specific antibodies to inhalant allergens in a clinical setting, using SPT result as the "gold standard'. METHODS: The SPTs were performed using Dome/Hollister-Steir allergen extracts. The serum IgE specific antibodies were quantitated using the radioimmunoassay version of the Pharmacia ImmunoCAP system. A history of allergic disease was assessed using a validated questionnaire. RESULTS: SPT gave more positive reactions than CAP with the exception of cat epithelium. The concordance between SPT and CAP results was 91% over all the tests. The concordance with SPT was slightly higher for the specific CAP for D. pteronyssinus and D. farinae (93% and 95% respectively) than for the CAP HDM mix (86% and 90% respectively). There was a higher proportion of positive results for both SPT and CAP in the 115 children defined as having a history of allergic disease. Using SPT defined allergy as the gold standard, the sensitivity of the CAP system was 87% for the two specific house dust mites but was lower for cat epithelium (67%), mould mix (59%) and grass mix (46%). The sensitivity of the CAP system improved for D. pteronyssinus (96%) and the HDM mix (91%) when tested in subjects defined as having a history of allergy associated disease. The specificity of the CAP system showed less variation between allergens and ranged from 90-99%. CONCLUSION: The results of this study of children aged 7.5-12 years demonstrate that, for the inhalant allergens tested, the Pharmacia ImmunoCAP system performs well in the setting of known allergic disease.     

Quantal release at visualized terminals of a crayfish motor axon: intraterminal and regional differences

Synaptic transmission was measured at visualized terminal varicosities of the motor axon providing the sole excitatory innervation of the "opener" muscle in walking legs of crayfish (Procambarus clarkii Girard). Two questions were addressed: 1) How uniform is quantal emission at different locations along terminals innervating a single muscle fiber, and 2) can differences in quantal emission account for the different excitatory postsynaptic potential (EPSP) amplitudes generated by terminals localized in defined regions of the muscle? Extracellular "macropatch" electrodes were placed over individual varicosities, viewed after brief exposure to a fluorescent dye, and synaptic currents were recorded to determine quantal content of transmission. Along terminals supplying a single muscle fiber, nonuniform release was found: Varicosities closer to the point of origin of the terminal branch released more transmitter than those located more distally. Quantal content was higher for varicosities of the muscle's proximal region (where large EPSPs occur) than for varicosities of the central region (where small EPSPs occur). The probability of transmitter release per synapse is estimated to be greater for the proximal varicosities. At low frequencies of stimulation, quantal content per muscle fiber is two to four times larger in the proximal region. Taken in conjunction with a twofold higher mean input resistance for the proximal muscle fibers, the difference in quantal content can account for a four- to eightfold difference in EPSP amplitude. The observed mean EPSP amplitude is at least eight times larger in the proximal region. We discuss factors contributing to differences in EPSP amplitudes.     

Microdosimetric specification of the radiation quality of a d(48.5)+Be fast neutron therapy beam produced by a superconducting cyclotron

The proportional counter microdosimetric technique has been employed to quantify variations in the quality of a d(48.5)+Be fast neutron beam passing through a homogeneous water phantom. Single event spectra have been measured as a function of spatial location in the water phantom and field size. The measured spectra have been separated into component spectra corresponding to the gamma, recoil proton and alpha plus heavy recoil ion contribution to the total absorbed dose. The total absorbed dose normalized to the "monitor units" used in daily clinical use has been calculated from the measured spectra and compared to the data measured with calibrated ion chambers. The present measurements agree with the ion chamber data to within 5%. The RBE of the neutron beam is assumed to be proportional to the microdosimetric parameter y* for the dose ranges pertinent to fractionated neutron therapy. The relative variations in y*, assumed to be representative of variations in the RBE are mapped as a function of field size and spatial location in the phantom. A variation in the RBE of about 4% for points within and 8% for points outside a 10 cm x 10 cm field is observed. The variations in the RBE within the beam are caused by an increase in the gamma component with depth. An increase in the RBE of about 4% is observed with increasing field size which is attributed to a change in the neutron spectrum. Compared to the uncertainties in the prescribed dose, associated with uncertainties in the clinically used RBE, variation in the RBE between various tissues, and other dosimetric uncertainties caused by factors such as patient inhomogeneities, patient setup errors, patient motion, etc., the measured spatial RBE variations are not considered significant enough to be incorporated into the treatment planning scheme.     

