Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels

We propose a quantitative approach to probe the spatial heterogeneities of interactions in macromolecular gels, based on a combination of small angle X-ray (SAXS) and neutrons (SANS) scattering. We investigate the structure of model gluten protein gels and show that the gels display radically different SAXS and SANS profiles when the solvent is (at least partially) deuterated. The detailed analysis of the SANS signal as a function of the solvent deuteration demonstrates heterogeneities of sample deuteration at different length scales. The progressive exchange between the protons (H) of the proteins and the deuteriums (D) of the solvent is inhomogeneous and 60 nm large zones that are enriched in H are evidenced. In addition, at low protein concentration, in the sol state, solvent deuteration induces a liquid/liquid phase separation. Complementary biochemical and structure analyses show that the denser protein phase is more protonated and specifically enriched in glutenin, the polymeric fraction of gluten proteins. These findings suggest that the presence of H-rich zones in gluten gels would arise from the preferential interaction of glutenin polymers through a tight network of non-exchangeable intermolecular hydrogen bonds.

Pathophysiology and burden of infection in patients with diabetes mellitus and peripheral vascular disease: focus on skin and soft-tissue infections

Diabetes mellitus affects 284 million adults worldwide and is increasing in prevalence. Accelerated atherosclerosis in patients with diabetes mellitus contributes an increased risk of developing cardiovascular diseases including peripheral vascular disease (PVD). Immune dysfunction, diabetic neuropathy and poor circulation in patients with diabetes mellitus, especially those with PVD, place these patients at high risk for many types of typical and atypical infections. Complicated skin and soft-tissue infections (cSSTIs) are of particular concern because skin breakdown in patients with advanced diabetes mellitus and PVD provides a portal of entry for bacteria. Patients with diabetes mellitus are more likely to be hospitalized with cSSTIs and to experience related complications than patients without diabetes mellitus. Patients with PVD requiring lower extremity bypass are also at high risk of surgical site and graft infections. Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent causative pathogen in cSSTIs, and may be a significant contributor to surgical site infections, especially in patients who are colonized with MRSA on hospital admission. Patients with cSSTIs and diabetes mellitus or PVD experience lower clinical success rates than patients without these comorbidities, and may also have a longer length of hospital stay and higher risk of adverse drug events. Clinicians should be vigilant in recognizing the potential for infection with multi-drug-resistant organisms, especially MRSA, in these populations and initiating therapy with appropriate antibiotics.

Clinical and economic burden of invasive fungal diseases in Europe: focus on pre-emptive and empirical treatment of Aspergillus and Candida species

Invasive fungal diseases (IFDs) have been widely studied in recent years, largely because of the increasing population at risk. Aspergillus and Candida species remain the most common causes of IFDs, but other fungi are emerging. The early and accurate diagnosis of IFD is critical to outcome and the optimisation of treatment. Rapid diagnostic methods and new antifungal therapies have advanced disease management in recent years. Strategies for the prevention and treatment of IFDs include prophylaxis, and empirical and pre-emptive therapy. Here, we review the available primary literature on the clinical and economic burden of IFDs in Europe from 2000 to early 2011, with a focus on the value and outcomes of different approaches.

Health-related quality of life in patients with metastatic renal cell carcinoma treated with sunitinib vs interferon-alpha in a phase III trial: final results and geographical analysis

BACKGROUND

In a randomised phase III trial, sunitinib significantly improved efficacy over interferon-alpha (IFN-alpha) as first-line therapy for metastatic renal cell carcinoma (mRCC). We report the final health-related quality of life (HRQoL) results.

METHODS

Patients (n=750) received oral sunitinib 50 mg per day in 6-week cycles (4 weeks on, 2 weeks off treatment) or subcutaneous IFN-alpha 9 million units three times weekly. Health-related quality of life was assessed with nine end points: the Functional Assessment of Cancer Therapy-General and its four subscales, FACT-Kidney Symptom Index (FKSI-15) and its Disease-Related Symptoms subscale (FKSI-DRS), and EQ-5D questionnaire's EQ-5D Index and visual analogue scale. Data were analysed using mixed-effects model (MM), supplemented with pattern-mixture models (PMM), for the total sample and the US and European Union (EU) subgroups.

