Sodium-Glucose Cotransporter 2 Inhibitors in Frail Patients with Heart Failure: Clinical Experience of a Heart Failure Unit

OBJECTIVE

The objective of this study was to determine the difference in tolerance for sodium glucose cotransporter 2 inhibitors between patients with heart failure classified as frail according to the FRAIL questionnaire, compared to those with heart failure without frailty.

METHODS

A prospective cohort study was performed between 2021 and 2022 that included patients with heart failure at a heart failure unit in Bogotá who were being treated with a sodium glucose cotransporter 2 inhibitor. Clinical and laboratory data were collected during an initial visit and 12-48 weeks after that. The FRAIL questionnaire was applied to all participants through a phone call or during the follow-up visit. The primary outcome was the adverse effect rate and as a secondary outcome we compared the estimated glomerular filtration rate change between frail and non-frail patients.

RESULTS

One hundred and twelve patients were included in the final analysis. Frail patients had a more than twice increased risk of having adverse effects (95% confidence interval 1.5-3.9). Age was also a risk factor for the appearance of these.  The estimated glomerular filtration rate decrease was inversely correlated with the age, left ventricular ejection fraction, and renal function before the use of sodium glucose cotransporter 2 inhibitors.

CONCLUSIONS

When prescribing in heart failure, it is important to remember that frail patients are more likely to have adverse effects with the use of sodium glucose cotransporter 2 inhibitors, of which the most common are those related to osmotic diuresis. Nonetheless, these do not appear to increase the risk of discontinuation or abandonment of therapy in this population.

Growth of Nitrogen Incorporated Ultrananocrystalline Diamond Coating on Graphite by Hot Filament Chemical Vapor Deposition

This article shows the results of experiments to grow Nitrogen incorporated ultrananocrystalline diamond (N-UNCD) films on commercial natural graphite (NG)/Cu anodes by hot chemical vapor deposition (HFCVD) using a gas mixture of Ar/CH₄/N₂/H₂. The experiments focused on studying the effect of the pressure in the HFCVD chamber, filament-substrate distance, and temperature of the substrate. It was found that a substrate distance of 3.0 cm and a substrate temperature of 575 C were optimal to grow N-UNCD film on the graphite surface as determined by Raman spectroscopy, SEM, and TEM imaging. XPS analysis shows N incorporation through the film. Subsequently, the substrate surface temperature was increased using a heater, while keeping the substrate-filament distance constant at 3.0 cm. In this case, Raman spectra and SEM images of the substrate surface showed a major composition of graphite in the film as the substrate-surface temperature increased. Finally, the process pressure was increased to 10 Torr where it was seen that the growth of N-UNCD film occurred at 2.0 cm at a substrate temperature of 675 C. These results suggest that as the process pressure increases a smaller substrate-filament distance and consequently a higher substrate surface temperature can still enable the N-UNCD film growth by HFCVD. This effect is explained by a mean free path analysis of the main precursors H₂ and CH₃ molecules traveling from the filament to the surface of the substrate The potential impact of the process developed to grow electrically conductive N-UNCD films using the relatively low-cost HFCVD process is that this process can be used to grow N-UNCD films on commercial NG/Cu anodes for Li-ion batteries (LIBs), to enable longer stable capacity energy vs. charge/discharge cycles.

Computer tool with intelligent behavior for the optimal preliminary design in non-braced structural steel frame

The optimization of civil structures is a technique whose purpose is to efficiently use the materials that make up the structural systems based on previously established restrictions and objectives. The use and development of these techniques has been closely linked to technological advance since, through the use of computer equipment, complex mathematical models can be solved with low cost and time. This article presents OPS Design v2.0, a computer tool that allows obtaining a preliminary optimal distribution of metallic structural profiles in a Non-Braced Frame System (OMF: Ordinary Moment Frame). The optimization model implemented in OPS Design v2.0 seeks to minimize the number of different profiles and the structure's own weight in order to reduce the construction complexity and the weight per linear meter (costs in quantities of material). To evaluate its effectiveness, a case study was developed where it was concluded that the designs produced by the application are more efficient than those obtained by commercial tools, thus reducing the computational expense and time used by designers in iterative processes that are carried out in the initial phases project.

