3,114 research outputs found
New electron microscope employs new video display technique
Video display system for a scanning electron microscope provides slow scanning rates, a self-generated color gradient technique, and allows leisurely viewing of several hours. It also enables the viewing of areas where selected energy regions contribute relatively few electrons, and the changing of specimen position and magnification without adjustments
Tropical sprue: a discussion of the aetiology, diagnosis and treatment with a description of nine personal cases treated with folic acid
The problems presented by sprue have been discussed and the conclusions arrived at are set down
under the headings of the various sections of this
thesis.1. THE PHYSIOLOGY OF NORMAL FAT ABSORPTION.
(a) VERZAR and McDOUGALL'S partition theory of
fat absorption is discussed in the light of FRAZER'S
investigations, which show that the partition theory
will not account for certain observations made by
himself and his fellow workers, chief of which is the
fact that fat can be demonstrated to be absorbed by
the intestinal cell in particulate and non hydrolysed
form.
(b) FRAZER'S work has been extensively quoted
and described in full. His findings point to the
conclusion that the failure to absorb fat in sprue
is dependant on a breakdown of the process in the
intra cellular phase and that the fault probably is
to be found in the process of phosphorylation.
(c) FRAZER'S findings suggest that absorption
of triglycerides and of fatty acids occurs by
different routes, the triglyceride being absorbed by
the lacteals into the systemic circulation whereas
the fatty acids appear to be absorbed into the
portal circulation and thence pass to the liver.2. THE BIOCHEMICAL CHANGES IN SPRUE.
(a) Absorption defects occur in sprue which
affect many dietary constituents and are not limited
to fat alone.
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(b) The fallacy of assessing fat excretion
by determining the faecal fat in a single stool
specimen is stated: the importance of putting the
patient on a known fat intake for at least two days
before doing a fat tolerance test and then estimating
the amount of fat excreted in the collected stools
of 2 to 5 days, in order to determine the percentage
of ingested fat which is excreted, is described.
Excretion of more than 10% of the ingested fat is
regarded as evidence of deficient absorption.
(c) The stools of cases of sprue are not
always of the typical bulky and frothy character:
they may be normal on cursory examination and, only
when examined by laboratory methods will steatorrhoea
be discovered. The watery diarrhoea which may
occur in cases of sprue is described: it responds
to sulphaguanidine and therefore may be mistaken for
dysentery.
(d) The carbohydrate metabolism is discussed
and MAEGRAITH'S findings regarding the difference
between the absorption of glucose by mouth and intravenously are given and also the difference between
the absorption of glucose and of fructose. The
typical "flat" glucose tolerance curve found in sprue
is described.
(e) The dehydration and changes in the blood
sodium chloride described by BLACK are noted, and
also the fact that sprue diets, which contain only
a normal salt content, require augmentation.3. THE AETIOLOGY OF SPRUE.
(a) The tendency to couple sprue with other
diseases such as pellagra and pernicious anaemia is
criticized and reasons for not regarding these diseases as being a series of overlapping clinical
conditions due to the same basic aetiological
factors are given.
(b) The theory that tropical sprue, coeliac
disease, idiopathic steatorrhoea and non tropical
sprue are essentially the same is discussed and it
is concluded that, in our present state of knowledge,
there is insufficient evidence for regarding these
conditions as having the same aetiology and, although
it is admitted that they all show biochemical similarities, the term "sprue" in this thesis is used to
refer to tropical sprue only.
(c) Certain facts regarding geographical
distribution, race, age and preceding infection are
stated as they appear to have a bearing on the
incidence of sprue.
(d) The condition of "Hill Diarrhoea" is
discussed. It is concluded that this condition is
often one of the modes of onset of sprue: if it is
not the precursor of recognisable sprue it is concluded that proper investigation of the cases will
reveal the cause of the diarrhoea. "Hill Diarrhoea"
is not admitted to be a disease entity.
(e) The work done during the past fifteen
years and the theories propounded are stated and
criticized.
STANNU.S'S theory that phosphorylation is dependent on catalysation by co- enzymes which catalyse
the phosphorylation of fats and polysaccharides, and
that these co- enzymes are identical for both, is
discussed.
