Memory of Chirality in the Electrochemical Oxidation of N-o-Phenylbenzoylated Prolinols

Memory of chirality in electrochemical carbon-carbon bond cleavage of N-o-phenylbenzoylated (S)-prolinol derivatives was observed. Substituents of the α-position affected the ee of the products. The reaction of α,α-diarylated (S)-prolinol derivatives proceeded smoothly to afford optically active α-methoxylated pyrrolidine with up to 73% ee

Study of human adult parotid duct in the area of penetration through buccinator muscle and their functional relationship as a sphincter

The adult human parotid duct is roughly 6-8 cm long. From the parotid gland, parotid duct traverses through masseter muscle, penetrates through buccinator muscle, and opens into the oral cavity. This unique form of the parotid duct is likely correlated with the function of the duct, directly affected by the movement of the buccinator muscle during mastication and swallowing. Histological structure of the duct is known to be different in each region, and details of smooth muscle present in the parotid duct are mostly unclear. In this study, we conducted SEM and histological observations of the area where the parotid duct penetrates the buccinator muscle, and an observation of smooth muscle to investigate its existence using α-smooth muscle antibody. We confirmed the presence of an abundance of skeletal muscle bundles likely originating from the buccinator muscle under the epithelium of the parotid duct wall in the region where it penetrates the buccinator muscle. We also observed that some of the muscle fibers were completely attached to the epithelium. We observed a lack of smooth muscle in this region of the duct wall. From these results, we suggest that the area of the duct penetrating buccinator muscle plays a role in regulating the salivary passage through the contraction of the surrounding buccinator muscle fibers

Morphological study of the parotid duct in human fetuses with special emphasis on the relationship between the buccinator muscle and the parotid duct

Parotid glands secrete about 25% of all saliva produced in the salivary glands. In the presence of a stimulus, the amount of saliva secreted from the parotid gland increases to 50% (1). In human adults, the parotid duct, approximately 6-8 cm long, traverses the masseter muscle and penetrates through the buccinator muscle into the oral cavity. Although various studies have been conducted on the parotid gland, there are only few suggesting the functional roles of the parotid duct, especially of the area penetrating the buccinator muscle. In the present study, we observed parotid ducts of human fetuses to morphologically analyze the function of the buccinator muscles in the flux of parotid saliva. Thirty fetal specimens ranging from five to ten months of age were dissected for anatomical and histological examinations. The area of the parotid duct penetrating the buccinator muscle was fully formed in six-month-old fetuses. Furthermore, this study confirms the existence of thin buccinator muscle fibers underneath the epithelium of the parotid duct’s distal portion. Results suggest that the buccinator muscle may play a major role in preventing the reflux of salivary secretions by assisting the contraction of the parotid duct

Distribution and roles of substance P in human parotid duct

Sialadenitis occurs with greatest frequency in the parotid glands because infection and inflammation arise easily from the oral cavity. Since patients often experience severe swelling and pain during inflammation, the distribution of sensory nerves in these ducts may have clinical significance. We used antibodies to the known neuropeptide substance P and to tyrosine hydroxylase - a marker of adrenergic fibres - to observe their distribution and gain insight on their functional role in adult human parotid duct. After excising the parotid duct along with the gland, specimens were divided into three regions: the tract adjacent to the parotid gland, the route along the anterior surface of the masseter, and the area where the duct penetrates the buccinator muscle and opens into the oral cavity. Specimens were prepared and examined under a fluorescence microscope following immunostaining. Substance P positivity was observed in all three regions of the duct, whereas tyrosine hydroxylase was distributed mainly in the vascular walls and surrounding areas. The distribution of substance P candidates this molecule to assist in tissue defense in conjunction with the blood and lymph vessels of this area. Tyrosine hydroxylase in the blood vessel wall likely contributes to regulation of blood flow in concert with substance P positive nerves surrounding the blood vessels

Memory of Chirality in the Electrochemical Oxidation of Thiazolidine-4-carboxylic Acid Derivatives

Memory of chirality in the electrochemical oxidation of thiazolidine-4-carboxylic acid derivatives was observed. The relatively larger size of sulphur atom than the oxygen atom for oxazolidine-4-carboxylic acid derivative may slightly improved the enantioselectivities of the oxidized products. The bulkier penicillamine derivative 1c furnished 2c with much better enantioselectivity (91% ee) than that of the cysteine derivative 2b (85% ee). The presence of two extra dimethyl groups, for the penicillamine derivative improved the enantioselectivities of the thiazolidine derivatives from 85% ee to 91 % ee

Continuum of vasodilator stress from rest to contrast medium to adenosine hyperemia for fractional flow reserve assessment