RESULTS

Patients receiving sunitinib reported better scores in the primary end point, FKSI-DRS, across all patient populations (P<0.05), and in nine, five, and six end points in the total sample, in the US and EU groups respectively (P<0.05). There were no significant differences between the US and EU groups for all end points with the exception of the FKSI item 'I am bothered by side effects of treatment' (P=0.02). In general, MM and PMM results were similar.

CONCLUSION

Patients treated with sunitinib in this study had improved HRQoL, compared with patients treated with IFN-alpha. Treatment differences within the US cohort did not differ from those within the EU cohort.

Quality of life (QOL) with sunitinib versus interferon-alfa (IFN-α) as first-line therapy in patients with metastatic renal cell carcinoma (mRCC): Final results

6529

Background: In an international, randomized phase 3 trial (Figlin et al, ASCO. 2008), sunitinib showed superior progression-free survival (the primary endpoint) and objective response rate over IFN-α (11 vs. 5 mo and 47% vs. 12%, respectively; p < 0.000001) as first-line mRCC therapy, with a median overall survival of more than 2 years. Here, we report the final health-related QOL results from this trial. Methods: 750 treatment-naïve mRCC patients were randomized 1:1 to receive sunitinib 50 mg orally once-daily in recurring cycles of 4 weeks on drug and 2 weeks off or IFN-α 9 MU subcutaneously thrice-weekly. QOL was measured by the Functional Assessment of Cancer Therapy-General (FACT-G), which has 4 subscales, the FACT-Kidney Symptom Index-15 item (FKSI-15), which includes a Disease-Related Symptoms (FKSI-DRS) subscale, and the EQ-5D questionnaire's utility index (EQ-5D Index) and visual analog scale (EQ-VAS). The primary QOL endpoint was FKSI-DRS. Higher scores indicated better outcomes. Patients completed questionnaires on days 1 and 28 of each cycle. Data were analyzed for the intent-to-treat population using mixed-effects models (MM), supplemented with pattern-mixture models (PMM). We also compared QOL of patients in the United States (US) with patients in the European Union (EU; France, Germany, Italy, Poland, Spain and United Kingdom). Results: Patients on sunitinib reported better FKSI-15 and FKSI-DRS scores than those on IFN-α, with a significant difference in the overall means across cycles (4.06 and 2.36, respectively; p < 0.0001; MM). Similarly, differences in means for FACT-G (and all subscales), EQ-5D Index, and EQ-VAS all significantly favored sunitinib (p < 0.05). Based on pre-set, required minimum score differences, between-treatment differences in the mean scores were clinically meaningful for FKSI-15, FKSI-DRS, FACT-G, and the FACT-G functional well-being subscale. Between-treatment differences were similar for both the US and EU populations. Across all analyses, results from PMM were similar to those from MM. Conclusions: Sunitinib provides superior QOL over IFN-α, in addition to superior efficacy, as first-line mRCC therapy.

[Table: see text]

Economic evaluation of sunitinib versus other new targeted therapies as first-line treatment of metastatic renal cell carcinoma (mRCC) in the United States

e17556

Background: RCC, the most prevalent kidney cancer, is a relatively rare malignancy that carries a poor prognosis. New targeted therapies, such as sunitinib, sorafenib, temsirolimus, and bevacizumab + interferon-alfa (IFN-α), are now available in the US for the treatment of mRCC. In the absence of head-to-head trials, the aim of this analysis was to assess the economic value of these therapies as first-line treatment of mRCC from a U.S. third-party payer perspective, using an indirect comparison based on reported survival data. Methods: An economic model was built to simulate progression-free and overall survival based on each treatment's hazard ratio against IFN-α as reported from phase II and III clinical trials. Clinical model parameters were also derived from these trials and complemented with clinical experts’ opinions. Costs of drugs, routine follow-up, treatment-related adverse events, disease progression, and best supportive care of terminally-ill patients were included in the model. Results, expressed as life-years (LY), progression-free LY (PFLY), and quality adjusted LY (QALY) gained, treatment costs (applied in 2008 USD), and incremental cost-effectiveness ratios (ICER), were obtained through probabilistic analysis over a 10-year time horizon. Since the phase III clinical trial of temsirolimus included the MSKCC (modified) poor risk group patients only, two separate evaluations were carried out: (1) comparison of sunitinib, sorafenib, and bevacizumab + IFN-α in all patients and (2) a similar comparison of sunitinib and temsirolimus in the poor-risk group patients only. Results: In the first comparison model, sunitinib was both more effective (with gains of 0.52 and 0.19 PFLY, and 0.17 and 0.03 QALY) and less costly (by $13,675 and $84,260) than sorafenib and bevacizumab + IFN-α, respectively, over 10 years. Similarly, sunitinib was both more effective (with gains of 0.12 PFLY and 0.07 QALY) and less costly (saving $9,605 over ten years) than temsirolimus in patients in the poor risk group. Conclusions: These model results suggest that sunitinib is a cost-effective alternative to sorafenib, bevacizumab + IFN-α, and temsirolimus as a first-line treatment of mRCC.

