Enhancing titre and production stability of paenibacillin from Paenibacillus polymyxa by sequential drug resistance screening.

AIMS: Paenibacillin is a naturally biosynthesized antimicrobial lantibiotic peptide which is produced by wild-type Paenibacillus polymyxa OSY-DF in low but detectable levels. The aim was to increase paenibacillin titre and production consistency through sequential drug resistance screening. METHODS AND RESULTS: Spontaneous mutants of P. polymyxa OSY-DF were isolated by subjecting the bacterium to two rounds of screening for resistance to rifampicin, which targets RNA polymerase, and gentamicin, which targets ribosomes. Changes in antimicrobial production of the mutants were monitored using a bioassay method. A spontaneous mutant, P. polymyxa OSY-EC, capable of producing high paenibacillin titre, was selected and compared phenotypically to the wild-type strain. The mutant was found to produce paenibacillin at five-fold higher titre than the wild type. The mutant constantly produced paenibacillin while the wild type produced the antimicrobial agent variably. Fourier transformation mid-infrared spectroscopy revealed an interclass distance of 6·4 between the wild type and the mutant strain, suggesting significant phenotypic change during the mutation. CONCLUSIONS: P. polymyxa OSY-EC, a spontaneous mutant capable of consistent production of high paenibacillin titre, was isolated from the wild type after sequential screening on rationally selected antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The study will help make paenibacillin available for large-scale testing by interested researchers and industries seeking applications that improve food safety and quality.

Differential contribution of TM6 and TM12 to the pore of CFTR identified by three sulfonylurea-based blockers.

Previous studies suggested that four transmembrane domains 5, 6, 11, 12 make the greatest contribution to forming the pore of the CFTR chloride channel. We used excised, inside-out patches from oocytes expressing CFTR with alanine-scanning mutagenesis in amino acids in TM6 and TM12 to probe CFTR pore structure with four blockers: glibenclamide (Glyb), glipizide (Glip), tolbutamide (Tolb), and Meglitinide. Glyb and Glip blocked wildtype (WT)-CFTR in a voltage-, time-, and concentration-dependent manner. At V (M) = -120 mV with symmetrical 150 mM Cl(-) solution, fractional block of WT-CFTR by 50 µM Glyb and 200 µM Glip was 0.64 ± 0.03 (n = 7) and 0.48 ± 0.02 (n = 7), respectively. The major effects on block by Glyb and Glip were found with mutations at F337, S341, I344, M348, and V350 of TM6. Under similar conditions, fractional block of WT-CFTR by 300 µM Tolb was 0.40 ± 0.04. Unlike Glyb, Glip, and Meglitinide, block by Tolb lacked time-dependence (n = 7). We then tested the effects of alanine mutations in TM12 on block by Glyb and Glip; the major effects were found at N1138, T1142, V1147, N1148, S1149, S1150, I1151, and D1152. From these experiments, we infer that amino acids F337, S341, I344, M348, and V350 of TM6 face the pore when the channel is in the open state, while the amino acids of TM12 make less important contributions to pore function. These data also suggest that the region between F337 and S341 forms the narrow part of the CFTR pore.

Complete 180° rotatory dislocation in a mobile-bearing knee prothesis.

Dislocation of the rotator platform in mobile-bearing total knee arthroplasty is a well-documented, albeit uncommon, phenomenon. A review of the literature has revealed multiple case reports describing spin out to 90° or complete extrusion of the polyethylene component. Closed reduction may be attempted in the acute presentation followed by revision if instability persists. We present a case of a 57-year-old woman who had a partial rotatory subluxation of her polyethylene component and underwent closed reduction resulting in a full 180° spinout. To our knowledge, this has not been described in the literature and should be considered as a possibility after closed reduction attempts. She was treated successfully with open exploration and poly exchange using a larger component.

Atypical fractures on long term bisphosphonates therapy.

Bisphosphonates reduce fractures risk in patients with osteoporosis. A new pattern of fractures is now being noted in patients on prolonged bisphosphonate therapy. We report a case of an atypical femoral fracture with preceding pain and highlight the characteristics of these fractures.

Ten-year experience with multidisciplinary diagnosis and treatment of odontogenic sinusitis.

