1,966 research outputs found
Congenital stenosis of the posterior urethra with resultant congenital bilateral hydronephrosis with dilation of the ureters and dilation and hypertrophy of the urinary bladde abdnd posterior urethra
1. The point at which the obstruction occurs is at the
junction of the Pars prostatica and the Pars
membranacea.2. No folds have been demonstrated at this point.3. A thickening of the muscular wall of the urethra
exists from this point backwards towards the
bladder.4. The folds or what may be taken as valve -like
structures when present, have developed from the
normally existing folds in the prostatic urethra and
in the drawing of the cases in literature can be
traced to their origin in the verumontanum. They
arise from the verumontanum either from its
anterior or posterior edge or from its middle.5. In some cases no folds exist and where they do, they
occur in those cases that have survived for some
time after birth. Only in one case have valves
been reported in a full time foetus.6. The folds are the result of mechanical pressure
exerted by the urine on the normal structures. In
this respect it is noted that mucous folds are
produced in the pylorus even where no folds
originally exist.7. The muscle hypertrophy is due to the over -action
caused by a want of harmony between the
parasympathetic and sympathetic systems of the
autonomic fibres either by direct action on the
muscle itself or on the vessels.8. In some cases other deformities are present as in
this case a deficiency and scarring of the anterior
abdominal wall above the pubis, probably due to
some action on the bloodvessels.9. Cure of the retention may be effected in early
cases by the passage of instruments causing
dilatation of the narrowed urethra similar to
Lorenze's operations for Congenital stricture of
the pylorus. But in later cases in which the
verumontanum flaps have developed, cutting of the
folds may be necessary.10. Analogous sites for a similar condition are found
in the
(1) Lower end of oesophagus.
(2) Pylorus.
(3) Lower end of Ileum.
(4) Rectum
The problem of the stethoscope: an enquiry, experimental and philosophical, into the properties of this instrument and the physics of auscultation
My interest in Stethoscopy dates back to the
time when I first entered the class of Clinical
Medicine. I had previously, while on war service,
been interested in the propagation of sound in
sea water, and finding that acoustics played so
important a part in the diagnosis of pulmonary and
cardiac conditions, I naturally sought to understand both the nature of intrathoracic vibratory
disturbances and the mechanism of their conveyance to the ear.In those early days two great difficulties
confronted me. Firstly, the difficulty of recognising the various pulmonary signs even when
directed what to listen for; secondly, the difficulty of following the explanations tendered for
the mechanism of their propagation and production.By the time I had finished my classes the
former had been partly overcome, the latter remained. And so, immediately after graduation I
found myself engrossed in the literature of auscultation. The more I read the more I became impressed with the need for greater scientific precision, so many of the observations amounting to
little more than mere impressions.As it seemed logical that we should first
endeavour to understand the mechanism of our
instruments, I was ultimately led to undertake
the work of this thesis, not relying merely upon
observations and impressions, but taking as my
guide the concepts and propositions framed chiefly
by those great master minds in sound and sound
sensation, Lord Rayleigh and Helmholtz.It is submitted that the reasoning, mathematical
demonstrations, and experiments of the thesis
warrant the following conclusions.(1) That the apprliation of the exact nature
of things with reference to the vibratory
behaviour both of the stethoscope and
of the tissues is a very complex problem.(2) That these articles demonstrate what
actually is involved in the problem.(3) That the few problems treated in more
detail, e.g. the subject of resonance
point to the hopelessness of anything
like an exact mathematical or physical
interpretation of the behaviour of the
instrument.(4) That there is a great need for exact
physical concepts both as regards the
behaviour of the stethoscope and the
thoracic structures e.g. that we should
drop the term conduction (or at least
restrict it to its proper physical connotation) and try to visualise the
stethoscope and its contained air, as
well as the corporeal structures, as
systems or bodies performing molar
vibrations and not as media in which
wave propagation takes place.(5) That owing to the variable relationship
between sound sensation and the external
physical disturbances to which they are
due, and owing to the manner in which
sound sensation can be modified by education and personal bias in virtue of
the subjective phenomena of analysis and
attention, the exact comparison of any
two instruments cannot be effected; and
having so far no experimental means of
