Establishing a Link Between Amino Acid Sequences and Self-Associating and Viscoelastic Behavior of Two Closely Related Monoclonal Antibodies

Purpose  

To investigate the underlying cause for the observed differences in self-associating and viscoelastic behavior between two monoclonal antibodies, MAb1, and MAb2.     

In vitro reactivation of sarin-inhibited human acetylcholinesterase (AChE) by bis-pyridinium oximes connected by xylene linkers

A series of bis-pyridinium oximes connected by xylene linkers were synthesized and their in vitro reactivation potential was evaluated against human acetylcholinesterase (hAChE) inhibited by nerve agent sarin and the data were compared with 2-PAM and obidoxime. Among the synthesized compounds, N,N′-p-xylene-bis-[(2,2′-hydroxyiminomethyl)pyridinium] dibromide (3c) was found to be the most potent reactivator for hAChE inhibited by sarin. The oxime 3c exhibited 45% regeneration of inhibited hAChE, in comparison to 34% and 24% regeneration by 2-PAM and obidoxime, respectively, at a concentration of 10⁻³ M within 10 min. The higher reactivation efficacies of these oximes were attributed to their acid dissociation constants (pKa). The pKa values of all the oximes were determined spectrophotometrically and correlated with their observed reactivation potential. This method involving the in vitro reactivation of inhibited hAChE may be useful for the screening of new oximes as reactivators.     

Opposite Effects of Polyols on Antibody Aggregation: Thermal <Emphasis Type="Italic">Versus</Emphasis> Mechanical Stresses

Purpose  

To investigate the physical stability of antibody-polyol formulations under thermal and mechanical stresses.     

Esophageal replacement in the neonatal period in infants with esophageal atresia and tracheoesophageal fistula

Aim

The aim of the study was to assess the outcome after esophageal replacement using gastric pull-up performed in critically ill neonates with esophageal atresia (EA) and tracheoesophageal fistula.

Methods

During 1998 to 2005, gastric transposition was performed in 27 neonates (mean birth weight, 2.32 kg [1.86-3.0 kg]; mean age, 6.08 days) for post-EA and tracheoesophageal fistula leaks in 17, long gap in 6, and pure EA in 4, using transhiatal route in all. Pyloromyotomy as the drainage procedure was added for all 27 neonates. Patients were followed up at 3, 6, and 12 months for clinical evaluation, gastric clearance, duodenogastric reflux, and gastric pressure profile.

Results

Six neonates had ongoing serious chest infection, 3 had lung collapse, and 2 had associated congenital heart disease. Postoperative elective ventilation was provided to all neonates for 2 to 40 days (mean, 10.6 days). Nine neonates developed postoperative leaks in the neck; all healed spontaneously before discharge. Mean hospital stay was 32.6 days (range, 9-87 days). Four newborns died on postoperative days 9, 13, 15, and 29 because of existing severe sepsis in 3 and major congenital heart disease in 1. Functional evaluations were done at 3, 6, and 12 months postoperatively. Values at 6 months revealed normal gastric emptying in 16 of 23, presence of duodenal gastric reflux in 11 of 23, and mass contractions with significant rise in intragastric pressure after bolus feeds in 16 of 23 cases. Values at 12months revealed normal gastric emptying in 14 of 20, presence of duodenal gastric reflux in 8 of 20, and mass contractions with significant rise in intragastric pressure after bolus feeds in 13 (65%) of 20cases.

Conclusion

Gastric transposition could be a lifesaving alternative to diversion, even in the critically ill newborns after major leaks. However, it requires technical surgical expertise and an effective pain relief and neonatal intensive care.     

Prognostic value of tissue polypeptide antigen in oral squamous cell carcinoma

Human oral cancer has a high risk of locoregional relapse which is difficult to diagnose early due to lack of prognostic markers. We and others have shown aberrant expression of cytokeratin (CK) 8 and 18 in human oral cancer. Aberrant supra-basal expression of CK19 has been shown earlier. In this study, our aim was to develop a non-invasive test for prognostication of human oral cancer. Immunoradiometric assay (IRMA) was used to measure the circulating levels of TPA in the sera of 80 oral cancer patients before surgery and seven days after surgery. Elevated serum TPA levels were noted in the post surgery samples of 28 out of the 50 patients for whom clinical follow-up was available, as compared to their pre-surgery samples. TPA levels in the pre-surgery serum samples of patients were significantly higher than levels in the sera of healthy controls (p=0.001). Elevated levels in patients correlated significantly with stage (p=0.02), development of recurrence (p<0.006), and impacted survival (p<0.033). IHC analysis showed statistically significant correlation between expression of CK8, 18 and 19 in surrounding uninvolved tissues of the tumour and post surgery elevated serum TPA levels (p<0.001). This suggests the possibility that CK fragments are released from the surrounding uninvolved tissues into the sera of patients after surgical removal of the tumour. Thus, our study indicates that TPA can be a useful tumour marker for the prediction of recurrence and poor prognosis in human oral cancer.     

