Antigenic studies on an enzymatically sialylated carbohydrate: NeuAc(alpha 2-3)Gal(beta 1-3)GalNAc

Sialic acid residues are often the end moiety of the carbohydrate chain of biologically important glycoconjugates. It is difficult to study sialylated glycoconjugates because the purification of these compounds is often laborious yielding only very small amounts of oligosaccharides for study. Chemical synthesis of sialylated compounds is complicated by the labile nature of the sialic acid bond. In both of these cases the sialylated compounds would need to be conjugated to a polypeptide to be an effective immunogen, and again, such conjugation is fraught with problems due to the instability of the sialic acid linkage. We have developed a combined enzymatic and synthetic route for obtaining quantities of sialylated carbohydrates conjugated to a protein carrier in amounts sufficient for antigenic studies. The notable novelty of this protocol is the addition of sialic acid after the carbohydrate-protein conjugation step. Antiserum to the compounds was developed and after absorption, antibodies that demonstrate a requirement for sialic acid for their binding were produced and studied. CA 125 has been shown to be a prognostically significant marker for ovarian adenocarcinoma. The nature of the epitope involved has been analyzed with conflicting results. To attempt to resolve this conflict, we initiated studies on sialylated antigens with NeuAc alpha 2-3Gal beta 1-3GalNAc. This trisaccharide occupies the terminal region in a series of complex carbohydrates which have been suggested to be involved as the epitope. Hanisch et al. reported that the neuraminic acid was important for the reaction.     

Detection of liver fibrosis with magnetic cross-relaxation

The utility of MRI using magnetization transfer (MT) enhanced pulse sequences to diagnose hepatic cirrhosis in a rat model was investigated. Hepatic T₁ was measured with and without MT off-resonance RF pulses in 17 treated and six control rats. The livers were evaluated histologically, and the hydroxyproline content quantitatively measured. We did not find a statistically significant linear correlation between the MR relaxation times and the degree of tissue injury. However, the MR measurements performed with MT were superior to those without differentiating the treated and control groups. Specifically, the T₁ times were 695 ±76 ms for the treated group, versus 748 ± 61 ms in the controls; P= 0.095. The T_1sat times were also lower in the treated group, with statistical significance: 367 ± 51 ms versus 421 ± 38 ms, P = 0.016. Finally, the change in the relaxation rates (the inverse of the relaxation times) with and without saturation were 1.31 ± 0.22 s^?1 (treated group) versus 1.05 ± 0.12 s^?1 (controls), which differed significantly, P= 0.001.     

Maxillary and mandibular occlusal photographs

Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result.     

The therapeutic antibodies market to 2008.

The therapeutic biologics market is currently dominated by recombinant protein products. However, many of these products are mature, and growth of the biologics market will increasingly rely on the expansion of the therapeutic monoclonal antibody sector. Successive technology waves have driven the growth of the monoclonal antibody sector, which is currently dominated by chimeric antibodies. Chimeric products, led by Remicade and Rituxan, will continue to drive market share through to 2008. However, over the forecast period, humanized and fully human monoclonal antibodies, together with technologies such as Fabs and conjugated antibodies, will play an increasingly important role, driving monoclonal antibody market growth at a forecast compound annual growth rate of 20.9%, to reach $16.7 billion by 2008. In terms of therapeutic focus, the monoclonal antibody market is heavily focused on oncology and arthritis, immune and inflammatory disorders, and products within these therapeutic areas are set to continue to be the key growth drivers over the forecast period. Underlying the growth of the market is the evolution of the monoclonal antibody company business model, set to transition towards the highly successful innovator model.     

Symptom profile and asthma control in school-aged children.

