Although fire is now rarely used in synthetic chemistry, it was not until Robert Bunsen invented the burner in 1855 that the energy from this heat source could be applied to a reaction vessel in a focused manner. The Bunsen burner was later superseded by the isomantle, oil bath, or hot plate as a source for applying heat to a chemical reaction. In the past few years, heating and driving chemical reactions by microwave energy has been an increasingly popular theme in the scientific community. This nonclassical heating technique is slowly moving from a laboratory curiosity to an established technique that is heavily used in both academia and industry. The efficiency of "microwave flash heating" in dramatically reducing reaction times (from days and hours to minutes and seconds) is just one of the many advantages. This Review highlights recent applications of controlled microwave heating in modern organic synthesis, and discusses some of the underlying phenomena and issues involved.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.200400655

Controlled microwave heating in modern organic synthesis.

There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field. In this framework, a research finding is less likely to be true when the studies conducted in a field are smaller; when effect sizes are smaller; when there is a greater number and lesser preselection of tested relationships; where there is greater flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial and other interest and prejudice; and when more teams are involved in a scientific field in chase of statistical significance. Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias. In this essay, I discuss the implications of these problems for the conduct and interpretation of research.

Why most published research findings are false

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjogren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

TFOS DEWS II pathophysiology report

The tarsal glands of Meibom (glandulae tarsales) are large sebaceous glands located in the eyelids and, unlike those of the skin, are unassociated with hairs. According to Duke-Elder and Wyler,1 they were first mentioned by Galenus in 200 AD and later, in 1666, they were described in more detail by the German physician and anatomist Heinrich Meibom, after whom they are named.

Lipids produced by the meibomian glands are the main component of the superficial lipid layer of the tear film that protects it against evaporation of the aqueous phase and is believed also to stabilize the tear film by lowering surface tension.2 Hence, meibomian lipids are essential for the maintenance of ocular surface health and integrity.

Although they share certain principal characteristics with ordinary sebaceous glands, they have several distinct differences in anatomy, location, secretory regulation, composition of their secretory product, and function.

Functional disorders of the meibomian glands, referred to today as meibomian gland dysfunction (MGD),3 are increasingly recognized as a discrete disease entity.4–8 In patients with dry eye disease, alterations in the lipid phase that point to MGD are reportedly more frequent than isolated alterations in the aqueous phase. In a study by Heiligenhaus et al.,9 a lipid deficiency occurred in 76.7% of dry eye patients compared with only 11.1% of those with isolated alterations of the aqueous phase. This result is in line with the observations by Shimazaki et al.10 of a prevalence of MGD in the absolute majority of eyes with ocular discomfort defined as dry eye symptoms. These observations noted that 64.6% of all such eyes and 74.5% of those excluding a deficiency of aqueous tear secretion were found to have obstructive MGD, or a loss of glandular tissue, or both.10 Horwath-Winter et al.11 reported MGD in 78% of dry eye patients or, if only non-Sjogren patients are considered, in 87% compared with 13% with isolated aqueous tear deficiency. It may thus be accepted that MGD is important, conceivably underestimated, and possibly the most frequent cause of dry eye disease due to increased evaporation of the aqueous tears.5,9–12

After some excellent reviews of MGD4,7,8,13,14 in the past, many new findings have been reported in recent years, and other questions remain to be identified and resolved. A sound understanding of meibomian gland structure and function and its role in the functional anatomy of the ocular surface15 is needed, to understand the contribution of the meibomian glands to dysfunction and disease. Herein, we seek to provide a comprehensive review of physiological and pathophysiological aspects of the meibomian glands.

/pdf/the-international-workshop-on-meibomian-gland-dysfunction-1rohh1kg6i.pdf

The International Workshop on Meibomian Gland Dysfunction: Report of the Subcommittee on Anatomy, Physiology, and Pathophysiology of the Meibomian Gland

The members of the Management and Therapy Subcommittee undertook an evidence-based review of current dry eye therapies and management options. Management options reviewed in detail included treatments for tear insufficiency and lid abnormalities, as well as anti-inflammatory medications, surgical approaches, dietary modifications, environmental considerations and complementary therapies. Following this extensive review it became clear that many of the treatments available for the management of dry eye disease lack the necessary Level 1 evidence to support their recommendation, often due to a lack of appropriate masking, randomization or controls and in some cases due to issues with selection bias or inadequate sample size. Reflecting on all available evidence, a staged management algorithm was derived that presents a step-wise approach to implementing the various management and therapeutic options according to disease severity. While this exercise indicated that differentiating between aqueous-deficient and evaporative dry eye disease was critical in selecting the most appropriate management strategy, it also highlighted challenges, based on the limited evidence currently available, in predicting relative benefits of specific management options, in managing the two dry eye disease subtypes. Further evidence is required to support the introduction, and continued use, of many of the treatment options currently available to manage dry eye disease, as well as to inform appropriate treatment starting points and understand treatment specificity in relation to dry eye disease subtype.