recording and measuring faint sounds it
cannot be done by purely objective
means.(6 ) That the phenomena of selective resonance especially as attributable to the
behaviour of the stethoscope is hardly
ever observed. That it is not to be ex^
pected, because in the first place, the
majority of auscultation sounds cannot be
supposed capable of representation by a
periodic function, i.e. that they partake
more of th6 character of noises, and in
the second place, £he only frequency at
which selective resonance might occur
would be that corresponding to very close
isochronism with the gravest natural tone
of the air enclosed in the chest piece.(7) That what is usually designated selective
resonance on the part of the instrument
is not a magnification of a vibration
emenating from the body surface, but that
it is an adventitious element- a superimposed tonal mass of sound generated by
the enclosed air being set in vibration
by irregular disturbances as well as regular
and that it is related only in intensity
to the forcing vibrations.(8) That true bone conduction in stethoscopy
even in the monaural pattern is largely
a misnomer. That so called bone conduction is really the transmission of a
vibratory motion to the apparatus of the
middle ear by the meatus walls and hence
that the subsequent path, as in normal
hearing as via. the stapes and not as
in true bone conduction by the vibration
of the cochlear walls.That diaphragms cause a modification in the
sound in virtue of their own intrinsic
properties and do not merely serve the
purpose of preventing the encroachment
of the soft parts on the lumen of the
chest piece.That in the binaural instrument with rubber
tubes transmission by the column of air
is alone important. That the vibrations
of the column of air depends on the
variation in pressure in the air in the
chest piece» That the variation in
pressure in the air in the chest piece
is effected both by the vibrations of the
body surface and by rapid variations in
the configuration of the chest piece, and
that the best idea of the behaviour of
this mass of air is to be arrived at by
combining the fundamental concepts on which
the theory of resonators is framed with
the theory of stream lines in the motion of
fluids.That the guiding considerations on which
a binaural stethoscope should be designed
are these»Consideration should first be given to
the acoustics of the instrument,
secondly to the ease with which it can be
used, thirdly to portability.The part in contact with the body surface
should not be metal but a bad conductor
of heat.The actual shape of the chest piece is not
directly a matter of importance.The interposition of a diaphragm means further
modification of the original physical disturbances.The larger the area of body surface covered
the louder the sounds.The thinner and lightly and more highly
elastic (in the physical sense) the walls
of the chest piece and the smaller its
inertia, fee greater will be the contribution to the variation in pressure in the
air it encloses.The adventitious rumbling effeot of the air
chamber should be eliminated either by making
the chamber small or by breaking the apace
up by perforated diaphragms.The exit from the chest piece should be placed where the energy of motion is greatest.The air chamber should be deep enough to
allow the encroachment of the soft parts
within the lumen without producing any
appreciable dimin^ion in the energy of motion
in the vicinity of the exit.Rubber conducting tubes are an accepted necessity
because of their flexibility. Though flexible
metal means louder signals.The ear pieces must fit exactly and without
the slightest discomfort into the meatus and
the normal to the exit should be in the
direction of the meatus. This can be provided
for by the proper curving of the head tubes
and their union by a spring of suitable tension.finally that advance in stethoscopy depends
upon the introduction of an accessory source
of energy controlled to act as a relay probably
through the medium of the oscillation valve
Aspirin inhibits the acute venodilator response to furosemide in patients with chronic heart failure
OBJECTIVES:
We sought to determine the effect of aspirin on the venodilator effect of furosemide in patients with chronic heart failure (CHF)
BACKGROUND:
Furosemide has an acute venodilator effect preceding its diuretic action, which is blocked by nonsteroidal anti-inflammatory drugs. The ability of therapeutic doses of aspirin to block this effect of furosemide in patients with CHF has not been studied. For comparison, the venodilator response to nitroglycerin (NTG) was also studied.
METHODS:
Eleven patients with CHF were randomized to receive placebo, aspirin at 75 mg/day or aspirin at 300 mg/day for 14 days in a double-blind, crossover study. The effect of these pretreatments on the change in forearm venous capacitance (FVC) after 20 mg of intravenous furosemide was measured over 20 min by using venous occlusion plethysmography. In a second study, the effect of 400 μg of sublingual NTG on FVC was documented in 11 similar patients (nine participated in the first study).