[Table: see text]

The epidemiologic, health-related quality of life, and economic burden of gastrointestinal stromal tumours

BACKGROUND AND OBJECTIVES

Gastrointestinal stromal tumours (GIST) are uncommon tumours believed to arise from interstitial cells of Cajal or their precursors in the gastrointestinal (GI) tract, accounting for a small percentage of GI neoplasms and sarcomas. Given the recent recognition of GIST as a distinct cancer, as well as new treatment options available today, a review of the epidemiologic, health-related quality of life (HRQL), and economic burden of GIST is timely from a payer, provider and patient perspective and may provide guidance for treatment decision making and reimbursement.

METHODS

A systematic literature review of PubMed and five scientific meeting databases, was conducted to identify published studies and abstracts describing the epidemiologic, HRQL and economic impact of GIST. Publications deemed worthy of further review, based on the information available in the abstract, were retrieved in full text.

RESULTS AND DISCUSSION

Thirty-four publications met the review criteria: 29 provided data on GIST epidemiology, one provided cost data, three reported HRQL outcomes, and one reported cost and HRQL outcomes. The annual incidence of GIST (cases per million) ranged from 6.8 in the USA to 14.5 in Sweden, with an estimated 5-year survival rate of 45-64%. On the Functional Illness of Chronic Therapy-fatigue instrument, GIST patients scored 40.0 compared with 37.6 in anaemic cancer patients (0 = worst; 52 = least fatigue). Total costs over 10 years for managing GIST patients with molecularly targeted treatment was estimated at pounds 47 521- pounds 56 146 per patient compared with pounds 4047- pounds 4230 per patient with best supportive care.

CONCLUSIONS

The incidence of GIST appears to be similar by country; the lower estimate in one country could be explained by differences in method of case ascertainment. Data suggest that the HRQL burden of GIST is similar to that with other cancers although this requires further exploration. The value of new therapies in GIST needs to consider not only cost but also anticipated benefits and the unmet medical need in this condition.

Economic evaluations of sunitinib versus interferon-alfa (IFN-α) in first-line metastatic renal cell carcinoma (mRCC)

6607

Background: A randomized phase III trial of sunitinib vs. IFN-a as first-line therapy for patients with mRCC is ongoing. An interim analysis of this study demonstrated superiority for the primary endpoint, progression-free survival (PFS), in the sunitinib arm vs. the IFN-a arm (median PFS = 11 months [95% CI: 10–12] vs. 4 months [95% CI: 4–6]; P<0.000001). Because of the clinical significance of these results, the objective of this study was to demonstrate the economic value of sunitinib vs. IFN-a in this setting from a US third-party payer perspective. Methods: Two Markov models with a 5- and 10-year time horizon were developed to evaluate the cost- effectiveness of sunitinib vs. IFN-a. The models projected survival and costs in 6-week cycles based on extrapolation of the trial survival data. Model 1 looked at first-line treatment followed by palliative care only, while Model 2 incorporated second-line treatment. Effectiveness was measured in terms of progression-free months (PFM) in Model 1, and life-years (LY) gained and quality adjusted life-years (QALY) gained in Model 2. Resource utilization included drugs, tests, scans, monitoring, physician visits, hospitalizations and treatment of adverse events. Costs and survival benefits were discounted annually at 3% and 5% in Model 1 and 2, respectively. All costs were adjusted to 2006 US dollars. Scenario and probabilistic sensitivity analyses were conducted. Results: Projected PFS and overall survival were longer for sunitinib than for IFN-a. The incremental cost-effectiveness ratios of sunitinib vs. IFN-a over 5- and 10-years were $7,769 and $7,782/PFM, respectively, in Model 1. Model 2 results at 10 years were $67,215/LY and $52,593/QALY gained. The key drivers of the model results were survival and sunitinib drug costs. Both models were robust in the tested scenarios. Conclusions: Both analyses found that sunitinib is a cost-effective alternative to IFN-a as first-line treatment in mRCC, with cost-effectiveness ratios within the established threshold that society is willing to pay for health benefits (i.e. $50,000–100,000/LY or QALY).