Diverse and Complementary Effects of Ghrelin and Obestatin

Ghrelin and obestatin are two “sibling proteins” encoded by the same preproghrelin gene but possess an array of diverse and complex functions. While there are ample literature documenting ghrelin’s functions, the roles of obestatin are less clear and controversial. Ghrelin and obestatin have been perceived to be antagonistic initially; however, recent studies challenge this dogma. While they have opposing effects in some systems, they function synergistically in other systems, with many functions remaining debatable. In this review, we discuss their functional relationship under three “C” categories, namely complex, complementary, and contradictory. Their functions in food intake, weight regulation, hydration, gastrointestinal motility, inflammation, and insulin secretion are complex. Their functions in pancreatic beta cells, cardiovascular, muscle, neuroprotection, cancer, and digestive system are complementary. Their functions in white adipose tissue, thermogenesis, and sleep regulation are contradictory. Overall, this review accumulates the multifaceted functions of ghrelin and obestatin under both physiological and pathological conditions, with the intent of contributing to a better understanding of these two important gut hormones.

Lambl's Excrescences: An Enigma of Modern Diagnostic Cardiology

Lambl's excrescences were first described in 1856 by a Bohemian physician, Vilém Dušan Lambl, and since then have gained widespread attention and controversy within the medical literature. Despite numerous case reports and observational studies, consensus on the significance and management of Lambl’s excrescences remains sparse. We describe the case of a 48-year-old male who presented with recurrent embolic strokes. No underlying paroxysmal arrhythmia or inter-atrial shunt was identified, and the only pathological finding was a 1-mm aortic valve strand. We managed this patient successfully using a novel oral anticoagulant.

A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other important biological functions. The islets primarily consist of five types of hormone-secreting cells: α cells secrete glucagon, β cells secrete insulin, δ cells secrete somatostatin, ε cells secrete ghrelin, and PP cells secrete pancreatic polypeptide. Sixty to 80% of the cells in the islets are β cells, which are the most important cell population to study insulin secretion. Pancreatic islets are a crucial model system to study ex vivo insulin secretion. Acquiring high quality islets is of great importance for diabetes research. Most islet isolation procedures require technically difficult to access site of collagenase injection, harsh and complex digestion procedures, and multiple density gradient purification steps. This paper features a simple high yield mouse islet isolation method with detailed descriptions and realistic demonstrations, showing the following specific steps: 1) injection of collagenase P at the ampulla of Vater, a small area joining the pancreatic duct and the common bile duct, 2) enzymatic digestion and mechanical separation of the exocrine pancreas, and 3) a single gradient purification step. The advantages of this method are the injection of digestive enzyme using the more accessible ampulla of Vater, more complete digestion using combination of enzymatic and mechanical approaches, and a simpler single gradient purification step. This protocol produces approximately 250-350 islets per mouse; and islets are suitable for various ex vivo studies. Possible caveats of this procedure are potentially damaged islets due to enzymatic digestion and/or prolonged gradient incubation, all of which can be largely avoided by careful ad justification of incubation time.

Phosphorylation of Forkhead Protein FoxO1 at S253 Regulates Glucose Homeostasis in Mice

The transcription factor forkhead box O1 (FoxO1) is a key mediator in the insulin signaling pathway and controls multiple physiological functions, including hepatic glucose production (HGP) and pancreatic β-cell function. We previously demonstrated that S256 in human FOXO1 (FOXO1-S256), equivalent to S253 in mouse FoxO1 (FoxO1-S253), is a key phosphorylation site mediating the effect of insulin as a target of protein kinase B on suppression of FOXO1 activity and expression of target genes responsible for gluconeogenesis. Here, we investigated the role of FoxO1-S253 phosphorylation in control of glucose homeostasis in vivo by generating global FoxO1-S253A/A knockin mice, in which FoxO1-S253 alleles were replaced with alanine (A substitution) blocking FoxO1-S253 phosphorylation. FoxO1-S253A/A mice displayed mild increases in feeding blood glucose and insulin levels but decreases in fasting blood glucose and glucagon concentrations, as well as a reduction in the ratio of pancreatic α-cells/β-cells per islet. FoxO1-S253A/A mice exhibited a slight increase in energy expenditure but barely altered food intake and glucose uptake among tissues. Further analyses revealed that FoxO1-S253A/A enhances FoxO1 nuclear localization and promotes the effect of glucagon on HGP. We conclude that dephosphorylation of S253 in FoxO1 may reflect a molecular basis of pancreatic plasticity during the development of insulin resistance.