RESULTS:
Mean arterial pressure, heart rate and forearm blood flow did not change in response to furosemide. After placebo pretreatment, furosemide caused an increase in FVC of 2.2% (95% confidence interval [CI] −0.9% to 5.2%; mean response over 20 min). By comparison, FVC fell by −1.1% (95% CI −4.2% to 1.9%) after pretreatment with aspirin at 75 mg/day, and by −3.7% (95% CI −6.8% to −0.7%) after aspirin at 300 mg/day (p = 0.020). In the second study, NTG increased FVC by 2.1% (95% CI −1.6% to 5.8%) (p = 0.95 vs. furosemide).
CONCLUSIONS:
In patients with CHF, venodilation occurs within minutes of the administration of intravenous dose of furosemide. Our observation that aspirin inhibits this effect further questions the use of aspirin in patients with CHF
The evolution of apolipoprotein B and its mRNA editing complex. Does the lack of editing contribute to hypertriglyceridemia?
The evolution of apolipoprotein B (Apob) has been intensely researched due to its importance during lipid transport. Mammalian full-length apob100 can be post-transcriptionally edited by the enzyme apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like complex-one (Apobec1) resulting in a truncated Apob, known as Apob48. Whilst both full-length and truncated forms of Apob are important for normal lipid homeostasis in mammals, there is no evidence for the presence of apob mRNA editing prior to the divergence of the mammals, yet, non-mammalian vertebrates appear to function normally with only Apob100. To date, the majority of the research carried out in non-mammalian vertebrates has focused on chickens with only a very limited number examining apob mRNA editing in fish. This study focused on the molecular evolution of Apobec1 and Apob in order to ascertain if apob mRNA editing occurs in eels, a basal teleost which represents an evolutionarily important animal group. No evidence for the presence of Apobec1 or the ability for eel apob to be edited was found. However, an important link between mutant mice and the evident hypertriglyceridemia in the plasma of non-mammalian vertebrates was made. This study has provided imperative evidence to help bridge the evolutionary gap between fish and mammals and provides further support for the lack of apob mRNA editing in non-mammalian vertebrates
Roles of histone deacetylases in epigenetic regulation: emerging paradigms from studies with inhibitors
The zinc-dependent mammalian histone deacetylase (HDAC) family comprises 11 enzymes, which have specific and critical functions in development and tissue homeostasis. Mounting evidence points to a link between misregulated HDAC activity and many oncologic and nononcologic diseases. Thus the development of HDAC inhibitors for therapeutic treatment garners a lot of interest from academic researchers and biotechnology entrepreneurs. Numerous studies of HDAC inhibitor specificities and molecular mechanisms of action are ongoing. In one of these studies, mass spectrometry was used to characterize the affinities and selectivities of HDAC inhibitors toward native HDAC multiprotein complexes in cell extracts. Such a novel approach reproduces in vivo molecular interactions more accurately than standard studies using purified proteins or protein domains as targets and could be very useful in the isolation of inhibitors with superior clinical efficacy and decreased toxicity compared to the ones presently tested or approved. HDAC inhibitor induced-transcriptional reprogramming, believed to contribute largely to their therapeutic benefits, is achieved through various and complex mechanisms not fully understood, including histone deacetylation, transcription factor or regulator (including HDAC1) deacetylation followed by chromatin remodeling and positive or negative outcome regarding transcription initiation. Although only a very low percentage of protein-coding genes are affected by the action of HDAC inhibitors, about 40% of noncoding microRNAs are upregulated or downregulated. Moreover, a whole new world of long noncoding RNAs is emerging, revealing a new class of potential targets for HDAC inhibition. HDAC inhibitors might also regulate transcription elongation and have been shown to impinge on alternative splicing
Water Footprint Differences of Producing Cultivars of Selected Crops in New Zealand
Water footprint (WF) is a measure of the amount of water used to produce goods and services. It is a very important concept on indicating how much water can be consumed to complete a process of growing or processing a product at a particular location. However, paucity of water footprint information in countries facing increased competition for water resources between industries limits market access and profit optimization. Water footprint differences of producing selected cultivars of potato, oca and pumpkin squash were determined under irrigation and rain-fed regimes. All crop husbandry practices were followed in potato, oca (3.3 plants m−2) and pumpkin squash (2.2 plants m−2). Water footprint was determined as the ratio of volume of evapotranspiration for irrigated and rain-fed crops plus grey water to total yield. The consumptive water use for the rain-fed crop was 75, 65 and 69% of the irrigated oca, potato and pumpkin squash, respectively, with high water consumption in heritage cultivars. The water footprint was low in pumpkin squash and highest in oca, while potato cultivars were intermediate. Irrigation reduced water footprint especially in crops more responsive to irrigation. Farmers should focus on improving the harvest index and irrigation to reduce water footprint