No significant financial relationships to disclose.

Quality of life (QOL) predicts for progression-free survival (PFS) in patients with metastatic renal cell carcinoma (mRCC) treated with sunitinib compared to interferon-alpha (IFN-α)

6594

Background: In a recent international, randomized phase III trial, sunitinib malate, an oral multitargeted receptor tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, RET and FLT3 with both antitumor and antiangiogenic effects, was associated with statistically superior clinical efficacy and superior health-related QOL vs. IFN-a as first-line therapy in patients with mRCC (Motzer et al, Proc ASCO 2006;24:2s [Abstract LBA3]). Here we report a substudy of baseline QOL variables predicting PFS. Methods: 750 mRCC patients were randomized 1:1 to receive either sunitinib 50 mg orally once daily in repeated 6-week cycles (4 weeks on treatment followed by 2 weeks off) or IFN-a (9 MU via subcutaneous injection 3 times weekly). QOL was measured by the Functional Assessment of Cancer Therapy-General (FACT-G), the FACT-Kidney Symptom Index's Disease-Related Symptoms subscale (FKSI-DRS), and the patient self-rated overall health state (EQ-VAS) from the EuroQol Group's EQ-5D self-report questionnaire. For all QOL endpoints, higher scores indicated better outcomes (better QOL or fewer symptoms). Cox proportional-hazards model was used to test which baseline QOL variables predict PFS while controlling for other baseline demographic and clinical factors as well as treatment. Because the three QOL scores are correlated (r=0.61–0.69), three separate univariate models were fitted. Results and Conclusions: All three baseline QOL variables were predictive of PFS: better baseline FACT-G, FKSI-DRS and EQ-VAS scores were associated with longer PFS. When QOL and other baseline variables were controlled in the models, the superior treatment effect of sunitinib on PFS remained robust and large (See the table below).

[Table: see text]

Functional dimorphism of two hAgRP promoter SNPs in linkage disequilibrium

The agouti related protein (AgRP) exerts its anabolic effects on food intake by antagonising the alpha-melanocyte stimulating hormone (alpha-MSH) at its receptors, melanocortin receptors 3 and 4 (MC3R and MC4R). A single nucleotide polymorphism (SNP) in the promoter of the human AgRP (hAgRP), -38C>T, was associated with low body fatness. The -38T allele that was associated with low body fatness also resulted in lower promoter activity. Here we report a novel SNP, -3019G>A, again in the promoter of hAgRP, which is in complete linkage disequilibrium (LD) with the -38C>T SNP (linked alleles: -3019A/-38T and -3019G/-38C). Functional analyses in a human adrenal and two mouse hypothalamus cell lines showed that the -3019A allele had significantly higher promoter activity. Hence, the two linked alleles (-3019A and -38T) had opposite effects on promoter function and yet they were both associated with low body fatness. The region encompassing the -38C>T SNP had approximately 1000-fold higher activity than the region encompassing the -3019G>A SNP, potentially determining the net functional effect between these two SNPs.

Early dialysis in a neonate with intrauterine lisinopril exposure

In general, angiotensin converting enzyme (ACE) inhibitors should be discontinued in pregnancy, as they can induce an ACE fetopathy. For the treatment of the latter, early peritoneal dialysis is recommended for in utero exposure to captopril and enalapril, although the outcome is poor. Early peritoneal dialysis has not previously been reported for lisinopril induced multiorgan failure. A case is reported in which treatment was given on postnatal day 3. The patient recovered from oligoanuria to almost normal renal function, and heart, brain, and musculoskeletal injury was reversible. This is despite relatively poor clearance of the drug through peritoneal dialysis. Analysis of the pharmacokinetic data suggests that haemodialysis or haemofiltration would be more efficacious for removal of the drug, and these treatments should be performed if available.

