Nicholas Manitius to Brother James Meredith (8 October 1962)

https://egrove.olemiss.edu/mercorr_pro/2051/thumbnail.jp

Projection series for retarded functional differential equations with applications to optimal control problems

AbstractIn this paper projection methods based on expansions of solutions of retarded function differential equations in terms of generalized eigenfunctions are considered. It is first shown that the projection series developed earlier by Hale and Shimanov and those considered by Bellman and Cooke are actually the same. Using extensions of the residue-type arguments of Bellman and Cooke, convergence results are then established for a class of perturbed systems. These results are applied to obtain approximations to optimal controls for certain infinite dimensional variational problems. Numerical results are presented for several examples

The relationship between blood pressure changes and the efficacy of treatment in patients with primary glomerulonephritis with special regard to kidney size

Introduction. Blood pressure plays a modulating role in the progression of glomerulonephritis. Kidney size could also constitute a factor influencing the efficacy of treatment. The study sought to determine renal length and the influence of blood pressure changes and renal length on the efficacy of treatment. Material and methods. This study included 53 adult patients (25 female and 28 male), aged 17 to 63. At the beginning of the observation period, the following tests were performed: percutaneous renal biopsy, anthropometric measurements, renal length in abdominal ultrasound scan. At the beginning of the observation period and after 24 months the following tests were performed: SBP, DBP, MAP, PP, serum creatinine level, GFR MDRD, DPL. Absolute renal length (D) was related to anthropometric parameters and values of relative renal length D/H, D/BSA, D/BMI were calculated. Results. D value ranged from 93.5 mm to 135.5 mm. Mean values of parameters were: D/H 0.67 ± 0.07 mm/cm, D/BSA 61.8 ± 8.7 mm/m2, D/BMI 4.67 ± 0.79 mm/kg/m2. No correlations were found of DPL changes and GFR MDRD changes with arterial pressure. A correlation was found between DPL changes and D. In patients whose DPL values decreased by at least 50%, mean values of D, D/H and D/BSA were higher. No correlations were found of GFR MDRD changes with D, D/H, D/BSA or D/BMI. Conclusions. No influence of arterial blood pressure on the efficacy of treatment was discovered. Renal length is not a prognostic factor for changes in glomerular filtration rate; however, it can be a prognostic factor for proteinuria changes

An intradialytic blood pressure assessment extended by two weeks predicts cardiovascular events with an accuracy comparable to that of home blood pressure measurements among hemodialysis patients

Introduction. Pressure measurements obtained before and after hemodialysis (HD) are marked by their high variability and poor reliability, which undermine their ability to estimate cardiovascular events (CVs). Objective. This study sought to determine whether more measurements performed over a longer period of time enable a more accurate evaluation of the CVs associated with arterial hypertension. Material and methods. This study included 40 patients (23 men and 17 women) aged between 27 and 82 years with a mean age of 58.8 } 13.6 years who underwent chronic HD for 4 to 338 months. On days without HD, blood pressure home measurements (HMs) were recorded in the morning, afternoon and evening, and the results were obtained each day for 8 days. Furthermore, pressure measurements were recorded five times during 7 subsequent planned HD procedures: before HD, after HD and three times during HD. After 12 months, the number of CVs was determined with respect to the pressure measurement method. Results. The correlation coefficients between the HMs and HD with regard to systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were 0.85, 0.80, and 0.84, respectively (P < 0.001). The receiver operating curve (ROC) values for SBP were 137.8 mmHg for HM and 140.4 mmHg for HD. The sensitivity and specificity of the HMs for SBP were 0.667 and 0.727, respectively. CVs occurred in 66.7% of the patients with SBPs ≥ 137.8 mmHg. The sensitivity and specificity of the HD measurements of SBP were 0.611 and 0.818, respectively. CVs occurred in 73.3% of patients with SBPs ≥ 140.4 mmHg. Conclusions. Increasing the number of pressure measurements over a longer period of time in patients with HD likely improves the reliability of CV risk estimates.

The role of aldosterone in kidney diseases and hypertension. Is it worth using mineralocorticoid receptor antagonists in clinical practice?

Aldosterone is a mineralocorticoid hormone which plays a pivotal role in water and electrolytes balance. Moreover,aldosterone exerts a deleterious influence on the cardiovascular system and kidneys. In this review, we wanted toshow mechanisms of aldosterone related organ damage, the role of aldosterone in kidney diseases, hypertension andtherapeutic benefits related with aldosterone receptors blockade

Circadian blood pressure profile in patients with chronic kidney disease stage 1–3