Imbalances in dietary consumption of fatty acids, vegetables, and fruits are associated with risk for Crohn's disease in children

BACKGROUND AND OBJECTIVES: The role of dietary factors in the etiology of Crohn's disease (CD) is inconsistent largely due to difficulties in acquiring valid information on consumption habits. We examined the impact of diet on new onset CD in children using a validated food-frequency questionnaire (FFQ). METHODOLOGY: A case-control study was carried out. Children < or =20 yr, newly diagnosed with CD, were recruited from 3 pediatric gastroenterology clinics across Canada. Population or hospital controls were selected matched to cases for time of diagnosis (+/-6 months) and area of residence. Dietary consumption 1 yr prior to disease diagnosis was evaluated using a validated FFQ, administered within 1 month of diagnosis. Conditional logistic regression analysis adjusting for potential confounding variables (energy intake, age, gender, body mass index) was carried out. RESULTS: A total of 130 CD patients and 202 controls were studied. Mean age at diagnosis (+/-SD) was 14.2 (2.7). There were more male patients (59%). Comparing the highest to the lowest levels of consumption, higher amounts of vegetables (OR 0.69, 95% CI 0.33-1.44, P= 0.03), fruits (OR 0.49, 95% CI 0.25-0.96, P= 0.02), fish (OR 0.46, 95% CI 0.20-1.06, P= 0.02), and dietary fiber (OR 0.12, 95% CI 0.04-0.37, P < 0.001) protected from CD. Consumption of long-chain omega-3 fatty acids (LCN-omega-3) was negatively associated with CD (OR 0.44, 95% CI 0.19-1.00, P < 0.001). A higher ratio of LCN-omega-3/omega-6 fatty acids was significantly associated with lower risks for CD (OR 0.32, 95% CI 0.14-0.71, P= 0.02). CONCLUSIONS: Our findings indicate that an imbalance in consumption of fatty acids, vegetables, and fruits is associated with increased risks for CD among Canadian children.     

Overexpression of cerebral and hepatic cytochrome P450s alters behavioral activity of rat offspring following prenatal exposure to lindane

Oral administration of different doses (0.0625, 0.125 or 0.25 mg/kg corresponding to 1/1400th, 1/700th or 1/350th of LD(50)) of lindane to the pregnant Wistar rats from gestation days 5 to 21 were found to produce a dose-dependent increase in the activity of cytochrome P450 (CYP)-dependent 7-ethoxyresorufin-O-deethylase (EROD), 7-pentoxyresorufin-O-dealkylase (PROD) and N-nitrosodimethylamine demethylase (NDMA-d) in brain and liver of offspring postnatally at 3 weeks. The increase in the activity of CYP monooxygenases was found to be associated with the increase in the mRNA and protein expression of xenobiotic metabolizing CYP1A, 2B and 2E1 isoenzymes in the brain and liver of offspring. Dose-dependent alterations in the parameters of spontaneous locomotor activity in the offspring postnatally at 3 weeks have suggested that increase in CYP activity may possibly lead to the formation of metabolites to the levels that may be sufficient to alter the behavioral activity of the offspring. Interestingly, the inductive effect on cerebral and hepatic CYPs was found to persist postnatally up to 6 weeks in the offspring at the relatively higher doses (0.125 and 0.25 mg/kg) of lindane and up to 9 weeks at the highest dose (0.25 mg/kg), though the magnitude of induction was less than that observed at 3 weeks. Alterations in the parameters of spontaneous locomotor activity in the offspring postnatally at 6 and 9 weeks, though significant only in the offspring at 3 and 6-week of age, have further indicated that due to the reduced activity of the CYPs during the ontogeny, lindane and its metabolites may not be effectively cleared from the brain. The data suggest that low dose prenatal exposure to the pesticide has the potential to produce overexpression of xenobiotic metabolizing CYPs in brain and liver of the offspring which may account for the behavioral changes observed in the offspring.     

Design, synthesis and biological evaluation of ligands selective for the melanocortin-3 receptor

The processed products of the proopiomelanocortin gene (ACTH, alpha-MSH, beta-MSH, gamma-MSH, etc.) interact with five melanocortin receptors, the MC1R, MC2R, MC3R, MC4R, and MC5R to modulate and control many important biological functions crucial for good health both peripherally (as hormones) and centrally (as neurotransmitters). Pivotal biological functions include pigmentation, adrenal function, response to stress, fear/flight, energy homeostasis, feeding behavior, sexual function and motivation, pain, immune response, and many others, and are believed to be involved in many disease states including pigmentary disorders, adrenal disorders, obesity, anorexia, prolonged and neuropathic pain, inflammatory response, etc. The melanocortin-3 receptor (MC3R) is found primarily in the brain and spinal cord and also in the periphery, and its biological functions are still not well understood. Here we review some of the biological functions attributed to the MC3R, and then examine in more detail efforts to design and synthesize ligands that are potent and selective for the MC3R, which might help resolve the many questions still remaining about its function. Though some progress has been made, there is still much to be done in this critical area.