The interactions of amphotericin B with various sterols in relation to its possible use in anticancer therapy

Amphotericin B (AmB) is still the most common anti-fungal agent used to treat systemic fungal infections. It is known that this antibiotic acts by forming pores with the ergosterol contained in the membranes of fungi, but it also interacts with the cholesterol contained in the membranes of eukaryotic cells, hence its toxicity. AmB may also interact with the most common oxidation products of cholesterol found in vivo, together with interacting with biosynthetic precursors of cholesterol, namely, lanosterol and 7-dehydrocholesterol (7-DHC). The purpose of the present work was to study the interactions in solution between AmB and these various sterols, the techniques used being UV-Vis spectroscopy and differential scanning calorimetry. The results are globally interpreted in terms of the structural differences between the sterols. We show that AmB selectively interacts with 7-DHC which, according to a recent hypothesis proposed in the literature, has been identified in connexion with a therapeutic strategy against hepatocellular carcinomas. We find that the affinity of AmB towards 7-DHC is even greater than the affinity of the antibiotic towards ergosterol. We also find that AmB selectively interacts with the principal oxidation product of cholesterol, 7-ketocholesterol, a situation that has to be taken into account when AmB is administered.

Central 5-hydroxytryptamine-2A receptor expression in transgenic mice bearing a glucocorticoid receptor antisense

Transgenic mice bearing a transgene coding for a glucocorticoid receptor antisense mRNA that partially blocks glucocorticoid receptor expression were used to investigate the long-term effect of hypothalamic-pituitary-adrenal dysfunction on brain 5-hydroxytryptamine-2A (5-HT2A) receptor expression. The brain 5-HT2A receptor mRNA levels in transgenic mice were measured by in situ hybridization and compared to those in control mice. We also studied the effect of a 3-week treatment with fluoxetine on brain 5-HT2A receptor expression in the transgenic mice. No difference in 5-HT2A mRNA levels was observed between transgenic and control mice in cortical or striatal regions, and fluoxetine treatment was without effect. No difference in hypothalamic 5-HT2A mRNA levels was observed between transgenic and control mice, while fluoxetine treatment increased these levels in both transgenic as well as in the hypothalamic ventromedial and paraventricular nuclei of control mice. 5-HT2A receptor mRNA levels were similar in hippocampal CA1 and CA2 subregions of control and transgenic, but were lower in the CA3 and CA4 subregions of transgenic mice. Fluoxetine had no effect on 5-HT2A mRNA levels of transgenic mice but reduced control mouse 5-HT2A receptor mRNA levels in the CA3 subregion. These results suggest that impaired glucocorticoid receptor function can affect hippocampal 5-HT2A receptor expression in transgenic mice and that this is not corrected by fluoxetine treatment.

Effects of in ovo exposure to 2,3,7,8-TCDD on F1 generation adult chickens (Gallus gallus)

White Leghorn chickens (Gallus gallus) were used as surrogate species for the resident wild turkeys found on the Times Beach, Missouri, Superfund site. Parental chickens were injected with concentrations of 2,3,7,8-TCDD which modeled soil concentrations before (200 ppb) and after remediation (1ppb)[1]. Offspring were followed through development to assess alterations in reproductive maturity through the use of a four-way breeding study. F1 adult females exposed to a maternal dose of 8.6 ng/day began egg production approximately two weeks later than did F1 control adult females. By week eight, however, egg production between groups was equivalent. No differences were observed in eggshell gland estrogen or progesterone receptor levels.