Antibiotic resistance profile in eye infections in a reference centre in Floridablanca, Colombia

BACKGROUND AND OBJECTIVE

In view of the increasing bacterial resistance to antibiotics, it is necessary to determine it locally in order to serve as a guide in clinical management. The purpose of this study was to characterise the pattern of antibiotic sensitivity in cases of eye infections in a third level ophthalmological institution in Floridablanca (Colombia).

MATERIALS AND METHODS

An observational cross-sectional study in which an analysis was made of the culture and antibiogram reports of specimens taken from cases of conjunctivitis, infectious keratitis, and endophthalmitis between January 2013 and June 2016.

RESULTS

A total of 833 specimens were positive for bacteria. Considering both gram-positive and gram-negative microorganisms gentamicin, tobramycin, and ciprofloxacin showed high resistance rates (64.4%, 40.3%, and 29.1%, respectively). Moxifloxacin, vancomycin, imipenem, and gatifloxacin showed low percentages of resistance: 2.6%, 2.1%, 0.6%, and 0.4%, respectively. When comparing the results with previous studies in our institution, there was a decrease in sensitivity to the fourth-generation quinolones and imipenem, especially within the gram-negative ones.

CONCLUSION

Fourth generation quinolones, imipenem and vancomycin continue to have a low in vitro resistance to bacteria that cause eye infections. However, there was a tendency to an increase in the resistance of gram-negative bacteria. Measures should be taken to try to control this phenomenon, and consider possible antimicrobial therapy alternatives to infections caused by these microorganisms.

Mycotic keratitis caused by Scedosporium apiospermum in an immunocompetent patient

CLINICAL CASE

A 51 year-old immunocompetent male was referred due to presenting with a large corneal ulcer with hypopyon in the right eye. Topical amphotericin B, fluconazole and moxifloxacin, as well as oral itraconazole were initially indicated. Following the report of mycotic structures on staining, topical natamycin was started. The result of the culture was reported two weeks later as, Scedosporium apiospermum (S. apiospermum), and topical voriconazole was then added. The response to treatment was very slow, and took five weeks after receiving triple therapy (natamycin, voriconazole and fluconazole) and one dose of intrastromal voriconazole, for the hypopyon to disappear. The final outcome was successful, achieving healing of the ulcer. The patient is waiting for a corneal transplant.

DISCUSSION

A microbiological study is essential in patients in whom fungal keratitis is suspected. The treatment of choice against S. apiospermum is with voriconazole, but the combination of various antifungal agents may be required.

The relationship between Type D personality and insomnia

OBJECTIVES

Type D personality is characterized by the combination of social inhibition and negative affectivity. This study examined the relationship between Type D personality and insomnia symptoms amongst a sample of the general-population.

METHODS

Adults from the general-population (n = 392) completed online measures of Type D personality (DS14) and insomnia severity.

RESULTS

Individuals with the Type D personality trait reported significantly greater symptoms of insomnia relative to Non-Type Ds. Moreover, insomnia-symptoms were independently related to negative affectivity (NA) and social inhibition (SI) and the Type D interaction (i.e. synergistic product of SI and NA). Linear regression analysis determined that NA but not SI significantly predicted insomnia symptoms after controlling for age and sex. However, after accounting for the Type D interaction, negative affectivity remained the only significant predictor of insomnia-symptoms.

CONCLUSIONS

The Type D personality type appears to be related to insomnia-symptoms, both as a categorical and dimensional construct. These outcomes support prior research evidencing that whilst Type D personality is related to poor sleep in adolescents, NA appears to be the main contributor.

Reciprocal ST-Segment Changes in Myocardial Infarction: Ischemia at Distance Versus Mirror Reflection of ST-Elevation

BACKGROUND

Reciprocal ST-depression in the electrocardiograms (ECGs) of patients with ST-elevation myocardial infarction (STEMI) results from either true ischemia at a distance via collateral circulation diverting blood to the infarcted region or an electrical phenomenon that results from a mirror reflection of ST-elevation. We aimed to identify the role of reciprocal ECG changes in predicting collateral circulation to the infarcted area determined angiographically.

METHODS

In a retrospective study, ECG and angiography of 53 STEMI patients admitted to SUNY Upstate Medical University in 2014 were reviewed independently by experts blinded to the results of ECG and coronary angiography.

RESULTS

Reciprocal changes (RC) in ECG were present in 41 patients (77%) and on angiography, 14 patients (26%) exhibited collateral vessels to the ischemic areas. No correlation was found between the presence of RC and collateral circulation (P = 0.384), or between the depth of reciprocal ST-depression and the degree of the collateral circulation (P = 0.195). However, 84% of patients without collaterals exhibited resolution of RC after successful percutaneous coronary intervention (PCI) (P = 0.036), suggesting that the ST depressions that resolved after reperfusion were directly caused by the culprit vessel. Patients without RC presented late after symptom onset (9.25 versus 3.83 hours, P = 0.004), also suggesting time related resolution.

