534 research outputs found
Relationship between natriuretic peptide concentration in plasma and posture during blood sampling
Improved immunoradiometric assay for plasma renin
BACKGROUND: Our renin IRMA overestimated renin in plasmas with high
prorenin-to-renin ratios. We suspected that the overestimation of renin
was caused less by cross-reactivity of the renin-specific antibody with
prorenin than by a conformational change of prorenin into an enzymatically
active form during the assay. METHODS: Because the inactive form of
prorenin converts slowly into an active form at low temperature, we raised
the assay temperature from 22 degrees C to 37 degrees C, simultaneously
shortening the incubation time from 24 to 6 h. The former IRMA was
performed in <1 working day with these modifications. RESULTS: The
comeasurement of prorenin as renin was eliminated. Reagents were stable at
37 degrees C, and the new and old IRMAs were comparable in terms of
precision and accuracy. The functional lower limit of the assay (4 mU/L)
was below the lower reference limit (9 mU/L). The modified IRMA agreed
closely with the activities measured with an enzyme-kinetic assay. Results
were not influenced by the plasma concentration of angiotensinogen. At
normal angiotensinogen concentrations, the IRMA closely correlated with
the classical enzyme-kinetic assay of plasma renin activity. CONCLUSION:
The modified IRMA, performed at 37 degrees C, avoids interference by
prorenin while retaining the desirable analytical characteristics of the
older IRMA and requiring less time
Structure and Regulation of Prorenin
The treatment and prevention of cardiovascular disease is one ofthe triumphs of modern
medicine but we have a long way to go before this success is completed. Heart attack
and stroke are still common and, in the western world, cardiovascular disease remains
the main cause of morbidity and mortality.
A major player in cardiovascular homeostasis is the renin.angiotensin system (RAS),
and the growing knowledge of this system has led to the development of agents that
specifically interact with components that are part of the RAS. 'Anti-RAS' drugs are
now widely used in the management of hypertension, heart failure and diabetic
nephropathy. However, as is true for cardiovascular medicine in general, many problems
remain to be solved. Our understanding of how the RAS works and how to modify its
actions is still far from complete.
One century ago Tigerstedt and Bergmann coined the name 'renin' for a hypertensive
factor in rabbit kidney. I They showed that this factor was present in renal cortex and that
it was secreted into renal venous blood. It was retained by dialysis membranes and sensitive
to heat, which suggested its protein. nature. After these initial observations renin sank
into oblivion for a few decades until interest flared up after the experiments by Goldblatt
et al., who showed that clamping a renal artery in a dog caused hypertension. They
believed a humoral factor to be the hypertensive principle, which was shown to be renin
by Pickering et al. From then on unraveling of the structure of what nowadays is known
as the RAS made steady progress, culminating in the cloning of the genes of its
constituents
Relationship between natriuretic peptide concentration in plasma and posture during blood sampling
Angiotensin II type 2 receptors and cardiac hypertrophy in women with hypertrophic cardiomyopathy
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
Angiotensin II type 2 receptors and cardiac hypertrophy in women with hypertrophic cardiomyopathy
Mateship and Money-Making: Shearing in Twentieth Century Australia
After the turmoil of the 1890s shearing contractors eliminated some of the frustration from shearers recruitment. At the same time closer settlement concentrated more sheep in small flocks in farming regions, replacing the huge leasehold pastoral empires which were at the cutting edge of wool expansion in the nineteenth century. Meanwhile the AWU succeeded in getting an award for the pastoral industry under the new arbitration legislation in 1907. Cultural and administrative influences, therefore, eased some of the bitter enmity which had made the annual shearing so unstable. Not all was plain sailing. A pattern of militancy re-emerged during World War I. Shearing shed unrest persisted throughout the interwar period and during World War II. In the 1930s a rival union with communist connections, the PWIU, was a major disruptive influence. Militancy was a factor in a major shearing strike in 1956, when the boom conditions of the early-1950s were beginning to fade. The economic system did not have satisfactory mechanisms to cope. Unionised shearers continued to be locked in a psyche of confrontation as wool profits eroded further in the 1970s. This ultimately led to the wide comb dispute, which occurred as wider pressures changed an economic order which had not been seriously challenged since Federation, and which the AWU had been instrumental in shaping. Shearing was always identified with bushworker ‘mateship’, but its larrikinism and irreverence to authority also fostered individualism, and an aggressive ‘moneymaking’ competitive culture. Early in the century, when old blade shearers resented the aggressive pursuit of tallies by fast men engaged by shearing contractors, tensions boiled over. While militants in the 1930s steered money-makers into collectivist versions of mateship, in the farming regions the culture of self-improvement drew others towards the shearing competitions taking root around agricultural show days. Others formed their own contracting firms and had no interest in confrontation with graziers. Late in the century New Zealanders arrived with combs an inch wider than those that had been standard for 70 years. It was the catalyst for the assertion of meritocracy over democracy, which had ruled since Federation
Quality of herbage at different latitudes.
In a cooperative experiment, yield and herbage quality of timothy was measured during the uninterrupted growth of the 1st cut at 6 lat. (51-69 deg N). Rate of production was greatest at Tromso (69 deg N), apparently because of the long day and rapid reproductive development. Digestibility of OM declined faster at higher lat. because stem development proceeded faster and less leaf DM was produced. At the same morphological stage, digestibility of the whole crop was better at higher lat. because of the better digestibility of the cell walls from the stems. It was concluded that rate of lignification could not keep pace with the rapid rate of stem development. (Abstract retrieved from CAB Abstracts by CABI’s permission
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