Effects of environmentally relevant concentrations of 2,3,7,8-TCDD on domestic chicken immune function and CYP450 activity: F1 generation and egg injection studies

Domestic chickens (Gallus gallus) were used as a surrogate species for wild turkey to assess risk from environmental 2,3,7,8-TCDD exposure. Lymphocyte proliferation and CYP450 induction were assessed in adults exposed via i.m. injection, in F1 14-day old hatchlings, in F1 adults (30-weeks old), and in 14-day old hatchlings exposed via yolk sac injections. Hatchlings from injected eggs exhibited a dose-response in lymphocyte proliferation, IgM titers, EROD, and PROD endpoints. Exposed adults showed a significant dose-dependent increase in CYP450 induction. F1 14-day old chicks exhibited a significant dose-dependent suppression of B-cell proliferation and induction of CYP450 enzymes. F1 adult proliferative responses exhibited B-cell suppression, that was not statistically significant. Significant sex-dependent EROD and MROD induction was also observed in F1 adults, indicating mixed-function oxidase imprinting from maternal exposure.

Identification and immunolocalisation of annexins V and VI, the major cardiac annexins, in rat heart

OBJECTIVE

The heart contains proteins of the annexin family, a unique group of calcium binding proteins. This study was aimed at identifying the major cardiac annexins and determining their distribution in the rat heart.

METHODS

Annexins were isolated by affinity chromatography and purified by ion exchange high pressure liquid chromatography. Identification of isolated proteins by immunoblotting was confirmed by partial amino acid sequence determination. Antisera raised against the isolated proteins were used for immunohistochemistry by the avidin-biotin-peroxidase technique.

RESULTS

Two annexins were isolated and purified. Amino acid sequencing confirmed their identities as annexin V and VI. Immunohistochemistry showed that both annexins were present in cardiac myocytes and non-myocytes, but a distinct pattern of distribution was seen for each annexin. Annexin V immunoreactivity was enhanced in the atria compared with the ventricles, whereas annexin VI was more uniformly distributed. In individual cardiac myocytes annexin V was distributed throughout the cell by contrast with annexin VI, which localised to the sarcolemma. Intercalated discs displayed immunoreactivity for both annexins, most prominently for annexin VI. The most striking immunoreactivity for annexin V occurred in vascular endothelial cells, both in the microcirculation and in the major coronary vessels. Immunoreactivity for annexin VI in vascular structures was localised to the nuclei of endothelial and smooth muscle cells.

CONCLUSIONS

Annexins V and VI are the major cardiac annexins. The localisation of these annexins to different components of cardiac myocytes will serve to direct the search for their functions in the heart. The striking immunoreactivity for annexins, particularly annexin V, in the coronary vessels indicates that the functions of cardiac annexins include a role in the coronary circulatory system.

Rat brain natriuretic peptide is localized in atrial granules and released into the circulation

Rat brain natriuretic peptide (BNP) was detected by radioimmunoassay in heart atria and ventricles and in plasma. We have investigated its localization in atria and the possibility of cosecretion of atrial natriuretic factor (ANF) and BNP into the circulation. BNP was detected by chromatographic analysis and immunoblotting in the isolated atrial granules together with ANF: It consisted of two immunoreactive proteins of 14,000 and 2,500 apparent molecular weight. By immunohistochemical methods, BNP was particularly found in the perinuclear region of atrial cardiocytes. Double-labeling immunocytochemical methods colocalized BNP and ANF in the same atrial secretory granules. Basal plasma BNP levels ranged from 2.6 to 4.4 fmol/ml. After stimuli by morphine injection or an aortocaval shunt, BNP levels increased by 4- and 7-fold, respectively, whereas ANF levels rose by 50- and 6-fold, respectively. Depending on the stimulus, BNP release into the circulation is not necessarily proportional to ANF, indicating that BNP may originate not only from the atrial granules but also from other tissues such as the ventricles. These results suggest that BNP may participate with ANF in blood pressure control and salt and water homeostasis.

Ventricles as a major site of atrial natriuretic factor synthesis and release in cardiomyopathic hamsters with heart failure