BACKGROUND: Odontogenic sinusitis is an underdiagnosed entity and is one cause of failure of conventional treatments of sinusitis. Unfortunately, there is no consensus so far on the best management protocol. This retrospective study aimed to suggest a practical management protocol that can reduce misdiagnosis and improve treatment outcomes. METHODS: The study included 74 patients with confirmed odontogenic sinusitis who were diagnosed and treated over 10 years (2010-2019). The patient data were recorded and analysed. RESULTS: Dental pain was reported in only 31.1 per cent of patients. Fifty-six patients (75.7 per cent) had received dental treatment during the last year, but only 13 (23.1 per cent) reported it. Dental pathology was missed on initial computed tomography evaluation in 24 patients (32.4 per cent). Forty-one patients (55.4 per cent) were successfully treated by dental procedures and antibiotics. Fourteen patients needed functional endoscopic sinus surgery in addition to dental procedures. CONCLUSION: Successful management of odontogenic sinusitis requires good communication between rhinologists, radiologists and dentists. Dental treatment should be the logical first step in the treatment protocol, unless otherwise indicated.

Fixed-dose combination in management of type 2 diabetes mellitus: Expert opinion from an international panel.

Type 2 diabetes mellitus (T2DM) is a progressive disease with multifactorial etiology. The first-line therapy includes monotherapy (with metformin), which often fails to provide effective glycemic control, necessitating the addition of add-on therapy. In this regard, multiple single-dose agents formulated as a single-dose form called fixed-dose combinations (FDCs) have been evaluated for their safety, efficacy, and tolerability. The primary objective of this review is to develop practice-based expert group opinion on the current status and the causes of concern regarding the irrational use of FDCs, in Indian settings. After due discussions, the expert group analyzed the results from several clinical evidence in which various fixed combinations were used in T2DM management. The panel opined that FDCs (double or triple) improve patient adherence, reduce cost, and provide effective glycemic control and, thereby, play an important role in the management of T2DM. The expert group strongly recommended that the irrational metformin FDC's, banned by Indian government, should be stopped and could be achieved through active participation from the government, regulatory bodies, and health ministry, and through continuous education of primary care physicians and pharmacists. In T2DM management, FDCs play a crucial role in achieving glycemic targets effectively. However, understanding the difference between rational and irrational FDC combinations is necessary from the safety, efficacy, and tolerability perspective. In this regard, primary care physicians will have to use a multistep approach so that they can take informed decisions.

Unravelling the utility of modern sulfonylureas from cardiovascular outcome trials and landmark trials: expert opinion from an international panel.

AIM: The primary objective of this review is to develop practice-based expert group opinions on the cardiovascular (CV) safety and utility of modern sulfonylureas (SUs) in cardiovascular outcome trials (CVOTs). BACKGROUND: The United States Food and Drug Administration issued new guidance to the pharmaceutical industry in 2008 regarding the development of new antihyperglycemic drugs. The guidance expanded the scope for the approval of novel antihyperglycemic drugs by mandating CVOTs for safety. A few long-term CVOTs on dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor agonists, and sodium-glucose cotransporter 2 inhibitors have been completed, while others are ongoing. SUs, which constitute one of the key antihyperglycemic agents used for the management of type 2 diabetes mellitus (T2DM), have been used as comparator agents in several CVOTs. However, the need for CVOTs on modern SUs remains debatable. In this context, a multinational group of endocrinologists convened for a meeting and discussed the need for CVOTs of modern SUs to evaluate their utility in the management of patients with T2DM. At the meeting, CVOTs of modern SUs conducted to date and the hypotheses derived from the results of these trials were discussed. REVIEW RESULTS: The expert group analyzed the key trials emphasizing the CV safety of modern SUs and also reviewed the results of various CVOTs in which modern SUs were used as comparators. Based on literature evidence and individual clinical insights, the expert group opined that modern SUs are cardiosafe and that since they have been used as comparators in other CVOTs, CVOTs of SUs are not required. CONCLUSION: Modern SUs can be considered a cardiosafe option for the management of patients with diabetes mellitus and CV disease; thus CVOTs among individuals with T2DM are not required.