CONCLUSIONS

RC had no relation to or predictive value for collaterals on angiography. Among late presenting patients, RC were less frequent. Thus, reciprocal ST-depression may represent subendocardial ischemia from the primary coronary event or simply an electrical phenomenon, rather than ischemia at distance from impaired collateral circulation.

Renal Denervation in Heart Failure: A New Therapeutic Paradigm

Heart failure constitutes a significant source of morbidity and mortality in the United States, and its incidence and prevalence continue to grow, increasing its burden on the health care system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This complex interaction is characterized by a pathophysiological disequilibrium between the heart and the kidney, in which cardiac malfunction promotes renal impairment, which in turn feeds back, resulting in further deterioration of cardiovascular function. Multiple neurohumoral and hemodynamic mechanisms are involved in this cardiorenal dyshomeostasis, including resistance to compensatory cardiac natriuretic peptides, leading to sodium retention, volume overload, and organ remodeling. Previous studies in animal models of heart failure have demonstrated that renal denervation promotes a robust natriuresis and diuresis as well as increased response of endogenous and exogenous natriuretic agents. With the recent development of minimally invasive renal denervation in humans, it is possible to suggest that this technique may become effective and important in the management of renal sodium and water metabolism in heart failure.

A single immunization with optimized DNA vaccines protects against lethal Ebola virus challenge in mice (VAC8P.1057)

Ebola is a hemorrhagic fever virus that is responsible for the severe, ongoing outbreak in West Africa that has infected >20000 people, exhibiting >37% mortality. Infection control has been complicated by a lack of approved vaccines and therapies and recent figures suggest that the outbreak is more severe than previously thought. We generated 3 DNA vaccines expressing Zaire ebolavirus (EBOV) glycoprotein (GP): 2 vaccines designed on consensus alignments of EBOV GPs (1976-2014) and a 3rd matched construct to a 2014 Guinea strain. BALB/c mice received 40ug of each vaccine, delivered by IM injection followed by electroporation. Strong T cell responses were detected for all 3 vaccines, including GP-specific CD4+ and CD8+ T cells. To broaden efficacy against emerging EBOV strains, we also co-administered DNA vaccines in 2 or 3 construct formulations. Groups of 10 BALB/c mice were challenged with a lethal dose of a heterologous mouse-adapted Mayinga 1976 EBOV strain. The two consensus DNA vaccines, and combinations of 2 and 3 vaccines were 100% protective in mice. The matched vaccine afforded 90% protection. Total GP-specific IgG antibody levels were high in all surviving animals and low in unprotected animals suggesting that titers may indicate therapeutic efficacy. All three DNA vaccines are immunogenic and no antigen interference was observed. These experiments in mice support further studies in non-human primates towards continued development of this potential vaccine platform.

Neonatal presentation of incontinentia pigmenti with a family history extending over four generations--a case report

We report a case of Incontinentia pigmenti (IP). A day 2 female presented to the special care nursery with seizures. EEG showed multifocal epileptiform discharges and cranial MRI revealed extensive cerebral infarction. A rash appeared shortly after birth. Eye examination revealed changes of IP. There is a strong family history of IP. Genetic testing excluded the most common mutation. Follow-up reveals significant development delay.

Effects of Chronic Nitric Oxide Inhibition on the Renal Excretory Response to Leptin

OBJECTIVE

Previous investigations have demonstrated that leptin promotes natriuresis with a renal tubular effect. However, the mechanisms involved in this response are unclear. The present study was designed to examine the hypothesis that the natriuretic response to leptin in normotensive Sprague-Dawley rats is regulated by nitric oxide (NO).

RESEARCH METHODS AND PROCEDURES

The hemodynamic and renal excretory effects of intravenous bolus administration of pharmacological doses of synthetic murine leptin were examined in groups of control Sprague-Dawley rats (n = 8), Sprague-Dawley rats treated for 4 days with the NO synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME) (n = 8), and Sprague-Dawley rats treated for 4 days with L-NAME followed by acute treatment with sodium nitroprusside (n = 8).

