Gangliosides and glycophorin are receptors for wheat germ agglutinin. The competitive binding of these molecules to wheat germ agglutinin is studied by electron spin resonance spectroscopy with spin labels attached to the oligosaccharide chains of gangliosides. Evidence shows that glycophorin is more accessible to wheat germ agglutinin binding than gangliosides. The interactions of gangliosides and glycophorin in liposomes is disrupted on low level binding of WGA.
Aminoacylase I (EC. 3.5.1.14) was immobilized by covalent crosslinking to alginate molecules with 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide HCl followed by calcium alginate bead formation for the production of L-phenylalanine from the racemic mixtures of N-acetyl-DL-phenylalanine. Different concentrations of the coupling reagent were tested and the coupling process was optimized. The immobilized and the partially purified aminoacylase were characterized in terms of the activity, operational stability, thermal stability, pH and temperature optima and kinetic constants, Km and Vmax. The activity of the enzyme covalently immobilized in calcium alginate beads was enhanced by about 75% compared to that of free enzyme. The beads showed stable activity under operational conditions, they lost about 40% of their activity after four reaction cycles. The immobilized aminoacylase was more stable over a broader pH range. Thus this simple method provides irreversible immobilization of aminoacylase to give a biocatalyst with good operational stability and enhanced activity.
Aminoacylase I (EC 3.5.1.14) encapsulated in calcium alginate beads stabilized with poly-L-lysine was used for the production of L-phenylalanine by the hydrolysis of a racemic mixture of N-acetyl-DL-phenylalanine. The immobilized aminoacylase was studied with respect to operational stability, thermal stability, effects of pH and temperature and kinetic constants. The leakage of enzyme from the stabilized beads was eliminated. The immobilized enzyme retained high biological activity. The Km and Vmax values for the stabilized beads were 11.11 mmol dm-3 and 0.076 mumol min-1 respectively. The optimum pH and temperature for the hydrolysis were 6.5 and 55 degrees C respectively. Scanning electron micrographs revealed crosslinked structures on the surface of the beads. The operational performances of the beads in a batch reaction and a packed-bed bioreactor for continuous reaction were investigated. With batch reaction, only about 5% of enzyme activity was lost within ten reaction cycles and there was no significant loss of activity over 600 h of continuous operation after equilibrium was reached, and a conversion yield of about 80% was obtained.
Aminoacylase I (E.C.3.5.1.14) was immobilized by entrapment in calcium alginate beads coated with polyethyleneimine for the production of L-phenylalanine by the hydrolysis of a racemic mixture of N-acetyl-DL-phenylalanine. The operational stability in terms of batch operation and continuous reaction in packed-bed bioreactor were studied. Kinetic constants, Km and Vmax values of free and immobilized enzymes were studied. Polyethyleneimine treatment was found to enhance the operational stability of the enzyme though its activity was substantially reduced. When polyethyleneimine-coated calcium alginate beads were packed into packed bed bioreactor, it was stable for at least 25 days under continuous operation without appreciable loss of activity.
Background Tyrosine kinase inhibitors have been demonstrated to improve the survival of patients with chronic myeloid leukaemia. However, medication adherence is vital for patients on chronic treatment. Objective The objective of the current study was to evaluate response to treatment, adherence by patients to tyrosine kinase inhibitors and factors associated with adherence and response. Setting A haematology clinic in a regional referral hospital in Malaysia. Method Patients aged ≥ 13 years who had been on imatinib or nilotinib for ≥ 12 months were included in this cross-sectional study. An optimal response was defined as the achievement of major molecular response at 12 months of treatment. Patient medication adherence was determined using the average medication possession ratio based on the dispensing records. The patients were considered adherent if the medication possession ratio was > 90%. Multiple logistic regression was performed to evaluate the factors associated with adherence. The association of adherence with molecular response was analysed by univariate logistic regression. Main outcome measure The primary outcome measures were the proportion of patients who achieved optimal response and the medication possession ratio. Results A total of 151 patients were screened, and 71 patients were included. Twenty-eight patients (39%) achieved major molecular response at 12 months of treatment. The median time to achieve this was 15.5 months (an interquartile range of 15). The mean medication possession ratio for imatinib and nilotinib was 0.94 (± 0.14) and 0.96 (± 0.10), respectively, but this difference was without statistical significance (t = - 0.517, p = 0.610). Nausea and vomiting (odds ratio [OR] of 0.25, 95% confidence interval [CI]: 0.07-0.83, p = 0.023) and disease phase at diagnosis (OR of 0.20, 95% CI 0.04-1.06, p = 0.059) were associated with patient adherence. An association was not found between patient adherence and molecular response (OR of 1.03, 95% CI 0.35-3.09, p = 0.956). Conclusion The patients in this study demonstrated a relatively deep molecular response and optimal adherence. Nevertheless, one fourth of them were noncompliant with imatinib. Therefore, active interventions are warranted to prevent treatment-associated adverse events and improve adherence.
This commentary shares the experience of a hospital pharmacy department in providing healthcare services during the COVID-19 outbreak in Malaysia. During this pandemic, the medication delivery system is redesigned to minimize contact among patients and the health care providers. Also, the remote medication monitoring system was implemented to deliver pharmaceutical care for inpatients. Communication technology was used to assist the pharmacist in medication counseling. QR codes to access videos demonstrating the use of devices were made available for patients. Pharmacists were also tasked with the procurement of personal protective equipment and medications needed requiring special approval from the Ministry of Health.