Angiotensin-1 converting enzyme (ACE) polymorphism in patients presenting with myocardial infarction or unstable angina.

A deletion/insertion polymorphism in the ACE gene has been reported previously as a potent factor for myocardial infarction. We have tested the frequency of the deletion (D) allele of the ACE gene in 308 consecutive patients admitted to coronary care with chest pain. The gene frequencies were compared with those of 348 controls recruited from the London area. Of 108 Caucasian patients with myocardial infarction, the DD genotype was found more frequently than the combined DI and II genotypes (Chi-square, chi 2 = 5.07, 2P = 0.024). The overall D gene frequency was higher in myocardial infarction patients (125 of 216, 58%) than in controls (347 of 696, 49.9%) (chi 2 = 3.79, 2P = 0.052). In contrast, the DD genotype and D allele frequencies in patients with unstable angina were similar to those found in our normal population. A nonsignificant difference in allele frequency between myocardial infarction and unstable angina patients was observed but the small numbers of subjects studied precludes a more formal comparison. Since unstable angina and myocardial infarction represent a spectrum of coronary thrombosis, it is possible that the DD genotype favours the development of myocardial infarction, perhaps through the presence of higher serum ACE concentrations.

Autoantibodies to IA-2 and GAD65 in patients with type 2 diabetes mellitus of varied duration: prevalence and correlation with clinical features.

OBJECTIVE: To determine the prevalence of autoantibodies to IA-2 (IA-2Ab) and glutamic acid decarboxylase (GADAb) in type 2 diabetes, their relationship to disease duration, and their importance in management decisions. METHODS: We undertook a study of 101 patients with type 2 diabetes (defined as nonketotic hyperglycemia at diagnosis) of varied duration (median, 4 years). Results were compared with those from 36 patients with type 1 diabetes also of varied duration (median, 2 years). IA-2Ab and GADAb were measured by radioligand-binding assays with use of in vitro-synthesized, 35S-labeled antigens. RESULTS: Of the 101 patients with type 2 diabetes, 20 (20%) were positive for GADAb; only 4 of these 20 were positive for IA-2Ab. In comparison, 75% of patients with type 1 diabetes were positive for GADAb, IA-2Ab, or both (P<0.0001). The coincidence of IA-2Ab positivity in GADAb-positive patients with type 2 diabetes was significantly lower than in patients with type 1 diabetes (20% versus 73%, respectively; P = 0.002). All four IA-2Ab- and GADAb-positive patients with type 2 diabetes required insulin and were younger than those positive for GADAb alone (P = 0.018). GADAb positivity in patients with type 2 diabetes was highly associated with insulin requirement (P = 0.004), with an odds ratio of 5.8 in predicting insulin dependence. Among patients with type 2 diabetes receiving insulin therapy, disease duration was significantly shorter (P = 0.025) and body mass index was significantly lower (P<0.001) in GADAb-positive versus GADAb-negative patients. In contrast to type 1 diabetes, in which GADAb values were negatively correlated with disease duration (r = -0.34; P = 0.044), no significant correlation with disease duration was observed in type 2 diabetes (r = -0.166; P = 0.48). CONCLUSION: Irrespective of duration of disease, measurement of IA-2Ab and GADAb can help to identify those patients with type 2 diabetes most likely to require insulin therapy.

Cathodic voltammetry of riboflavin at platinum and gold rotating disc electrodes.

The electroreduction of riboflavin (FMN) has been examined by cathodic rotating disc voltammetry in acidic and basic media at platinum and gold electrodes. It has proved to be diversely reducible best at gold electrode in the alkaline media. Rapid voltametric determination of the substance at gold electrode was effective and gave a mean standard deviation of 1%. Riboflavin at platinum electrode is cathodically active but the voltammograms do not obey the Levich relationship and adsorption destroys the electrode activity. The technique can be conveniently applied to the rapid determination of riboflavin in pure solution and in formulated products.

Cyclic voltammetric adsorption behaviour of riboflavin at platinum electrode.