RESULTS

In the control group (n = 8), an intravenous bolus of leptin, 400 microg/kg body weight, increased urinary sodium excretion 4- to 6-fold. In the Sprague-Dawley rats chronically administered l-NAME (n = 8), an intravenous bolus of 400 microg/kg of leptin did not increase sodium excretion. Acute sodium nitroprusside infusion to Sprague-Dawley rats chronically treated with L-NAME (n = 8) was associated with partial restoration of the sodium excretory response to leptin administration.

DISCUSSION

Collectively, these results are interpreted to suggest that the natriuretic and diuretic responses to leptin observed in the Sprague-Dawley rat require a functional NO system.

Angina pectoris in a patient with protein C deficiency and deep vein thrombosis: thrombus versus myxoma?

A 55-year-old Caucasian man with history of hypertension, diabetes mellitus, protein C deficiency, and deep vein thrombosis presented with typical angina. Both computed tomography and transesophageal echocardiography identified a mobile mass in left atrium but could not differentiate between thrombus and myxoma. A cardiac catheterization with coronary angiography demonstrated tumor neovascularization, suggestive of myxoma. Pathology examination after mass resection confirmed the diagnosis. Patients with myxoma could present with obstructive, embolic, or constitutional symptoms. However, typical angina has never been reported as the primary manifestation. Although being helpful, various noninvasive imaging modalities, including magnetic resonance image, often have limitations to help making a definitive diagnosis, before surgery decision, especially under hypercoagulable condition. In contrast, cardiac catheterization can help not only in differentiation diagnosis but also in detecting possible intracoronary embolization from myxoma. In patients with myxoma complicated with hypercoagulable disorders, anticoagulation will play essential role in long-term care.

Heart failure mice exhibit decreased gastric emptying and intestinal absorption

Our recent study showed that intravenously administered B-type natriuretic peptide (BNP) decreases gastric emptying and intestinal absorption in mice. We aimed to test whether acute myocardial injury and heart failure have similar effects. Wild-type (WT) and natriuretic peptide receptor type A (NPR-A) knockout (KO) mice underwent cryoinfarction (myocardial infarction [MI]) of the left ventricle (LV) versus sham. LV dysfunction was confirmed by echocardiography. Percent gastric emptying and intestinal absorption were measured and analyzed one and two weeks after infarction, by gavage feeding the mice with fluorescein-isothiocyanate-dextran. Ejection fraction was 48 ± 3% versus 64 ± 2% ( P < 0.05) and fractional shortening was 24 ± 2% versus 35 ± 2% ( P < 0.01), MI versus sham, respectively. BNP levels (pg/mL) were 4292 ± 276 one week after MI versus 105 ± 11 in sham ( n = 5, P < 0.05) and 1964 ± 755 two weeks after MI ( n = 5, P < 0.05). Gastric emptying was significantly decreased, 68 ± 6% in MI versus 89 ± 3% in sham ( n = 5, P < 0.05) one week after MI and 82 ± 0.5% versus 98 ± 0.4%, MI versus sham ( n = 5, P < 0.05), two weeks post-MI. Absorption, measured in relative plasma fluorescence units in WT mice, was 350 ± 79 in MI versus 632 ± 121 in sham ( n = 6, P < 0.05). KO mice did not show a significant difference in emptying or absorption compared with sham. These findings suggest that MI and LV dysfunction decrease gastric emptying and absorption in mice through a mechanism that involves NPR-A.

Obesity hypertension: the regulatory role of leptin

Leptin is a 16-kDa-peptide hormone that is primarily synthesized and secreted by adipose tissue. One of the major actions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake and elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect mechanisms, may play an important role in cardiovascular and renal regulation. While the relevance of endogenous leptin needs further clarification, it appears to function as a pressure and volume-regulating factor under conditions of health. However, in abnormal situations characterized by chronic hyperleptinemia such as obesity, it may function pathophysiologically for the development of hypertension and possibly also for direct renal, vascular, and cardiac damage.

Leptin: linking obesity, the metabolic syndrome, and cardiovascular disease

The incidence and prevalence of obesity and the metabolic syndrome have risen markedly in the past decade, representing a serious cardiovascular health hazard with significant morbidity and mortality. The etiology of the metabolic syndrome and its various pathogenic mechanisms are incompletely defined and under intense investigation. Contemporary research suggests that the adipocyte-derived hormone leptin may be an important factor linking obesity, the metabolic syndrome, and cardiovascular disorders. Although recent evidence indicates that under normal conditions leptin may be an important factor in regulating pressure and volume, during situations of chronic hyperleptinemia and leptin resistance, this hormone may function pathophysiologically for the development of hypertension and cardiac and renal diseases. Future research will determine if reduction of circulating leptin and/or blockade of its peripheral actions can confer cardiovascular and renal protection in hyperleptinemic patients with obesity and the metabolic syndrome.

