New optical scheme for a polarimetric-based glucose sensor

A new optical scheme to detect glucose concentration in the aqueous humor of the eye is presented. The ultimate aim is to apply this technique in designing a new instrument for, routinely and frequently, noninvasively monitoring blood glucose levels in diabetic patients without contact (no index matching) between the eye and the instrument. The optical scheme exploits the Brewster reflection of circularly polarized light off of the lens of the eye. Theoretically, this reflected linearly polarized light on its way to the detector is expected to rotate its state of polarization, owing to the presence of glucose molecules in the aqueous humor of a patient's eye. An experimental laboratory setup based on this scheme was designed and tested by measuring a range of known concentrations of glucose solutions dissolved in water. (c) 2004 Society of Photo-Optical Instrumentation Engineers.     

The Knoevenagel reaction of malononitrile with acetylacetone: New route of pyrazole,pyrazolo[2,3-C]pyridine,benzene, pyridazine and benzo[C]pyridazine derivatives

The Knoevenagal reaction of malononitrile and acetylacetonegave the acyclic product 3 whichwas separated in a good yield and identified. The reactivity of 3 towards some chemical reagents is studied. Thus, the reaction of 3 with aromatic aldehydes, hydrazines and cyanomethylene derivativesgave products 6–12. Reaction of 3 with benzenediazonium chloridegave the primidine derivative 14.     

Arginine: mediator or modulator of sepsis?

Arginine is a conditionally essential amino acid that plays pivotal roles in maintaining body homeostasis. Arginine is a substrate for protein synthesis but can also be metabolized to various bioactive compounds that include nitric oxide, ornithine, polyamines, creatine phosphate, agmatine, and dimethylarginines. Arginine produces physiologic effects via nitric oxide dependent and independent pathways. Nitric oxide is important for the modulation of vascular tone, inflammation, immune function, endothelial function, platelet and leukocyte adherence, and neurotransmission. Nitric oxide modulates many biochemical processes important for the response to sepsis. Arginine, independent of nitric oxide, is important for growth, wound healing, cardiovascular function, immune function, inflammatory responses, energy metabolism, urea cycle function, and other metabolic processes. Arginine supplementation improves outcomes in animals with sepsis, wounds, ischemia-reperfusion injury, and following thermal injury. Enteral administration of arginine improves endothelial function but has little effect upon hemodynamics during human sepsis. An analysis of clinical studies using enteral formulas with supplemental arginine suggests benefits upon outcome, with no evidence of significant detrimental effects.     

Developing fMRI protocol for clinical use Comparison of 6 Arabic paradigms for brain language mapping in native Arabic speakers

Objectives:To assess a baseline assessment using developed functional magnetic resonance imaging (fMRI) language paradigms for Arabic-speakers.Methods:24-healthy right-handed volunteers scanned on a 3.0 Tesla MRI machine. For fMRI, a BOLD-sensitive sequence used to measure signals over time across 6 language paradigms: rhyming (RH), semantic category generations (SCG), silent word generation (SWG), verb generation picture (VGp), verb generation word (VGw), and verb generation audio (VGa). fMRI data was analyzed using FMRIB Software Library (FSL).Results:We found that VGa, SWG, VGw and VGp robustly activated language-related regions in the dominant hemisphere. RH and SCG failed to adequately define these activation regions but this may be related to the study’s preliminary nature and limitations. After assessment of their validity, considerable activation of the inferior frontal gyrus during VGa, SWG, VGw and VGp suggests that these paradigms have the potential for localizing of Broca’s area in native Arabic speakers.Conclusion:Set of well adapted, and evidence-based, fMRI paradigms were established for Arabic-speakers to enable accurate and sufficient localization and lateralization of the language area. After validation, these paradigms may provide sequences for accurate localization of brain language areas, and could be used as a presurgical evaluation tool.

