Humours

The vitreous is a transparent extracellular matrix occupying the space between the posterior lens and the retina and, in the majority of vertebrate species, constitutes the major f)art of the volume of the eye. Embryo-logically it can be considered as the basement membrane of the retina. It provides a mechanical support for surrounding tissues and acts as a shock absorber by virtue of its viscoelastic properties (Balzas and Delinger, 1984). Vitreous consists mainly of water (98%) and colloids (0.1%) with ions and low molecular weight solutes making up the remainder. It is not fully developed at birth, and changes in both volume and chemical composition occur postnatally. 

The mature vitreous contains a class of mononuclear phagocytic cells called hyalocytes (Balzas and Delinger, 1984). These cells are generally embedded in the vitreous humour 20-50 /tM away from the basal lamina, forming a single layer of scattered cells. In the developing eye they are located more centrally and are capable of synthesizing the main solid constituents of the vitreous gel. 

Hyaluronic acid and collagen are the two main structural components. The collagen is similar to that found in cartilage, consisting of three alpha-chains and known as type II collagen, although subtle differences are now recognized (Swann and Constable, 1972 Swann, 1980). 

Random collagen fibres provide an insoluble gel-like primary network and polyanionic hyaluronic acid a secondary network, which confers the viscoelastic property and stabilizes the collagen network (Balzas and Delinger, 1984). 

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Florfenicol concentrations in the brain, cerebrospinal fluid (CSF), and aqueous humor were one-fourth to one-half the corresponding semm concentrations. Concentrations in these tissues and fluids did not decrease as rapidly, maintaining a low, but fairly constant value. Because the brain, CSF, and aqueous humour are separated from the blood by specialized barriers, florfenicol can seemingly only cross these barriers to a limited extent. 

Nine years later, the Zeitschrift fur physikalische Chemie was followed by the Journal of Physical Chemistry, founded in the USA by Wilder Bancroft (1867-1953), one of Ostwald s American students. The chequered career of this journal is instructively analysed by both Laidler (1993) and Servos (1990). Bancroft (who spent more than half a century at Cornell University) seems to have been a difficult man, with an eccentric sense of humour thus at a Ph.D. oral examination he asked the candidate What in water puts out fires , and after rejecting some of the answers the student gave with increasing desperation, Bancroft revealed that the right answer was a fireboat . Any scientific author will recognize that this is not the ideal way for a journal editor to behave, let alone an examiner. There is no space here to go into the vagaries of Bancroft s personality (Laidler can be consulted about this), but... 

Fingerprinting the Hyaluronic Acid-Protein Complex of Human Vitreous Humour, S. A. Barker, S. J. Crews, J. B. Marsters, and M. Stacey, Clin. Chim. Acta, 11 (1965) 139-145. 

Christ in glory was the proto-type for perfected human flesh. This idea parallels the Galenic theory of balancing the bodily humours in a perfectly tempered body. Schwenckfeld, however, did not envisage perfection in these medical terms, but in that of an immortal body, divinely illuminated by Christ s sacrifice. The existence of Christ s glorified, but human body on earth testified that humans are not in essence natural bodies, but that their true form is that of Christ. In this argument, Schwenckfeld was relying on Paul s problematic account of the risen body. ... 

The earliest uses of microorganisms to treat human disease can be traced to the belief that formation of pus in some way drained off noxious humours responsible for systemic conditions. Although the spontaneous appearance of pus in their patients wounds satisfied most physicians, deliberate contamination of wounds was also practised. Bizarre concoctions of bacteria such as ointment of pigs dung and herb sclerata were favoured during the Middle Ages. Both early central European and South... 

The cornea is the first structure of the eye to be in contact with incident light. It is composed of five distinct layers lying parallel to its surface the outer epithelium, which is continuous with the epithelial layers of the conjunctiva the epithelial basal lamina the keratocyte-containing stroma, which is a collagen structure arranged so that it is transparent Descemet s membrane and, finally, the endothelium adjacent to the aqueous humour. 