Reduction mammaplasty improves symptoms of macromastia

The condition macromastia has not been defined and characterized precisely by the medical community. Whether the patient with hypertrophic breasts is a candidate for or can be helped by reduction mammaplasty is unclear to both the medical and the lay community. A prospective study of 39 women undergoing reduction mammaplasty surgery was initiated to answer these questions. Patients rated the severity of their somatic pain symptoms and discomfort before reduction mammaplasty and again after complete recovery. The severity of their symptoms and complaints was numerically graded and analyzed. These data were compared with similar data obtained from 40 "small-breasted" women of similar age. Headache, neck pain, back pain, shoulder pain, and bra strap groove pain were present in 60 to 92 percent of patients, and 97 percent of patients had at least three of these pain symptoms preoperatively. All the patients had reduction of their pain symptomatology postoperative, and 25 percent of the study patients had total elimination of pain symptoms by reduction mammaplasty. The postoperative incidence and severity of pain symptoms and discomfort complaints were statistically equivalent to or less than the levels in the control group.     

A new technique for positioning tangential fields

PURPOSE: A technique that eliminates the use of a mechanical "breast-bridge" for positioning tangential fields for treatment of the intact breast or chest wall has been developed. METHODS AND MATERIALS: Treatment set-up parameters are determined using measuring capabilities (gantry angles and source-skin distances) available on a standard simulator unit. A programmable scientific calculator is used to determine field geometry from polar coordinates for various points on the patient's skin. The calculator program determines the field size, a depth and lateral shift from a skin reference point to the isocenter for the tangential fields, and the gantry angles. The program provides additional information which facilitates the simulation process: First, the coordinates of the isocenter for the tangential fields are expressed relative to couch coordinates for an initial arbitrary isocenter so that the "auto go to" capability available on some simulators can be used. Second, the coordinates of the medial and lateral entry points can be edited when the first set of tangents are not accepted. This part of the program allows quick and efficient adjustment of the fields to obtain adequate treatment volume coverage and a minimum of irradiated lung or heart. RESULTS: Simulation of more than 300 patients has shown the technique to be a practical and efficient method for positioning tangential fields for breast or chest wall irradiation. CONCLUSION: The technique described here takes full advantage of the capabilities of the new generation of computer controlled simulators, and offers an alternative to previous methods employing a mechanical "breast-bridge."     

Habituation of the orienting response: a gating mechanism subserving selective attention

Possibilities of involution of changes in lesser circulation after closure of experimental aortopulmonary anastomosis were studied. 37 observations at various intervals after closure of anastomosis (several minutes to 13.5 months) in 25 dogs were analyzed. Before closure the anastomosis had functioned for 1-7 months. The results of histological examinations of lungs, pressure measurements in lesser circulation, heart weight, electrocardiographic and spirographic examinations were analyzed. It was found that complete involution of changes in lesser circulation was possible only in first month of existence of anastomosis, in this case with changes of both "early" and "late" types. "Late"-type changes after four months function of anastomosis had both reversible and irreversible character, whereas "early"-type changes became irreversible already after three-month duration of anastomosis. With the "late"-type changes, the operation itself (closure of anastomosis) was accompanied by symptoms of pulmonary vasomotor paresis and heart failure, whereas in the presence of "early"-type changes the operation elicited no morphological or functional changes.     