Functional magnetic resonance imaging (fMRI) allows precise, and non-invasive, localization and lateralization of brain functions. Clinically, these techniques have considerable success, and hold great potential in the management of a variety of neurological disorders. One of the most promising clinical applications of fMRI is presurgical linguistic mapping.1-5 The 3 classical language areas that are involved in language production and processing are Broca’s and Wernicke’s areas, and angular gyrus. Wernicke’s area can be described as a receptive region, for processing and integrating auditory sensory information, while Broca’s area can be described as a productive region, for making vocal signals, and meaningful words or sentences. The latter includes pars opercularis and triangularis. The angular gyrus area is particularly involved in reading and transitioning between written and spoken forms of language. Injury to language regions produces noticeable clinical deficits, and the location of these regions may become difficult to assess without advanced anatomical imaging such as fMRI. Internationally, fMRI replaces the more invasive Wada test (also known as the intracarotid sodium amobarbital procedure) in lateralizing language and memory at some centers.6,7Language is a highly complex system that markedly varies across individuals. Patients native language affects brain activation responses during fMRI scans.8-13 As such, language paradigms for presurgical fMRI mapping should be developed and validated using native language paradigms. Language dominance of the left cerebral hemisphere has been well researched and established, but native language and social factors were also reported to play a key role in cortical association of verbal processing.8,14-16Although language localization using fMRI has been routinely used in western countries, and more recently in an Arabic country,17 studies clearly demonstrated that different cultures may process language in different manners, using different brain mechanisms.8,14-16 Existing language paradigms, created for non-Arabic speaking patients, require major modifications before applying them in examining native Arabic speakers.17Language lateralization is another broadly used clinical application of fMRI. Concordance with Wada test has long been demonstrated and validated in the literature using paradigms with various tasks such as verbal fluency, comprehension, and semantic judgment .18-21 These have shown that concordance with Wada test can reach 90% in temporal lobe epilepsy, especially in left-dominant patients. A slightly lower concordance was achieved in right-dominant patients. Although fMRI language lateralization works well for patients with typical language dominance, clinicians need to be careful when interpreting results of patients with atypical language representation.22Semitic languages such as Arabic differ from other languages in many aspects, including orthography (including diacritics), phonology, and syntax. Therefore, significant research in developing and validating language paradigms for Arabic is required. To our knowledge, very few studies in this domain have been carried out.17,23 One developed several language and memory paradigms in neurological patients, while emphasizing consideration for educational and cultural adjustments,17 and the other examined neuronal correlates of diacritics (vs. lack of thereof) in 11 healthy men.23We aim to establish tasks adapted to the Arabic language, that also reliably activate Broca’s and Wernicke’s areas in a relatively short scanning time. This study is a baseline assessment using 6 developed fMRI language paradigms for Arabic-speaking presurgical candidates. The desired outcome of this work is to create a set of Arabic language localization protocols, along with standard operating procedures.     

HbA1c in pregnancy

During pregnancy, the glucose levels vary according to the hormonal changes and the metabolic needs necessary to maintain fetal nutrition but strict glycemic control is essential to minimize the maternal and fetal morbidity and mortality of pregnancies complicated by diabetes. Although considered the “gold standard” for diagnosis, measurement of glucose in the blood is subject to several limitations, many of which are not widely appreciated. Measurement of A1c for diagnosis is appealing as with one number, a total, integrated view of glycemia over time is derived though it has some inherent limitations. Thus, supplementation with HbA1c, as is common outside pregnancy, seems appropriate. Before pregnancy, the target for metabolic control in women with diabetes is HbA1c values near the normal range. However, the upper normal range of HbA1c during normal pregnancy is only sparsely investigated with different methods though recently a number of papers have been published regarding the determination of reference ranges for HbA1c in pregnancy. These changes may have clinical implications for the assessment and management of glycemic control in diabetic pregnancy and calls for establishment of separate reference limits of HbA1c levels in different trimesters as compared to general population.