The aim of the present study was to correlate in cardiomyopathic hamsters with congestive heart failure the levels of atrial and ventricular atrial natriuretic factor (ANF) messenger RNA (mRNA) with immunoreactive ANF (IR-ANF) plasma levels and the relative amount of IR-ANF released by the whole heart versus isolated ventricles in the Langendorff preparation. High-performance liquid chromatography analysis of the forms of ANF present in plasma and in the Langendorff effluent of whole heart versus isolated ventricles was also performed. As previously found for cardiac IR-ANF, the levels of ANF mRNA decreased gradually in atria and increased in an analogous fashion in ventricles with the severity of congestive heart failure. Plasma IR-ANF levels (C-terminal) were more elevated in moderate than in severe congestive heart failure, as were the IR-ANF levels in the Langendorff effluent of the whole heart. On the contrary, the effluent of isolated ventricles from animals in severe heart failure yielded more IR-ANF than that from hamsters in moderate heart failure. Thus, while the isolated ventricles from controls contributed 35.8% of IR-ANF released by the whole heart, ventricles from hamsters in moderate heart failure contributed 17.5%, and those from hamsters in severe heart failure contributed 73.9%. These results indicate that atrial cardiocytes contribute more IR-ANF than their ventricular counterpart in moderate heart failure and that ventricles are a major source of plasma IR-ANF in severe heart failure. Analysis of IR-ANF from plasma and the Langendorff effluent from whole hearts and isolated ventricles revealed that the ventricles are the major source of the propeptide (and of its cleaved products) found in the circulation of cardiomyopathic hamsters. These results suggest that ANF synthesis and secretion do not increase conjointly in atria but do increase in ventricles during congestive heart failure.

Atrial natriuretic factor in Purkinje fibers of rabbit heart

The Purkinje fibers of the rabbit false tendons (chordae tendineae spuriae) are endocrine cells containing immunoreactive atrial natriuretic factor (ANF) and ANF messenger RNA (mRNA). These cells, as visualized by immunocryoultramicrotomy, contain immunoreactive ANF in their secretory granules and their Golgi complex and exhibit ANF mRNA, as visualized by in situ hybridization with an ANF complementary RNA probe. The content of immunoreactive ANF and ANF mRNA of the Purkinje fibers is midway between that of atrial and ventricular working cardiocytes. High-pressure liquid chromatography analysis of immunoreactive ANF using antibodies against the C-terminal and N-terminal moieties of the molecule indicates that part of immunoreactive ANF contained in Purkinje fibers is the propeptide [Asn1,Tyr126]ANF whereas part was nonspecifically cleaved into C-terminal and N-terminal ANF. The chordae tendineae spuriae exhibit binding sites for ANF (Kd:approximately 1.0 nM; Bmax:approximately 2.3 fmol/mg). ANF profoundly decreases basal and stimulated (epinephrine, dopamine, isoproterenol, and forskolin) adenylate cyclase activity and cyclic adenosine monophosphate (AMP) levels. ANF has little effect on norepinephrine-stimulated adenylate cyclase activity or on norepinephrine-stimulated cyclic AMP levels. ANF produces only a slight increase in guanylate cyclase activity and cyclic guanosine monophosphate levels at high (10(7)-10(6) M) concentrations. These results suggest an autocrine function for ANF in the modulation of the impulse in the peripheral conduction cells (Purkinje fibers) of the rabbit through changes in second messenger levels.

Atrial natriuretic factor in the impulse-conduction system of rat cardiac ventricles

A complex network of atrial natriuretic factor-producing cells has been delineated by biochemical and morphological techniques in the rat ventricular myocardium. The chordae tendineae spuriae (CTS; false tendons) contain ANF mRNA and the ANF propeptide (Asn 1-Tyr 126) as assessed by Northern blot analysis, high-pressure liquid chromatography and immunohisto- and -cytochemistry, using three different affinity-purified antibodies: monoclonal and polyclonal antibodies against C-terminal ANF (Arg 101-Tyr 126) and polyclonal antibodies against N-terminal ANF (Asp 11-Ala 37). Two types of cells harboring ANF-containing secretory granules constitute the CTS: the majority (Purkinje type I) have ultrastructural similarities with both atrial and classical Purkinje fibers. Purkinje type-II fibers resemble working ventricular cardiocytes. Both cell types harbor a large paranuclear Golgi complex. The subendocardial Purkinje network is also made up of these two cell types. In this location, Purkinje type-I fibers form cable-like structures while Purkinje type-II fibers are either located beneath the former or abut directly on the endocardium. The latter are not separated from adjacent working ventricular cardiocytes by connective tissue septa. Coronary arteries and arterioles, as in birds, are surrounded by a cushion of Purkinje type-II fibers which blend with the surrounding myocardium. These results indicate that, in the rat, the entire intraventricular conduction system is constituted of endocrine cells producing ANF.