Wstęp. Populacja chorych z CKD charakteryzuje się wysoką chorobowością i śmiertelnością sercowo-naczyniową. Ta grupa pacjentów charakteryzuje się zaburzonym dobowym profilem ciśnienia tętniczego, a cecha ta może zwiększać ryzyko sercowo-naczyniowe. Celem pracy była analiza dobowego rytmu ciśnienia tętniczego u pacjentów we wczesnych stadiach CKD. Materiał i metody. Badaniem objęto 90 chorych w 1-3 stadium CKD w wieku 34-79 lat oraz 30 osób w wieku 38-79 lat stanowiących grupę kontrolną. U wszystkich badanych przeprowadzono ambulatoryjne monitorowanie ciśnienia tętniczego (ABPM). Jeśli względne obniżenie SBP i DBP w nocy wynosiło co najmniej 10% pacjenta kwalifikowano jako „dipper”, natomiast jeśli spadek SBP i DBP był mniejszy niż 10% pacjenta kwalifikowano jako „non-dipper”. Wyniki. Nadciśnienie tętnicze występowało u 78.9% pacjentów z CKD w stadium 1-3. Profil „non-dipper” stwierdzono u 59(66%) spośród badanych chorych z CKD, w tym w stadium 1 CKD u 16(53%), w stadium 2 CKD u 23(70%) oraz u 20(74%) w stadium 3 CKD. W grupie kontrolnej profil non-dipper stwierdzono u 9 (30%) pacjentów. W badanej całej populacji (n=120) stwierdzono znamienną statystycznie dodatnią korelację między % spadkiem SBP i eGFR (r=0.25;pBackground The population of patients with chronic kidney disease (CKD) is prone to high cardiovascular morbidity and mortality. Aberrant circadian pattern of blood pressure is associated with increase cardiovascular risk. The study investigated circadian blood pressure profile in patients with early stages of CKD. Material and methods The study included 90 patients with CKD stage 1–3, aged 34–79 years and 30 healthy volunteers as control group. All patients underwent ambulatory blood pressure monitoring (ABPM). Patient was classified as “dipper” if relative decreases in SBP and DBP at night was at least 10%. If the drop the SBP or DBP was less than 10% patient was classified as “non-dipper”. Results Hypertension was present in 78.9% of patients with CKD stage 1–3. “Non-dipper” profile was found in 59 (66%) of the surveyed patients with CKD, namely in 16 (53%) in CKD stage 1, 23 (70%) in CKD stage 2, and 20 (74%) in CKD stage 3. “Non-dipper” profile was observed in 9 (30%) of control patients. In the whole study population (n = 120) significant positive correlation was found between % drop in SBP and eGFR (r = 0.25; p < 0.01). There was no significant correlation between % drop in SBP and eGFR (r = 0.12; p = 0.26) in 90 CKD patients. There was statistically significant negative correlation between % drop in SBP and age (r = –0.25; p < 0.05) and BMI (r = –0.24; p < 0.05). Conclusions “Non-dipper” profile is a common finding among patients with early stages of CKD and may be associated with a higher cardiovascular risk. ABPM should be a standard procedure in patients with CKD, even in early stages of the disease

Dynamical observer for a flexible beam via finite element approximations

The purpose of this view-graph presentation is a computational investigation of the closed-loop output feedback control of a Euler-Bernoulli beam based on finite element approximation. The observer is part of the classical observer plus state feedback control, but it is finite-dimensional. In the theoretical work on the subject it is assumed (and sometimes proved) that increasing the number of finite elements will improve accuracy of the control. In applications, this may be difficult to achieve because of numerical problems. The main difficulty in computing the observer and simulating its work is the presence of high frequency eigenvalues in the finite-element model and poor numerical conditioning of some of the system matrices (e.g. poor observability properties) when the dimension of the approximating system increases. This work dealt with some of these difficulties

Controversy over renin–angiotensin–aldosterone system (RAAS) inhibitors treatment in nephrology and cardiovascular diseases

Drugs that act by inhibiting the renin–angiotensin–aldosterone system (RAAS), such as angiotensin-converting enzymeinhibitors (ACE-Is) and angiotensin II receptor type 1 (AT1) blockers (ARBs), have been recognized as a basiccanon of nephroprotection for years. They are commonly used in monotherapy for glomerulonephritis with proteinuria.At present, they are rarely used in combination therapy in a form of dual blockade of RAAS due to concernabout possible side effects. On the other hand, both ACE-Is and ARBs are also wrongly referred to as nephrotoxicdrugs. The significance of therapy with these drugs is seen in evoking acute kidney injury (AKI) or acceleration ofCKD. The aim of this article was to clarify the opinion on the relationship between ACE-Is or ARBs treatment andAKI occurrence, and to attempt to reassess the role of dual RAAS blockade in the treatment of kidney diseases. Theprinciples of heart failure (HF) therapy with ACE-Is or ARBs and current data on the importance of RAAS dualblockade in hypertension are also discussed

Anemia in Chronic Kidney Disease (Ckd). Do we know how to Treat it Properly?

Renal anemia is one of the major complications observed in patients with chronic kidney disease (CKD). It is caused mainly by a relative erythropoietin deficiency due to progressive damage of renal parenchyma. The primary goal of anemia treatment using available today ESAs is not only to improve the quality of life of patients but, above all to reduce cardiovascular mortality. The target hemoglobin concentration during application of ESA in CKD patients treated conservatively and renal replacement therapy patients was and still is being discussed among nephrologists. Based on the clinical trials performed so far, it seems that in patients with renal anemia we should individualise treatment with ESA, seeking partial rather than complete correction of anemia.Niedokrwistość nerkopochodna jest jednym z istotnych powikłań obserwowanych u pacjentów z przewlekłą chorobą nerek (PCHN). Jest ona spowodowana głównie względnym niedoborem erytropoetyny wskutek postępującego uszkodzenia miąższu nerek. Podstawowym celem leczenia niedokrwistości przy pomocy dostępnych współcześnie czynników stymulujących erytropoezę (ESA) jest nie tylko poprawa jakości życia chorych, ale przede wszystkim zmniejszenie śmiertelności sercowo-naczyniowej. Docelowe stężenie hemoglobiny w czasie stosowania ESA u pacjentów z PChN leczonych zachowawczo, jak i dializowanych, było i nadal jest przedmiotem dyskusji w środowisku nefrologicznym. W oparciu o przeprowadzone do tej pory badania kliniczne wydaje się, iż w przypadku chorych z niedokrwistością nerkopochodną należy prowadzić indywidualizację leczenia z zastosowaniem ESA, dążąc raczej do częściowej niż całkowitej korekcji niedokrwistości