Binding kinetics of monoclonal antibody using antigen-beta-galactosidase hybrid protein: application to measurement of peptide antigenicity

A simple method for determination of binding kinetics of a solid-phase antibody using antigen-beta-galactosidase hybrid protein was evaluated. To minimize conformational change of the antigen binding site of the antibody when directly binding to a microtiter plate, the microtiter plate was precoated with protein A. The binding and free antigen concentrations were directly obtained from the beta-galactosidase activity. This method can be used for analyses of the equilibrium dissociation constant (KD), and the association (Kass) and dissociation (Kdiss) rate constants. Peptide antigenicity was also analyzed by competitive ELISA using this method. Since both antigen-beta-galactosidase and the peptide used are localized in the fluid-phase, the proper affinity constant (KA) of the peptide can be estimated from the KD value of the antigen-beta-galactosidase-antibody interaction, and from the IC50 value of the peptide.     

Sodium, potassium-activated adenosine triphosphatase activity is impaired in the guinea pig pancreatic duct system in streptozotocin-induced diabetes

In patients with type I diabetes mellitus, clinical studies have demonstrated decreased secretion of pancreatic juice by the pancreatic excretory duct system. The cause of this decrease is unknown, but could involve changes in initial signal transduction pathways or one or more of the electrolyte transport components that subserve regulated fluid secretion. We have compared responsiveness to secretin in pancreatic ducts isolated from healthy and diabetic Hartley guinea pigs and also have compared the expression of CFTR and Na+, K(+)-ATPase in these two groups, as the activities of these two proteins are essential for secretion of pancreatic juice. The increases in cyclic AMP levels evoked by exposure to either 0.1 nM or 0.1 microM secretin were not significantly different in pancreatic ducts isolated from healthy and diabetic guinea pigs nor were levels of CFTR or Na+, K(+)-ATPase expression. By contrast, Na+, K(+)-ATPase activity in pancreatic ducts isolated from diabetic guinea pigs was decreased by 70%, suggesting a change in the enzyme's catalytic properties in the diabetic tissues. The observed decrease would be expected to seriously compromise the production of pancreatic juice.     

Analysis of lipidation of recombinant Lyme vaccine protein (rOspA) by electrospray mass spectroscopy

Lipidation at the N-terminal of recombinant outer surface protein A (rOspA) is an important determinant of its immunogenicity. Lipidation patterns of rOspA can be sensitive to processing environments and storage conditions. In order to assure product consistency and stability. it is essential to characterize and monitor lipidation patterns of rOspA through its life-cycle. Electrospray mass spectroscopy combined with maximum entropy calculation was employed to analyze the lipidation of rOspA. The results revealed that more than 90% of protein is a tri-lipidated rOspA and the remainder is di-lipidated. It was demonstrated that the method is both sensitive and quantitative and has the potential to be used for routine quality control and stability testing.     

Binding constants in the formation of mammalian protein synthesis initiation complexes and the role of mRNA

Acute idiopathic thrombocytopaenic purpura is the most common of the thrombocytopaenias of childhood. Clinically it is associated with petechiae, mucocutaneous bleeding and occasionally haemorrhage into tissues. The oral mucosa is frequently involved. This paper describes a case presenting in general dental practice.     

Laser Doppler flowmetry during open reduction for developmental dysplasia of the hip

Laser Doppler flowmetry was used intraoperatively to monitor femoral head perfusion during open reduction of 13 congenital hip dislocations in 11 patients. Laser Doppler determinations ranged from 12 to 400 mV before reduction and 30 to 300 mV after reduction. Three patients had magnitude changes in excess of 50%. One had increased perfusion, and two had decreased blood flow. Avascular necrosis of the hip occurred in one patient that was not predicted by laser Doppler flowmetry. Femoral head perfusion measured 175 mV for the dislocated hip and 180 mV after reduction of the femoral head and completion of the pelvic osteotomy. The authors conclude that laser Doppler flowmetry is not a reliable method for monitoring femoral head perfusion during open reduction of the hip for developmental hip dysplasia.     

Attitudes toward service use among wife caregivers of frail older veterans

This study investigated (a) attitudes toward service use among wife caregivers of frail older veterans; and (b) the relationship between those attitudes and service utilization by the wives. The study focused on three sets of attitudinal variables: attitudes towards various kinds of dependencies; individual and family ethos concerning service use; and perceptions of responsibility for care. Respondents were 80 wife caregivers of frail older (age 55+) veterans at a Department of Veterans Affairs Medical Center in a Midwestern state. Most caregivers agreed that it is acceptable to get help with the physical care of the husband and to get help themselves for the emotional strains caused by caregiving. Acceptability of a wife's getting help with the physical care of her husband was a positive predictor of number of services ever used and frequency of in-home service use. Wives' view that help from outside agencies should be used only as a last resort was the strongest and most consistent negative predictor of both number of services ever used and frequency of service use.     

Variables that initiate and maintain an early-onset trajectory for juvenile offending

A trajectory defined by three time-ordered events was offered as a useful adjunct to building a development theory about antisocial behaviors. A sequence was defined with significant linkages between antisocial childhood behavior and early arrest and between early arrest and chronic offending. The majority of chronic offenders traveled through all three events in the sequence. Each event in the sequence shared a common process of disrupted family process plus frequent family transitions and marked social disadvantage. The findings support the hypothesis that the process that leads to antisocial behaviors at grade four may also maintain the entire sequence. The level of disrupted process at initiation and a time-based measure of involvement with deviant peers predicted which individuals moved forward in the sequence and which did not. The findings are consistent with the idea that the majority of chronic offending juveniles follow a trajectory that can be explained by a single theory.