Obesity-hypertension: emerging concepts in pathophysiology and treatment

The incidence and prevalence of obesity has risen markedly in the last decade, and this epidemic represents a serious health hazard with significant morbidity and mortality. Although hypertension is recognized as one of the most serious consequences of obesity, its pathophysiology remains incompletely understood. Contemporary research suggests that the recently discovered hormone leptin may represent a common link between these 2 pathologic conditions. Leptin is primarily synthesized and secreted by adipocytes. One of the major functions of this hormone is the control of energy balance. By binding to receptors in the hypothalamus, it reduces food intake and promotes elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect actions, may play an important role in cardiovascular and renal functions. Although the relevance of endogenous leptin needs further clarification for the control of renal sodium excretion and vascular tone, it appears to be a potential pressure and volume-regulating factor in normal situations. However, in conditions of chronic hyperleptinemia, such as obesity, leptin may function pathophysiologically for the development of hypertension as well as cardiac and renal disease. Thus, in addition to weight control, reduction of circulating leptin may confer cardiovascular and renal protective effects in patients with obesity-hypertension.

A comparison of the neurotropism of Theiler's virus and poliovirus in CBA mice

Theiler's murine encephalomyelitis virus (TMEV) and poliovirus infect the central nervous system (CNS) and cause neurological damage. The exact route by which TMEV and polioviruses enter the CNS remains, for the most part, unknown, although the neural and/or the hematogenous pathway have both been postulated. To explore these hypotheses, this research focuses on both the site of entry and the pathway used to invade the CNS. Following different inoculation sites of the GDVII strain of Theiler's virus or Lansing Type 2 poliovirus in CBA mice, the incidence of paralysis and/or encephalitis was evaluated on the basis of clinical signs and histopathology. The forms of paralysis displayed corresponded to the site of viral inoculation. Following intramuscular (i.m.), intraperitoneal (i.p.), and footpad routes of injection, bilateral and or contralateral paralyses were observed for both TMEV and poliovirus. In mice injected intratongue and in the hypoglossal nerve, tongue paralysis or paralysis of the forelimb, which progressed to bilateral forelimb paralysis, was observed, additionally the penis of most infected males was protruded. Intracranial (i.c.) injections with type II poliovirus strain resulted in forelimb paralysis. Intravenous (i.v.), injections with TMEV also resulted in forelimb paralysis. Thus Lansing Type II poliovirus and TMEV infections of CBA mice, result in similar incidence of paralysis and histopathological findings.

Leptin blockade attenuates sodium excretion in saline-loaded normotensive rats

Previous investigations in normotensive animals have demonstrated a marked natriuretic and diuretic response following the acute administration of supraphysiologic doses of synthetic leptin. However, the importance of endogenous leptin in the regulation of renal sodium and water balance is not yet defined. This study examined the hemodynamic and renal excretory effects of circulating leptin blockade with a specific polyclonal antibody in groups of normotensive, chronically saline-loaded Sprague-Dawley rats. In the experimental group (n = 10), leptin antibody significantly decreased urinary sodium excretion and urinary flow by approximately 30% compared to the control rats (n = 10). Mean arterial pressure remained unchanged. Collectively, these results are interpreted to suggest that leptin is an important renal sodium-regulating factor under conditions of mild sodium and volume expansion.

Leptin as a common link to obesity and hypertension

Leptin is a recently isolated circulating peptide hormone that is primarily synthesized and secreted by adipocytes. One of the major functions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake, elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect actions, may play an important role in cardiovascular and renal functions. While the relevance of endogenous leptin needs further clarification, it appears to be a potential pressure- and volume-regulating factor, and may function pathophysiologically as a common link to obesity and hypertension.

Leptin as a common link to obesity and hypertension

Leptin is a recently isolated circulating peptide hormone that is primarily synthesized and secreted by adipocytes. One of the major functions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake, elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect actions, may play an important role in cardiovascular and renal functions. While the relevance of endogenous leptin needs further clarification, it appears to be a potential pressure- and volume-regulating factor, and may function pathophysiologically as a common link to obesity and hypertension.