It is concluded that, as cases of sprue often
show defective fat absorption but a normal glucose
tolerance curve, there is a difference between the
factors which affect the phosphorylation of fats and
sugars respectively.
(f) It is concluded that no evidence has been
established for regarding deficiency of the adrenal
cortex as an aetiological factor in sprue.
(g) The róle of vitamin deficiency in the
causation of sprue is discussed.
MANSON- BAHR'S theory that nicotinic acid and
riboflavine deficiency is responsible for the incidence of sprue is criticized. LEISHMAN'S theory
concerning interference with the biosynthesis of
vitamins in the intestine is discussed.
It is concluded that there is not sufficient
evidence to support the theory that deficiency of
the vitamin B2 complex is a fundamental factor in
the aetiology of sprue, with the exception of folic
acid, which, judged by the results of its administration, appears to replace a deficiency.
(h) DAVIDSON and GIRDWOOD'S conception of a liberating factor in the liver, deficiency of which
is responsible for the production of pernicious
anaemia, is described.
It is concluded that, in view of the inconstant
blood picture in untreated sprue and its variable
response to treatment, that deficiency of folic acid
or "liberating factor" is not an aetiological factor
in sprue, although it may play a part in the production of the blood picture in some cases.
(i) The enormous increase in the incidence of
sprue among our troops in India and the Far East
during the last war is contrasted with its virtual
non -occurrence among the prisoners -of -war in Japanese
hands.
These were living under identical or even
greater hardship. It is emphasized that these
prisoners did not develop signs of sprue when they
were repatriated and were taking a diet which contained a normal fat content.
The difference in the incidence of sprue between these two groups is attributed to the difference between the dietary fat intake of the two
groups and it is concluded that a certain intake of
fat is essential to the development of sprue and
that this is an essential aetiological factor.
(j) The type of fats in the diets of different races is considered and it is concluded that
the type of fat ingested in the diet may be an
aetiological factor of importance in sprue.
It is suggested that diets in which fats occur
mainly as vegetable oils may react differently to
the circumstances which produce sprue from diets in
which the fats are predominatingly of animal origin.4. THE DIAGNOSIS OF SPRUE.
(a) An effort has been made to confine the
condition of sprue within certain limits so that it
may be possible to define it clinically.
Therefore the clinical picture and differential
diagnosis have been set down. The finding of
steatorrhoea, which cannot be explained as being
secondary to any other pathological process, is considered an essential which must be present at some
phase in the course of the disease to warrant the
diagnosis being made.
(b) The X -ray findings in the intestine are
described and it is noted that these findings are
not confined to sprue but are seen in other deficiency syndromes. It is not considered justifiable to ascribe the dilatation of the colon to
bulkiness of the stools because this finding occurs
in cases which are in a state of clinical recovery
and whose stools are not bulky: it is suggested
that this dilatation of the colon must be due to
atony of the large intestine.
(c) The glucose tolerance curve, if flat in
character, is of value in confirming the diagnosis
of sprue but it is not exhibited in all cases.
(d) Loss of weight is an important sign of
active sprue: when the patient regains weight it
is considered to be a sign of remission and reestablishment of absorption from the gut, although
a degree of steatorrhoea and anaemia may persist
after the body weight has returned to normal.
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(e) The blood picture is described and it is
noted that in some cases the blood changes are
normal or slight in degree.
(f) The differential diagnosis of sprue is
discussed.5. THE TREATMENT OF SPRUE.
(a) The treatment is described under sections
dealing with the general management, dietary treatment, vitamin therapy, liver therapy and treatment
with folic acid.
(b) The general principles of treatment are
stated and the importance of rest in bed and the
treatment of dehydration is stated.
(c) Graduated diets used in the Army are given
in Appendix No. 3.
(d) The use of vitamins other than Folic Acid
is not considered to be so important in the treatment of sprue as many workers believe. The main
indication for their use is to treat concomitant
vitamin deficiencies, such as scorbutic symptoms,
which may complicate sprue.
