4,445 research outputs found
Reflections on nephritis
A brief resume of the pathological aspect of
Bright's disease is given. The interpretation
usually put on the pathological findings is that the
various types of Bright's disease represent different
stages of one continuous process which is initiated
by the primary glomerular lesions in the first or
acute stage. hence the use of the terms first, second
and third stage nephritis. The continuous process is
usually regarded as a progressive degeneration of the
renal elements brought about by the obstruction to
blood flow through the glomeruli.
The clinical course of Bright's disease is
briefly reviewed. It is pointed out that only a
minority of cases pass through the three stages or
types. Subacute or "second stage" nephritis is often
encountered apparently arising independently. The
explanation of this phenomenon by assuming a preexisting
"subclinical" acute nephritis is discussed.
The functioning power of the kidneys in the three
stages or types of Bright's disease is described.
It is pointed out that acute glomerulo- nephritis and
chronic glomerulo- nephritis are associated with
impairment of excretion of nitrogenous end products
by the kidneys and that the blood pressure is raised,
while in subacute glomerulo- nephritis excretion of
nitrogenous end products is adequate, and the blood
pressure is normal.
An investigation is described which attempts to
establish the presence or absence of a "subclinical"
acute glomerulo- nephritis. The limitations of the
investigation are pointed out. No evidence was found
to favour the presence of such an entity.
The view that Bright's disease is a condition
which inevitably progresses from the acute stage
through the subacute to the chronic stage, or ends
in cure after the acute or subacute stage, is criticised.
It is pointed out that the fact that renal
function improves when a case passes from the acute
to the subacute type is not in keeping with the view
that the change is due to a further progression of
damage to the nephrons initiated in the acute phase.
That the tubular degeneration which is so marked in
subacute glomerulo-nephritis, is due to vascular
obstruction of the glomeruli is shown to be false. It is
demonstrated that the tubules have their own direct
blood supply which is quite adequate even although
glomerular circulation is abolished entirely. If the
acute stage initiates a chain of events which leads
inevitably to a small granular kidney with failing
function, why do not all cases show this progression?
A point is made of the fact that the glomerulitis
seen in Bright's disease is not pathognomonic for
that condition. It is a non -specific response which
can result from a variety of stimuli or toxins of
varying intensity. Such glomerular changes are seen
in focal embolic nephritis, syphilitic nephritis, in
diphtheria and typhoid etc. That tubular degeneration
can occur with little or nothing in the way of coincident
glomerular changes is evidenced by such conditions
as lipoid nephrosis, nephroses due to chemical
irritants etc.
An alternative view is suggested. The micro -
pathology of the various types of Bright's disease
are regarded as reactions which vary in tempo in
accordance with the intensity of the irritant, so
that acute, subacute, and to some extent chronic, reactions
take place. The similarity between the process
and that which occurs in acute, subacute yellow
atrophy, and healed yellow atrophy of the liver is
mentioned. In this way cases of acute and subacute
glomerulo-nephritis can arise de novo. It is suggested
that the response evoked in the kidney (the
type of nephritis) depends on the intensity of the
circulating toxin. The toxin may be the same for all
types of Bright's disease or may differ. Chronic
focal sepsis would appear to play a part in the
aetiology of some cases of subacute glomerulo-nephritis.
The method by which the toxin intensity may vary
is discussed. Partial breakdown of immunity mechanism
is suggested as a cause, and is linked with the low
blood complement and proteins observed in some cases
of nephritis.
The possibility of aglomerular tubular function
in sub -acute and chronic glomerulo- nephritis is
mentioned. This is not regarded as being the sole
mechanism by which the kidneys function but may well
play an important part.
From these reflections it is felt that the
"accepted view" rests on very slender evidence,
namely, that some cases do progress through the
various stages, and that the glomerular changes can
be traced through these stages. As we have seen
there is nothing pathognomonic about "glomerulitis".
It can result from a variety of causes.
The known facts would appear to be explained by
the alternative view more satisfactorily. The evidence
suggests that subacute nephritis is due to a
toxin of less intensity than is encountered in acute
nephritis, and as such may arise independently or
follow an acute attack. Chronic glomerulo- nephritis
is probably a stage of healing with perhaps some mild
irritant action superimposed, and is therefore a
sequence of repeated attacks of acute glomerulonephritis,
or of subacute glomerulo-nephritis.
The necessity for more numerous and extended
investigations into the question of "subclinical
nephritis" is appreciated
SBMS: A Visual Exploration of Liberian Identity
This article explores the use of visuals by missionaries and social scientists to communicate their encounters in sub-Saharan Africa. It offers an alternative perspective by incorporating the Sight Beyond My Sight (SBMS) visual research methodology created by Gabriel Tait. SBMS is a participant research method that employs photography as a way to understand culture and identity. The implications of this body of work, and the method it provides, presents a much-needed contextual lens for missionaries, visual ethnographers, and general persons who are interested in communicating their contexts in partnership with the cultures they are encountering and impacting. The implication of this work is a more accurate representation of the identities of the people they are working alongside
Gamma-ray lines and One-Loop Continuum from s-channel Dark Matter Annihilations
The era of indirect detection searches for dark matter has begun, with the
sensitivities of gamma-ray detectors now approaching the parameter space
relevant for weakly interacting massive particles. In particular, gamma ray
lines would be smoking gun signatures of dark matter annihilation, although
they are typically suppressed compared to the continuum. In this paper, we pay
particular attention to the 1-loop continuum generated together with the
gamma-ray lines and investigate under which conditions a dark matter model can
naturally lead to a line signal that is relatively enhanced. We study generic
classes of models in which DM is a fermion that annihilates through an
s-channel mediator which is either a vector or scalar and identify the coupling
and mass conditions under which large line signals occur. We focus on the
"forbidden channel mechanism" advocated a few years ago in the "Higgs in space"
scenario for which tree level annihilation is kinematically forbidden today.
Detailed calculations of all 1-loop annihilation channels are provided. We
single out very simple models with a large line over continuum ratio and
present general predictions for a large range of WIMP masses that are relevant
not only for Fermi and Hess II but also for the next generation of telescopes
such as CTA and Gamma-400. Constraints from the relic abundance, direct
detection and collider bounds are also discussed.Comment: 32 pages, 13 figures; v2: minor clarifications, summary paragraph
added; v3: matches published version, minor clarifications, results unchange
Conserved Currents are Not Anomaly-Safe
New vector bosons that are coupled to conserved currents in the Standard
Model exhibit enhanced rates below the electroweak scale from anomalous
triangle amplitudes, leading to (energy/vector mass) enhancements to rare Z
decays and flavor-changing meson decays into the longitudinally polarized
vector boson. In the case of a vector boson gauging , the mass gap
between the top quark and the remaining SM fermions leads to (energy/vector
mass) enhancements for processes with momentum transfer below the top mass.
In addition, we examine the case of an intergenerational
that has been proposed to resolve the anomaly with an MeV scale DM
candidate, and we find that these enhanced processes constrain the entire
parameter space.Comment: 19 pages, 4 figures, 1 tabl
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