Management of the Metabolic Syndrome

The metabolic syndrome is most commonly defined as the presence of three or more of the following atherogenic risk factors: increased abdominal waist circumference, hypertriglyceridemia, low serum high-density lipoprotein level, raised blood pressure, and a fasting blood sugar level greater than 110 mg/dL. It is associated with increased risk for the development of atherosclerosis and cardiovascular disease. Current management recommendations promote therapeutic lifestyle changes (mainly diet and exercise) for all of the core elements of the syndrome. Pharmacologic therapy is indicated in most patients with atherogenic dyslipidemia and in some with hyperglycemia and raised blood pressure. These therapeutic measures are able to favorably modify the core components of the metabolic syndrome and it is hoped that they will also improve the long-term cardiovascular prognosis in patients with this disorder.

Families’ Perception of the Value of Timed Daily “Family Rounds” in a Trauma ICU

Daily communications between the ICU trauma patients’ families and the trauma team are often limited due to the unpredictable nature of subsequent patient admissions and operative procedures. In order to improve the lines of family-physician communication and educate residents regarding family communication, our level I trauma center instituted daily “Family Rounds” (FR). FR occur at the same time every day, in the patient's ICU room. The purpose of this study was to determine whether families valued the scheduled daily FR, to establish whether FR improved the family-physician relationship, and to delineate strengths and weaknesses of the present structure of our FR. We mailed surveys to family members of trauma patients hospitalized in the trauma ICU for ≥3 days. A total of 55 (22%) families responded. Combining “excellent” and “good” responses, 86.5 per cent of families looked forward to having a specific time of day to meet with the trauma team, and 90 per cent liked having rounds in the ICU room with the patient. However, 36 per cent did not like having only scheduled time for FR. The majority, 75 per cent, believed that all concerns were addressed during FR, and 84.9 per cent rated their overall experience as either excellent or good. Scheduled FR appear to improve communication between trauma surgeons and patients’ families, enhance the family-physician relationship, and strengthen our surgical residency teaching program.

Families' perception of the value of timed daily "family rounds" in a trauma ICU

Daily communications between the ICU trauma patients' families and the trauma team are often limited due to the unpredictable nature of subsequent patient admissions and operative procedures. In order to improve the lines of family-physician communication and educate residents regarding family communication, our level I trauma center instituted daily "Family Rounds" (FR). FR occur at the same time every day, in the patient's ICU room. The purpose of this study was to determine whether families valued the scheduled daily FR, to establish whether FR improved the family-physician relationship, and to delineate strengths and weaknesses of the present structure of our FR. We mailed surveys to family members of trauma patients hospitalized in the trauma ICU for > or = 3 days. A total of 55 (22%) families responded. Combining "excellent" and "good" responses, 86.5 per cent of families looked forward to having a specific time of day to meet with the trauma team, and 90 per cent liked having rounds in the ICU room with the patient. However, 36 per cent did not like having only scheduled time for FR. The majority, 75 per cent, believed that all concerns were addressed during FR, and 84.9 per cent rated their overall experience as either excellent or good. Scheduled FR appear to improve communication between trauma surgeons and patients' families, enhance the family-physician relationship, and strengthen our surgical residency teaching program.

Role of leptin in the regulation of body fluid volume and pressures

Leptin is a circulating polypeptide hormone produced by an adipocyte-specific gene. It regulates energy balance by binding to receptors in the hypothalamus, leading to alterations in food intake, temperature, and energy expenditure. More recent pharmacologic information suggests that this circulating hormone may play an important role in the regulation of body fluid volume and pressures through direct and indirect actions. Although the relevance of the endogenous leptin on cardiovascular and renal function is yet to be clearly determined, it seems to be a potential salt-regulating factor and may function pathophysiologically as a common link to obesity and hypertension.

Natriuretic peptides and salt sensitivity: endocrine cardiorenal integration in heart failure

Mammalian hearts contain a family of peptides with potent natriuretic, diuretic, and vasorelaxant actions. In addition to atrial natruretic peptide (ANP) and brain natriuretic peptide, recent studies in humans and animals have suggested that the N-terminal ANP prohormone fragment 31-67 may represent another adaptive mechanism to achieve body fluid homeostasis. Furthermore, these investigations have also suggested that via different mechanisms of action on target organisms, the C-terminal hormone ANP 99-126 and pro-ANP 31-67 may coordinate and contribute to the regulation of hemodynamic and renal function in pathophysiologic situations, such as heart failure.