TFOS DEWS II Management and Therapy Report

BACKGROUND In patients with nonarteritic anterior ischemic optic neuropathy (AION) we investigated the long-term effect of hemodilution on functional results, recurrence rate in the affected and involvement of the second eye. PATIENTS AND METHODS In a retrospective study we reviewed 24 patients ranging in age from 62 to 92 years (mean 77 years) with AION. The duration of follow-up was between 8-51 months (mean 24.8 months). All patients received iso- (Hct > 40%) or hypervolemic (Hct < or = 40%) hemodilution over 8-10 days with daily infusion of 10% hydroxyethyl-starch 200/0.5. The hematocrit decreased significant (p < 0.001) from 43.4 +/- 3.8% to 37.8 +/- 3.5% after this 10-day hemodilution treatment. RESULTS After the longterm follow-up 29.1% of the patients had an improvement of the central vision by two or more lines, 16.7% had a deterioration, 54.2% remained unchanged. The resulting visual acuity was between 0.5-1.0 in 37.5%, between 0.4-0.1 in 41.7% and worse than 0.1 in 20.8%. Neither visual fields nor the VECP were significant changed by hemodilution. After the mean follow-up period of 24.8 months no recurrence occurred in the affected eye and the second eye as never involved. CONCLUSION Hemodilution therapy has no significant longterm effect on visual acuity and visual fields, but it seems to have a beneficial influence on the recurrence rate in the affected and on the involvement of the second eye.

[Non-arteritic anterior ischemic optic neuropathy: long-term results after hemodilution therapy]

Hintergrund
Trotz der vielfaltigen Behandlungsmoglichkeiten bei trockenem Auge gibt es bisher keine Therapie, die eine vollstandige Heilung dieser Erkrankung ermoglicht Eine Erweiterung des Therapiespektrums stellt die Bespruhung der Augen von Patienten mit Keratokonjunktivitis sicca mit einer Ol-in-Wasser-Emulsion dar Die Wirkung dieser neuen Behandlungsmethode wurde untersucht

Eine neue Möglichkeit der Behandlung der Keratokonjunktivitis sicca durch Besprühung mit einer Öl-in-Wasser-Emulsion

Context: Contact with pollen is the major reason for the development of allergic symptoms on the ocular surface leading to a significant increase of allergic diseases worldwide. Environmental chang...

Decreased viability and proliferation of CHANG conjunctival epithelial cells after contact with ultraviolet light-irradiated pollen.

The reaction of o-aminophenylglyoxal dimethylacetales with sodium pyruvate in the presence of sodium ethoxide yields 4-dimethoxymethyl-quinoline-2-carboxylic acids which give the title compounds on acid hydrolysis.

Notizen: Zur Synthese von 4-Formyl-chinolin-2-carbonsäuren / Synthesis of 4-Formyl-quinoline-2-carboxylic Acids

Bei 97 Probanden mit normaler Harnsaurekonzentration im Serum (≤ 6,9 mg/dl) wurde die Konzentration der Harnsaure in der Tranenflussigkeit bestimmt und ein Mittelwert ± SD von 1,7 ± 0,8 mg/dl gemessen. Bei 36 Personen mit erhohten Serumharnsaurewerten (≥ 7,0 mg/dl) wurde der Harnsauregehalt in den Tranen mit 2,3 ± 1,0 mg/dl (Mittelwert ± SD) nachgewiesen. Die Harnsaurekonzentrationen in den Tranen beider Gruppen unterscheiden sich signifikant voneinander (p = 0,003). Zusatzlich findet sich eine signifikante Korrelation zwischen dem Harnsauregehalt in den Tranen und im Serum. Harnsaure stellt eine Substanz mit antioxidativer Aktivitat dar. Die gemessenen Harnsaurekonzentrationen in den Tranen lassen den Schluss zu, dass ein Teil des antioxidativen Status der Tranen auf den Gehalt an Harnsaure zuruckzufuhren ist.

Otto Schmut

Papers

[Non-arteritic anterior ischemic optic neuropathy: long-term results after hemodilution therapy]

Eine neue Möglichkeit der Behandlung der Keratokonjunktivitis sicca durch Besprühung mit einer Öl-in-Wasser-Emulsion

Decreased viability and proliferation of CHANG conjunctival epithelial cells after contact with ultraviolet light-irradiated pollen.

Notizen: Zur Synthese von 4-Formyl-chinolin-2-carbonsäuren / Synthesis of 4-Formyl-quinoline-2-carboxylic Acids

Quantitative Bestimmung von Harnsäure in menschlicher Tränenflüssigkeit