Objectives: This study compared the diagnostic performance with adenosine-derived fractional flow reserve (FFR) ≤0.8 of contrast-based FFR (cFFR), resting distal pressure (Pd)/aortic pressure (Pa), and the instantaneous wave-free ratio (iFR). Background: FFR objectively identifies lesions that benefit from medical therapy versus revascularization. However, FFR requires maximal vasodilation, usually achieved with adenosine. Radiographic contrast injection causes submaximal coronary hyperemia. Therefore, intracoronary contrast could provide an easy and inexpensive tool for predicting FFR. Methods: We recruited patients undergoing routine FFR assessment and made paired, repeated measurements of all physiology metrics (Pd/Pa, iFR, cFFR, and FFR). Contrast medium and dose were per local practice, as was the dose of intracoronary adenosine. Operators were encouraged to perform both intracoronary and intravenous adenosine assessments and a final drift check to assess wire calibration. A central core lab analyzed blinded pressure tracings in a standardized fashion. Results: A total of 763 subjects were enrolled from 12 international centers. Contrast volume was 8 ± 2 ml per measurement, and 8 different contrast media were used. Repeated measurements of each metric showed a bias <0.005, but a lower SD (less variability) for cFFR than resting indexes. Although Pd/Pa and iFR demonstrated equivalent performance against FFR ≤0.8 (78.5% vs. 79.9% accuracy; p = 0.78; area under the receiver-operating characteristic curve: 0.875 vs. 0.881; p = 0.35), cFFR improved both metrics (85.8% accuracy and 0.930 area; p < 0.001 for each) with an optimal binary threshold of 0.83. A hybrid decision-making strategy using cFFR required adenosine less often than when based on either Pd/Pa or iFR. Conclusions: cFFR provides diagnostic performance superior to that of Pd/Pa or iFR for predicting FFR. For clinical scenarios or health care systems in which adenosine is contraindicated or prohibitively expensive, cFFR offers a universal technique to simplify invasive coronary physiological assessments. Yet FFR remains the reference standard for diagnostic certainty as even cFFR reached only ∼85% agreement

The multi-modality cardiac imaging approach to the Athlete's heart: an expert consensus of the European Association of Cardiovascular Imaging

The term 'athlete's heart' refers to a clinical picture characterized by a slow heart rate and enlargement of the heart. A multi-modality imaging approach to the athlete's heart aims to differentiate physiological changes due to intensive training in the athlete's heart from serious cardiac diseases with similar morphological features. Imaging assessment of the athlete's heart should begin with a thorough echocardiographic examination. Left ventricular (LV) wall thickness by echocardiography can contribute to the distinction between athlete's LV hypertrophy and hypertrophic cardiomyopathy (HCM). LV end-diastolic diameter becomes larger (>55 mm) than the normal limits only in end-stage HCM patients when the LV ejection fraction is <50%. Patients with HCM also show early impairment of LV diastolic function, whereas athletes have normal diastolic function. When echocardiography cannot provide a clear differential diagnosis, cardiac magnetic resonance (CMR) imaging should be performed. With CMR, accurate morphological and functional assessment can be made. Tissue characterization by late gadolinium enhancement may show a distinctive, non-ischaemic pattern in HCM and a variety of other myocardial conditions such as idiopathic dilated cardiomyopathy or myocarditis. The work-up of athletes with suspected coronary artery disease should start with an exercise ECG. In athletes with inconclusive exercise ECG results, exercise stress echocardiography should be considered. Nuclear cardiology techniques, coronary cardiac tomography (CCT) and/or CMR may be performed in selected cases. Owing to radiation exposure and the young age of most athletes, the use of CCT and nuclear cardiology techniques should be restricted to athletes with unclear stress echocardiography or CMR

Developing energy efficient lignin biomass processing: towards understanding mediator behaviour in ionic liquids

Environmental concerns have brought attention to the requirement for more efficient and renewable processes for chemicals production. Lignin is the second most abundant natural polymer, and might serve as a sustainable resource for manufacturing fuels and aromatic derivatives for the chemicals industry after being depolymerised. In this work, the mediator 2,2′-azino-bis(3-ethylbenthiazoline-6-sulfonic acid) diammonium salt (ABTS), commonly used with enzyme degradation systems, has been evaluated by means of cyclic voltammetry (CV) for enhancing the oxidation of the non-phenolic lignin model compound veratryl alcohol and three types of lignin (organosolv, Kraft and lignosulfonate) in the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate, ([C2mim][C2SO4]). The presence of either veratryl alcohol or organosolv lignin increased the second oxidation peak of ABTS under select conditions, indicating the ABTS-mediated oxidation of these molecules at high potentials in [C2mim][C2SO4]. Furthermore, CV was applied as a quick and efficient way to explore the impact of water in the ABTS-mediated oxidation of both organosolv and lignosulfonate lignin. Higher catalytic efficiencies of ABTS were observed for lignosulfonate solutions either in sodium acetate buffer or when [C2mim][C2SO4] (15 v/v%) was present in the buffer solution, whilst there was no change found in the catalytic efficiency of ABTS in [C2mim][C2SO4]–lignosulfonate mixtures relative to ABTS alone. In contrast, organosolv showed an initial increase in oxidation, followed by a significant decrease on increasing the water content of a [C2mim][C2SO4] solution

Human Skin/SCID Mouse Chimeras as an In Vivo Model for Human Cutaneous Mast Cell Hyperplasia

Human skin xenografted to mice with severe combined immunodeficiency syndrome (SCID) was evaluated to determine the integrity and fate of human dermal mast cells. There was an approximately 3-fold increase in number of dermal mast cells by 3 mo after engraftment (p < 0.05). These cells were responsive to conventional mast cell secretagogues and were confirmed to be of human origin by ultrastructural characterization of granule substructure and by reactivity for the human mast cell proteinase, chymase. CD1a+ Langerhans cells, also bone marrow–derived cells, failed to show evidence of concomitant hyperplasia, and increased mast cell number was not associated with alterations in number of dermal vascular profiles identified immunohistochemically for human CD31. RT-PCR analysis demonstrated human but not murine stem cell factor (SCF; also termed mast cell growth factor, c-kit ligand) mRNA in xenografts. Epidermal reactivity for stem cell factor protein shifted from a cytoplasmic pattern to an intercellular pattern by 3 mo after engraftment, suggesting a secretory phenotype, as previously documented for human cutaneous mastocytosis. The majority (>90%) of mast cells demonstrated membrane reactivity for human SCF at the time points of peak hyperplasia. These data establish SCID mouse recipients of human skin xenografts as a potential in vivo model for cutaneous mast cell hyperplasia