Effects of renal denervation on the sodium excretory actions of leptin in hypertensive rats

BACKGROUND

Previous studies from this laboratory have reported a marked attenuation of the renal responses to pharmacologic doses of synthetic murine leptin infused in the spontaneously hypertensive rat (SHR) model compared with normotensive Sprague-Dawley and lean Zucker rat models.

METHODS

In the present study, the hemodynamic and renal excretory effects of an intravenous bolus administration of pharmacologic doses of synthetic murine leptin were examined in groups of anesthetized SHR with unilateral nephrectomy and renal denervation or sham-denervation of the remaining kidney.

RESULTS

In the SHR with acute renal denervation (N = 8), an intravenous bolus of 1600 microg/kg of leptin produced a significant twofold to fourfold elevation in sodium excretion but did not increase natriuresis in the sham-denervated group (N = 6). Chronic renal denervation of one-week duration (N = 8) was associated with qualitatively and quantitatively similar increases of sodium excretion in response to leptin administration. Mean arterial pressure remained unchanged in all groups after the administration of leptin.

CONCLUSIONS

Collectively, these results are interpreted to suggest that the blunted natriuretic and diuretic responses to leptin observed in the SHR with intact renal nerves may be partially explained by the antinatriuretic effect of an enhanced baseline efferent renal sympathetic activity and/or leptin's stimulation of the sympathetic nervous system.

Modulation of renin secretion by atrial natriuretic factor prohormone fragment 31-67

BACKGROUND

Earlier studies have indicated that the atrial natriuretic factor prohormone fragment 31-67 (Pro ANF31-67) has important effects for the promotion of sodium excretion and vasodilation in several animal species. However, the mechanisms for the natriuretic actions of Pro ANF31-67 are not completely defined. In the present study, the effects of synthetic Pro ANF31-67 on renin secretion were examined in sodium-depleted, anesthetized dogs with a single intact kidney (n = 5).

METHODS

After 3 20-minute control renal clearance periods, synthetic dog Pro ANF31-67 was given intrarenally at a sustained dose of 0.03 microg/kg/min for 3 20-minute experimental intervals, and after discontinuation of the peptide infusion, 3 final 20-minute recovery periods were determined.

RESULTS

Sustained intrarenal infusions of the Pro ANF31-67 produced striking decrements (p<0.05) in renin secretion, from a control value of 1418 +/- 243 to 401 +/- 223 ng of angiotensin I/min. This 66% fall in renin secretion was associated with significant (P < 0.05) increases in creatinine clearance (40%), renal blood flow (8%), urine flow (50%), and sodium excretion (17%).

CONCLUSIONS

It is suggested that this inhibition of renin secretion was mediated, at least in part, in response to a ProANF31-67-induced increment in the sodium load delivered to the macula densa. An interaction of the peptide with the renal vascular receptor for suppression of renin release is also possible. ProANF31-67 may represent an important hormonal mechanism involved in the regulation of body-fluid balance.

Hemodynamic and renal effects of ProANF31-67 in hypertensive rats

It has been demonstrated previously that the atrial natriuretic factor prohormone fragment 31-67 (ProANF31-67) circulates in animals and possesses natriuretic and vasodilating actions. Although the plasma levels of the peptide are reportedly elevated in patients with high blood pressure, its role and actions in hypertension are unknown. In the present study, synthetic human ProANF31-67 was infused intravenously at doses of 0, 10, 30, and 100 ng/kg/min into respective groups of anesthetized normotensive and spontaneously hypertensive rats. Mean arterial pressure (MAP), urine flow rate (UV), and sodium excretion (UNaV) were measured during two consecutive 30-min periods. In both strains of rats, reductions in MAP with ProANF31-67 were similar in magnitude and dose-related. Sodium excretion responses to the peptide infusions also were remarkably similar in both normotensive and hypertensive rats, and the responses demonstrated 3- to 5-fold (P < 0.05) increments compared to control at the doses of 10 and 30 ng/kg/min. However, in the two strains of rats, attenuation of natriuresis occurred with the highest infusion dose of 100 ng/kg/min and was probably related to the large decreases in MAP of 17-23 mmHg at this dose of the peptide. The present results indicate the ProANF31-67 has important hemodynamic and renal effects in hypertension and may represent one compensatory mechanism involved in this disease.

The heartmate left ventricular assist system: first successful implantation in Missouri

We report a case of the first successful implantation of the HeartMate left ventricular assist system as a bridge to heart transplant in the state of Missouri. Indications, technique of insertion, patient selection, outcomes and future applications are discussed.