Other than this it is not considered necessary
to give vitamins, provided the diet is adequate in
them.
The fact that cases of sprue can be maintained
on yeast as described by BLACK and FOUBMAN is noted
but it is considered that this therapy has no advantage over a daily maintenance dose of 5 mgms. of
folic acid by mouth.
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(e) The results of liver therapy are discussed: crude extracts seem to be more beneficial
in sprue than are more refined extracts: it is also
noted that steatorrhoea may persist after general
clinical improvement and that the response of the
blood to liver therapy, even in cases which exhibit
macrocytic anaemia, is usually not so complete as is
the response in pernicious anaemia.
(f) The early work on folic acid and the results of the first clinical trials by SPIES, DARBY
et. al. are described. DAVIDSON and GIRDWOOD' S
conception of a "liberating factor" (L.F.) in the
liver which enables the liberation of free folic
acid from conjugated folic acid is discussed.
(g) Nine cases of sprue treated with folic
acid are tabulated and summarised.
It is noted that folic acid may produce clinical improvement in cases which have failed or ceased
to respond to liver therapy.
Folic acid causes rapid improvement in the
general condition but in some cases the steatorrhoea
does not revert to normal, though it may be improved,
and often the blood picture cannot be restored to
normal completely.
(h) It is considered that larger doses of
folic acid are necessary for the treatment of sprue
than for the treatment of pernicious anaemia and
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that maintenance therapy may be required for some
time in order to retain the health recovered.
(i) The action of folic acid in reducing the
fluid in the stool is not understood. It is concluded that it must perform this by affecting the
absorption of fluid from the large intestine.
(j) It is considered that the use of folic
acid represents an important advance in the treatment of sprue and that it should be used in all
cases if available
Challenging the empire
This paper considers how Paul Gilroy transformed hitherto dominant understandings of the relationship between race and class by developing an innovative account that foregrounded questions of racist oppression and collective resistance amid the organic crisis of British capitalism. The returns from this rethinking were profound in that he was able to make transparent both the structuring power of racism within the working class, and the necessity for autonomous black resistance. At the same time, significant lacunae in his account are identified, including the neglect of the episodic emergence of working-class anti-racism and the part played by socialists, particularly those of racialized minority descent in fashioning a major anti-racist social movement. The paper concludes with a lament for the disappearance of such work informed by a ‘Marxism without guarantees’ in the contemporary field of racism studies, and asks readers to consider the gains to be derived from such a re-engagement
The organic crisis of British capitalism and race: the experience of the seventies
Chapter 1 of the "Empire Strikes Back" examines the place of "race" and racism in the political transformation of Britain at the end of the 1970s, and argues that Britain has entered a long-term political and economic crisis which has brought new urgency to the politics of race and nation. The authors argue that the British state is very far from its popular image as a liberal democracy, and all our notions of culture, nation and class are based on deeply racist structures
Racism and anti-racism in Europe: a critical analysis of concepts and frameworks
The targets and expressions of racism vary across Europe. This article discusses the relevance of different descriptions and analyses of racism despite the different terms used in different countries such as ‘ethnic minority’, ‘foreigner’ or ‘black’ and different interpretations of which differences matter. It shows the significance of a cross-national European perspective on racism. There are important convergences across European countries in the discourses and practices of racism, particularly the distinction between ‘useful’ and ‘abusive’ migrants. A cross-European perspective can be an important inspiration for anti-racist struggles
Environmentally Conscious Manufacturing Through Total Cost Management
Total Cost Management (TCM) is a business paradigm for managing all company resources and the activities that consume those resources with a focus on stimulating and managing improvements. We address the theoretical approach of TCM to environmental sustainability and present a practical case of using costing approaches to evaluate the sustainability of the manufacture of a recycled product. Decision aids, the QFD matrix, B2B e-commerce, allowable costs, and market-based pricing are employed to demonstrate that companies can apply the TCM model to integrate environmental policy as an essential component of corporate strategy to achieve and maintain competitive superiority
Affect - an ethnocentric encounter?: Exploring the 'universalist' imperative of emotional/affectual geographies
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