Effect of suspension systems on the physiological and psychological responses to sub-maximal biking on simulated smooth and bumpy tracks
The aim of this study was to compare the physiological and psychological responses of cyclists riding on a hard tail bicycle and on a full suspension bicycle. Twenty males participated in two series of tests. A test rig held the front axle of the bicycle steady while the rear wheel rotated against a heavy roller with bumps (or no bumps) on its surface. In the first series of tests, eight participants (age 19 – 27 years, body mass 65 – 82 kg) were tested on both the full suspension and hard tail bicycles with and without bumps fitted to the roller. The second series of test repeated the bump tests with a further six participants (age 22 – 31 years, body mass 74 – 94 kg) and also involved an investigation of familiarization effects with the final six participants (age 21 – 30 years, body mass 64 – 80 kg). Heart rate, oxygen consumption (VO<sub>2</sub>), rating of perceived exertion (RPE) and comfort were recorded during 10 min sub-maximal tests. Combined data for the bumps tests show that the full suspension bicycle was significantly different (P < 0.001) from the hard tail bicycle on all four measures. Oxygen consumption, heart rate and RPE were lower on average by 8.7 (s = 3.6) ml · kg<sup>-1</sup> · min<sup>-1</sup>, 32.1 (s = 12.1) beats · min<sup>-1</sup> and 2.6 (s = 2.0) units, respectively. Comfort scores were higher (better) on average by 1.9 (s = 0.8) units. For the no bumps tests, the only statistically significant difference (P = 0.008) was in VO<sub>2</sub>, which was lower for the hard tail bicycle by 2.2 (s = 1.7) ml · kg-1 · min<sup>-1</sup>. The results indicate that the full suspension bicycle provides a physiological and psychological advantage over the hard tail bicycle during simulated sub-maximal exercise on bumps
Flows driven by Banach space-valued rough paths
We show in this note how the machinery of C^1-approximate flows devised in
the work "Flows driven by rough paths", and applied there to reprove and extend
most of the results on Banach space-valued rough differential equations driven
by a finite dimensional rough path, can be used to deal with rough differential
equations driven by an infinite dimensional Banach space-valued weak geometric
Holder p-rough paths, for any p>2, giving back Lyons' theory in its full force
in a simple way.Comment: 8 page
Bacterial Communities of Ballan Wrasse (Labrus bergylta) Eggs at a Commercial Marine Hatchery
Ballan wrasse (Labrus bergylta, Ascanius 1767) are cleaner fish cultured in northern Europe to remove sea lice from farmed Atlantic salmon (Salmo salar, Linnaeus 1758). Despite increasing appreciation for the importance of the microbiota on the phenotypes of vertebrates including teleosts, the microbiota of wrasse eggs has yet to be described. Therefore, the aim of this present study was to describe the bacterial component of the microbiota of ballan wrasse eggs shortly after spawning and at 5 days, once the eggs had undergone a routine incubation protocol that included surface disinfection steps in a common holding tank. Triplicate egg samples were collected from each of three spawning tanks and analysis of 16S rRNA gene sequences revealed that 88.6% of reads could be identified to 186 taxonomic families. At Day 0, reads corresponding to members of the Vibrionaceae, Colwelliaceae and Rubritaleaceae families were detected at greatest relative abundances. Bacterial communities of eggs varied more greatly between tanks than between samples deriving from the same tank. At Day 5, there was a consistent reduction in 16S rRNA gene sequence richness across the tanks. Even though the eggs from the different tanks were incubated in a common holding tank, the bacterial communities of the eggs from the different tanks had diverged to become increasingly dissimilar. This suggests that the disinfection and incubation exerted differential effects of the microbiota of the eggs from each tank and that the influence of the tank water on the composition of the egg microbiota was lower than expected. This first comprehensive description of the ballan wrasse egg bacterial community is an initial step to understand the role and function of the microbiota on the phenotype of this fish. In future, mass DNA sequencing methods may be applied in hatcheries to screen for pathogens and as a tool to assess the health status of eggs
Chromatin structure of erythroid-specific genes of immature and mature chicken erythrocytes
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