Effects of substitutions in the binding surface of an antibody on antigen affinity

The interactions between the Fab and single-chain Fv (scFv) fragments of an antibody (NC10) and its antigen, influenza virus neuraminidase, were analysed in the crystal structures of the Fab-neuraminidase and scFv-neuraminidase complexes. To investigate the contribution to binding made by cavities, salt links and hydrogen bonds in the antibody- antigen interface, 14 single amino acid replacements were made at six contact residues in the scFv fragment by site-directed mutagenesis. The binding affinity of each mutant scFv antibody for neuraminidase was determined with a BIAcore optical biosensor. Four of the mutations resulted in large changes in the free energy of binding to neuraminidase (deltadeltaG > 1 kcal/mol) and together may account for approximately 70% of the free energy of binding. Hence these data support the theory that a small number of residues form the 'functional epitope' and are most important for binding of NC10 to neuraminidase. The salt link between antibody residue (Asp)H56 and (Lys)N432 from neuraminidase was demonstrated to be important for affinity, since substitution of (Asp)H56 with Asn caused a large reduction in the free energy of binding (deltadeltaG = +2.8 kcal/mol). Hydrogen bonds provided by (Tyr)L32 and (Asp)H56 were also important for binding: mutation of (Tyr)L32 to Phe resulted in a significant reduction in binding affinity (deltadeltaG = +1.7 kcal/mol). Disruption of hydrophobic interactions (van der Waals contacts) led to significant reductions in affinity also ((Tyr)H99 to Ala, deltadeltaG = +1.5 kcal/mol; (Leu)L94 to Ala, deltadeltaG > +3.0 kcal/mol). An attempt to increase binding affinity by filling a cavity in the interface with a larger antibody side chain was unsuccessful, as the free energy gained by new antibody-antigen interactions did not compensate for the removal of cavity-bound water molecules.      

Role of active site tyrosine residues in catalysis by human glutathione reductase

Tyr114 and Tyr197 are highly conserved residues in the active site of human glutathione reductase, Tyr114 in the glutathione disulfide (GSSG) binding site and Tyr197 in the NADPH site. Mutation of either residue has profound effects on catalysis. Y197S and Y114L have 17% and 14% the activity of the wild-type enzyme, respectively. Mutation of Tyr197, in the NADPH site, leads to a decrease in Km for GSSG, and mutation of Tyr114, in the GSSG site, leads to a decrease in Km for NADPH. This behavior is predicted for enzymes operating by a ping-pong mechanism where both half-reactions partially limit turnover. Titration of the wild-type enzyme or Y114L with NADPH proceeds in two phases, Eox to EH2 and EH2 to EH2-NADPH. In contrast, Y197S reacts monophasically, showing that excess NADPH fails to enhance the absorbance of the thiolate-FAD charge-transfer complex, the predominant EH2 form of glutathione reductase. The reductive half-reactions of the wild-type enzyme and of Y114L are similar; FAD reduction is fast (approximately 500 s-1 at 4 degreesC) and thiolate-FAD charge-transfer complex formation has a rate of 100 s-1. In Y197S, these rates are only 78 and 5 s-1, respectively. The oxidative half-reaction, the rate of reoxidation of EH2 by GSSG, of the wild-type enzyme is approximately 4-fold faster than that of Y114L. These results are consistent with Tyr197 serving as a gate in the binding of NADPH, and they indicate that Tyr114 assists the acid catalyst His467'.     

Periodontal considerations in an overdenture population

Three variable microsatellite loci have been isolated from the American lobster, Homarus americanus. In a population sample from the Gulf of Maine, the effective numbers of alleles (Ne) for the two most variable loci were 16.33 and 13.19, respectively. Reduced variability at all three loci was seen in the European lobster, H. gammarus, for which the maximum Ne was 4.00. The reduction in variability in H. gammarus is consistent with a bottleneck event. Inheritance analysis using H. americanus demonstrated segregation of codominant alleles and the absence of linkage. Null alleles were observed at two loci in inheritance studies. This study demonstrates that microsatellite loci should be useful in studying the population structure of clawed lobsters.