BACKGROUND: Children with poorly controlled asthma are at high risk of airway remodeling, sleep disruption, school absenteeism, and limited participation in activities. OBJECTIVE: To determine asthma prevalence and characterize disease severity and burden in school-aged children. METHOD: A case-finding study was conducted via a multiple-choice questionnaire and asthma algorithm. Items used for analysis include physician diagnosis of asthma, symptom severity, and health care utilization. The chi2 test was used to determine the significance of differences among cases. Logistic regression was used to evaluate the association of patient factors and asthma indicators. RESULTS: Of the 5,417 children surveyed, 1,341 (25%) were classified as being at risk of asthma. Of these asthma cases, 55% were positive by diagnosis and algorithm (active), 10% were positive per algorithm alone (suspected), and 35% were positive per diagnosis alone (nonactive). Only 14% of all asthma cases reported experiencing no respiratory symptoms (< 1% active, 2% suspected, and 40% nonactive) compared with 75% of noncases. Also, 75% of noncases reported never missing school compared with 19%, 33%, and 54% of active, suspected, and nonactive asthma cases. African American race, Medicaid enrollment, and male sex were independent predictors of asthma risk. Similarly, African American race, Medicaid enrollment, age, and persistent asthma were independent predictors of emergency department use among asthma cases. DISCUSSION: Prevalence of active symptoms suggestive of poor asthma control was extremely high among urban, minority children enrolled in Arkansas' largest public school district. Poor asthma control greatly affects quality of life, including school attendance and performance. Interventions should raise expectations and emphasize the importance of achieving asthma control.     

An animal model of chronic inflammatory pain: pharmacological and temporal differentiation from acute models.

Clinically, inflammatory pain is far more persistent than that typically modelled pre-clinically, with the majority of animal models focussing on short-term effects of the inflammatory pain response. The large attrition rate of compounds in the clinic which show pre-clinical efficacy suggests the need for novel models of, or approaches to, chronic inflammatory pain if novel mechanisms are to make it to the market. A model in which a more chronic inflammatory hypersensitivity phenotype is profiled may allow for a more clinically predictive tool. The aims of these studies were to characterise and validate a chronic model of inflammatory pain. We have shown that injection of a large volume of adjuvant to the intra-articular space of the rat knee results in a prolonged inflammatory pain response, compared to the response in an acute adjuvant model. Additionally, this model also results in a hypersensitive state in the presence and absence of inflammation. A range of clinically effective analgesics demonstrate activity in this chronic model, including morphine (3mg/kg, t.i.d.), dexamethasone (1mg/kg, b.i.d.), ibuprofen (30mg/kg, t.i.d.), etoricoxib (5mg/kg, b.i.d.) and rofecoxib (0.3-10mg/kg, b.i.d.). A further aim was to exemplify the utility of this chronic model over the more acute intra-plantar adjuvant model using two novel therapeutic approaches; NR2B selective NMDA receptor antagonism and iNOS inhibition. Our data shows that different effects were observed with these therapies when comparing the acute model with the model of chronic inflammatory joint pain. These data suggest that the chronic model may be more relevant to identifying mechanisms for the treatment of chronic inflammatory pain states in the clinic.     

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Fructose metabolism in the adult mouse optic nerve, a central white matter tract.

Our recent report that fructose supported the metabolism of some, but not all axons, in the adult mouse optic nerve prompted us to investigate in detail fructose metabolism in this tissue, a typical central white matter tract, as these data imply efficient fructose metabolism in the central nervous system (CNS). In artificial cerebrospinal fluid containing 10 mmol/L glucose or 20 mmol/L fructose, the stimulus-evoked compound action potential (CAP) recorded from the optic nerve consisted of three stable peaks. Replacing 10 mmol/L glucose with 10 mmol/L fructose, however, caused delayed loss of the 1st CAP peak (the 2nd and 3rd CAP peaks were unaffected). Glycogen-derived metabolic substrate(s) temporarily sustained the 1st CAP peak in 10 mmol/L fructose, as depletion of tissue glycogen by a prior period of aglycaemia or high-frequency CAP discharge rendered fructose incapable of supporting the 1st CAP peak. Enzyme assays showed the presence of both hexokinase and fructokinase (both of which can phosphorylate fructose) in the optic nerve. In contrast, only hexokinase was expressed in cerebral cortex. Hexokinase in optic nerve had low affinity and low capacity with fructose as substrate, whereas fructokinase displayed high affinity and high capacity for fructose. These findings suggest an explanation for the curious fact that the fast conducting axons comprising the 1st peak of the CAP are not supported in 10 mmol/L fructose medium; these axons probably do not express fructokinase, a requirement for efficient fructose metabolism.