Validity and reliability issues in alternative patient classification systems

The validity and reliability issues involved in using alternative patient classification systems were reviewed. Disease Staging and Patient Management Categories (PMCs) were applied separately and in conjunction with DRGs to three populations of patients drawn from a nine-hospital community data base. Data were examined with analyses that were as consistent as possible with hospital-based reviews of resource utilization. Questions focused on content and context validity (partially assessable by homogeneity), general and statistical reliability (measured by variance reduction), gaming, and cost. Ordinal stratifications were inconsistently produced, and improvement to DRGs' homogeneity was generally negligible. When used alone, staging produced only half the variance reduction of DRGs. PMCs, when used alone, appeared to produce sizeable variance reductions that may have been due to the large number of one- and two-case categories produced. Staging had category overlap, was expensive, and was unidimensional and subject to manipulation. PMCs had potentially serious logic problems, and both were inadequately documented. Neither system was considered appropriate for all needs, but each might work adequately under well-defined and limited conditions.

A murine monoclonal antibody against rat atrial natriuretic factor (ANF) which cross-reacts with mouse ANF

A monoclonal antibody (MAb), 2H2, against rat synthetic atrial natriuretic factor (ANF) (Arg101-Tyr126) recognizes native ANF related peptides. The lack of reactivity of 2H2 with amino-terminal truncated ANF peptides implicates the two amino terminal arginine residues of ANF in the 2H2 epitope. Similarly, poor immunoreactivity of human ANF indicates the participation of isoleucine 110. Arginines 101 and 102 and isoleucine 110 may thus participate in a conformational epitope recognized by 2H2 or alternatively, substitution for, or elimination of these residues may alter the conformation of the 2H2 epitope. The MAb shows little cross-reactivity with extracts of rabbit atria but recognizes ANF related peptides in mouse and hamster atrial extracts. 2H2 also identifies immunoreactive ANF in histological sections of rat, mouse and hamster atria.

Internalization and lysosomal association of [125I]angiotensin II in norepinephrine-containing cells of the rat adrenal medulla

The morphological localization of [125I]angiotensin II (AII) in the rat adrenal medulla (AM) was studied by light- and electron-microscopic radioautography in vivo. With light microscopy the presence of binding sites for AII in both norepinephrine-containing (NE) and epinephrine-containing (E) cells was confirmed. With electron microscopy, it was found that AII binds to the cell surface of NE cells, is progressively internalized, and is associated with lysosomes and Golgi complex within 20 min, whereas in E cells AII seems to be internalized earlier and recycled back to the cell surface within 5 min without any appreciable association with intracellular organelles. These results suggest different intracellular pathways for AII in NE and E cells of the rat AM.

High Performance Liquid Chromatographic Determination of Seven Antioxidants in Oil and Lard: Collaborative Study

A high performance liquid chromatographic procedure for the determination of propyl gallate (PG), 2,4,5-trihydroxybutyrophenone (THBP), tert-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-buty1-4-hydroxyanisole (BHA), 2,6-di-tert-buty1-4-hydroxymethylphenol (Ionox-100), and 3,5-di-tert-buty1-4-hydroxytoluene (BHT) was collaboratively studied by 8 laboratories. The 14 samples analyzed consisted of 10 vegetable oil samples spiked in matched pairs at about 200,100, and 20ppm and 4 lard samples spiked in matched pairs at about 100 and 40 ppm for each antioxidant except NDGA which was spiked only at the 2 lower levels in oil. In the method studied, the samples were dissolved in hexane and the antioxidants were partitioned into acetonitrile. The acetonitrile was concentrated and diluted with isopropanol to give isopropanol-acetonitrile (1 + 1). The antioxidants were separated by reverse phase gradient elution and detected at 280 nm. The results from one laboratory were rejected as outlying and were not considered in any calculations. For the remaining 7 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, Ionox-100, and BHT were 93.2, 95.1,95.6,95.5,98.3,95.8, and 84.8%, respectively, and the overall mean coefficients of variation were 5.02,7.74, 19.3,4.36,3.75,6.33, and 3.45%, respectively.