Since the cornea derives its eneigy from the breakdown of glycogen and glucose, it requires oxygen, which it derives from the atmosphere, the tears and from the aqueous humour. A high concentration of lactate is built up, which is eventually removed by passage into the aqueous humour. 

The intraocular pressure depends primarily on the rate of secretion of aqueous humour. The most notable con-stititutional difference between aqueous humour and blood plasma lies in their protein contents. Protein concentration in the aqueous is 5-15 mg/100 ml, and that of the plasma is 1000-fold greater (6-7 g/100 ml). However, all the plasma proteins are present in aqueous humour - albeit at very low concentrations, therefore it is... 

Hydrogen peroxide is present in normal aqueous (approximately 30 /imol/1) whilst mean concentrations of around 70 tmol/l have been reported in aqueous from patients with cataracts, supporting a role for oxidative damage in the formation of cataracts (Spector and Garner, 1981). Diamine oxidase is one of the few enzymes to have been detected in bovine aqueous humour (albeit in trace quantities). It has been su ested that the hydrogen peroxide present in aqueous may be the product of the oxidative deamination of diamine substrates. This hypothesis is still unproven, since diamine oxidase substrates have not been identified in aqueous humour. 

GSHPx, CAT and SOD, which normally protect cells from free-radical damage have not been detected in aqueous humour. It has therefore been su ested that damage by free radicals and hydrogen peroxide to the anterior segment is prevented by a non-enzymatic extracellular oxidoreduction system involving a constant supply of reduced glutathione to the aqueous fluid from the ciliary epithelium, cornea and lens (Riley, 1983). 

Read, John. Humour and humanism in chemistry. London G. Bell, 1947. xxiii, 388p. 

Maybe. ",..[A]n epic poem on plant humours, an abstruse alchemical treatise, an experiential narrative jigsaw puzzle, a hip and learned wild-natured reference text, a... 

Jonson, Ben.Jonson Every man in his humour and The alchemist a casebook / edited by R. V. Holdsworth. Edited by Roger Victor Holdsworth. London Macmillan, 1978. 244p. 

The editors have done their bit the publishers have done their bit by making the data available in book form and on CD-ROM. It is now up to you. As a bonus you will find the data fascinating to browse through, you will come across many facts that you never knew before, or had forgotten, and you will be amused by the deadpan humour of a few entries such as those on air, environmentalism, safety literature, sunspots and superiors. 

Stanley Shostak I m reminded of Huxley s response to Wilberforce. You ve used your enormous intellect to reduce the subject to humour. I object, and I think we have a very serious crisis in our culture, and while we might find it amusing it s going to be devastating unless we have an alternative. So let me be reductionist for a moment and remind you that in Code of Codes Watson explains that he appealed to Congress for support because he knew that the politicians wanted to be able to advertise that they... 

Dorothy Nelkin Well, first of all as a social scientist I feel that humour is serious. It is also a pedagogical device to get people to listen at the end of a long meeting. Studies of the sociology and psychology of humour suggests that it s serious, as social commentary and an indication of public attitudes. 

Dorothy Nelkin Is there a gene for humour There s a gene for happiness - there must be one for humour. You know the only way I can figure out how to counter the impact of reductionism is to make people aware of the absurdity of what is happening, because certain assumptions become so embedded in culture and the way we think about things that they are not raised to the level of consciousness. Once people are aware then there s hope of thinking more seriously about the policy consequences. 

First of all I want to thank Prof. Dr. Gerhard Lammel for guiding me through the entire time with well-balanced motivation and criticism, specific questions, and good-humoured advice, and for giving me the freedom to shape my selfmotivation and independence. 

The Gibbs function G is named after Josiah Willard Gibbs (1839-1903), a humble American who contributed to most areas of physical chemistry. He also had a delightful sense of humour A mathematician may say anything he pleases, but a physicist must be at least partially sane. ... 

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