Cyclic voltammetric technique has been used to determine the electrochemical adsorption behaviour of riboflavin at platinum disc electrode in acidic solution. The electrode loses its activity after the first cyclic curve due to coating of its surface with the adsorbed species. The adsorption strength of riboflavin has been compared with some of the strongly adsorbed materials. This technique is employed to determine the amount of the species adsorbed on the surface of the electrode as the quantity of charge consumed is proportional to the area under the first cycle in the voltammogram.

Conductometric study of interaction between dyes and surface active agents.

The interaction of anionic surface active agents e.g. sodium decyl sulphate (SDS), sodium dodecyl sulphate (SDDS), sodium tetradecyl sulphate (STDS), sodium hexadecyl sulphate (DHDS) and sodium octadecyl sulphate (DODS) with cationic dyes, methylene blue (MB), crystal violet (CV) acridine orange (AO), rhodamine 6G (Rh 6G) and quinacrine dihydrochloride (QD) has been studied in three regions by conductometric titration. In the first region ion pair association occurs and the species (cationic and anionic) exist in equilibrium with homogeneous solution. In the second region complexation occurs by 1:1 with MB, CV and AO and by 2:1 with QD and Rh 6G forming a heterogeneousphase, separation and equilibration containing free ions and ion-pair. In the third region the micelle formation occurs by the excess of anions in the presence of cations as well as ion-pair formation and separated complex ions that give solubilization of the complex to a homogeneous clear solution.

Anodic voltammetry of norgaman at rotating disc platinum and gold electrodes.

Norgaman has been examined by anodic rotating disc electrode voltammetry in buffered media over the range of pH from 0-11.5. The best medium is 0.1 mol 1(-1) sulphuric acid in which the anodic wave is well defined at lower rotation speeds. The compound does not show obedience to the Levich relationship at platinum and gold electrodes. Rapid determination of the compound is not possible due to the adsorption of the oxidation product. Electrode mechanism for the reaction has been elucidated.

Ultrasonic sensor for predicting sugar concentration using multivariate calibration.

This paper presents a multivariate regression method for the prediction of maltose concentration in aqueous solutions. For this purpose, time and frequency domain of ultrasonic signals are analyzed. It is shown, that the prediction of concentration at different temperatures is possible by using several multivariate regression models for individual temperature points. Combining these models by a linear approximation of each coefficient over temperature results in a unified solution, which takes temperature effects into account. The benefit of the proposed method is the low processing time required for analyzing online signals as well as the non-invasive sensor setup which can be used in pipelines. Also the ultrasonic signal sections used in the presented investigation were extracted out of buffer reflections which remain primarily unaffected by bubble and particle interferences. Model calibration was performed in order to investigate the feasibility of online monitoring in fermentation processes. The temperature range investigated was from 10 °C to 21 °C. This range fits to fermentation processes used in the brewing industry. This paper describes the processing of ultrasonic signals for regression, the model evaluation as well as the input variable selection. The statistical approach used for creating the final prediction solution was partial least squares (PLS) regression validated by cross validation. The overall minimum root mean squared error achieved was 0.64 g/100 g.

Reproductive health in Irish female renal transplant recipients.

OBJECTIVE: To report the pregnancy outcomes in Irish female renal transplant recipients on modern maintenance immunosuppression. METHODS: The Republic of Ireland transplant database was accessed to identify the patient cohort in question. All female renal transplant recipients whose transplantation was in Ireland before or during their reproductive years were included. A questionnaire was sent to the identified women. A chart review was performed for those women who reported a pregnancy following renal transplantation. RESULTS: Two hundred and ten women met the inclusion criteria. There was a response rate of 70% (n = 148). Eighteen women reported 29 pregnancies. The live birth rate was 76%. The mean gestation of the live births was 36.2 weeks with a mean birth weight of 3.0 kg. There were six cases of pre-eclampsia. Twin pregnancies and those entering pregnancy with a creatinine greater than 135 µmol/l had particularly complicated clinical courses. Four women had not conceived post transplant despite actively trying for over 1 year. Two women utilised assisted fertility methods (in vitro fertilisation), one of whom became pregnant. CONCLUSIONS: A significant proportion of women who attempt to conceive following renal transplantation are successful, without the use of assisted fertility. Pregnancy in this setting warrants meticulous multidisciplinary care.