Role of the EEG theta network during software production: a connectivity study

Software programming is an acquired evolutionary skill originating from consolidated cognitive functions (i.e., attentive, logical, coordination, mathematic calculation, and language comprehension), but the underlying neurophysiological processes are still not completely known. In the present study, we investigated and compared the brain activities supporting realistic programming, text and code reading tasks, analyzing Electroencephalographic (EEG) signals acquired from 11 experienced programmers. Multichannel spectral analysis and a phase-based effective connectivity study were carried out. Our results highlighted that both realistic programming and reading tasks are supported by modulations of the Theta fronto-parietal network, in which parietal areas behave as sources of information, while frontal areas behave as receivers. Nevertheless, during realistic programming, both an increase in Theta power and changes in network topology emerged, suggesting a task-related adaptation of the supporting network system. This reorganization mainly regarded the parietal area, which assumes a prominent role, increasing its hub functioning and its connectivity in the network in terms of centrality and degree.

No Difference in Muscle Basal Oxygenation in a Bedridden Population Pre and Post Rehabilitation

Long periods of bed rest for elderly population, due to a femur fracture event, can cause a deterioration in the muscular capacity. Therefore, monitoring of the muscle oxidative capacity in this fragile population is necessary to define the muscular oxidative metabolism state before and after a rehabilitation period. The time-domain near-infrared spectroscopy (TD-NIRS) technique enables the absolute values to be calculated for hemodynamic parameters such as oxy- (O2Hb), deoxy- (HHb), total- (tHb) haemoglobin, and tissue oxygen saturation (SO2) of the muscular tissue. In this work, we have characterized vastus lateralis muscle hemodynamics during a baseline period at two different time points: after the surgery (PRE) and after 15 days of rehabilitation (POST). The mean values for the absolute values of the hemodynamic parameters were: O2Hb_PRE = 49.1 ± 14.1 μM; O2Hb_POST = 47.1 ± 13.4 μM; HHb_PRE = 28.3 ± 10.3 μM; HHb_POST = 26.7 ± 9.9 μM; tHb_PRE = 77.3 ± 23.6 μM; tHb_POST = 73.8 ± 21.4 μM; SO2_PRE = 63.9 ± 4.0% and SO2_POST = 64.9 ± 5.6%. The hemodynamic parameters did not show significant differences at both group and single subject level. These results suggest that for this kind of population, the baseline of the hemodynamic parameters is not the best one to consider to assess the rehabilitation progresses in terms of muscular oxidative metabolism.

Monitoring the haemodynamic response to visual stimulation in glaucoma patients

In this paper, we used time-domain functional near infrared spectroscopy (TD-fNIRS) to evaluate the haemodynamic response function (HRF) in the occipital cortex following visual stimulation in glaucomatous eyes as compared to healthy eyes. A total of 98 subjects were enrolled in the study and clinically classified as healthy subjects, glaucoma patients (primary open-angle glaucoma) and mixed subjects (i.e. with a different classification for the two eyes). After quality check data were used from HRF of 73 healthy and 62 glaucomatous eyes. The amplitudes of the oxygenated and deoxygenated haemoglobin concentrations, together with their latencies with respect to the stimulus onset, were estimated by fitting their time course with a canonical HRF. Statistical analysis showed that the amplitudes of both haemodynamic parameters show a significant association with the pathology and a significant discriminating ability, while no significant result was found for latencies. Overall, our findings together with the ease of use and noninvasiveness of TD-NIRS, make this technique a promising candidate as a supporting tool for a better evaluation of the glaucoma pathology.

Sustained fatigue assessment during isometric exercises with time-domain near infrared spectroscopy and surface electromyography signals

The effect of sustained fatigue during an upper limb isometric exercise is presented to investigate a group of healthy subjects with simultaneous time-domain (TD) NIRS and surface electromyography (sEMG) recordings on the deltoid lateralis muscle. The aim of the work was to understand which TD-NIRS parameters can be used as descriptors for sustained muscular fatigue, focusing on the slow phase of this process and using median frequency (MF) computed from sEMG as gold standard measure. It was found that oxygen saturation and deoxy-hemoglobin are slightly better descriptors of sustained fatigue, than oxy-hemoglobin, since they showed a higher correlation with MF, while total-hemoglobin correlation with MF was lower.

Pulse transit time measured by photoplethysmography improves the accuracy of heart rate as a surrogate measure of cardiac output, stroke volume and oxygen uptake in response to graded exercise

Heart rate (HR) is a valuable and widespread measure for physical training programs, although its description of conditioning is limited to the cardiac response to exercise. More comprehensive measures of exercise adaptation include cardiac output (Q̇), stroke volume (SV) and oxygen uptake (V̇O2), but these physiological parameters can be measured only with cumbersome equipment installed in clinical settings. In this work, we explore the ability of pulse transit time (PTT) to represent a valuable pairing with HR for indirectly estimating Q̇, SV and V̇O2 non-invasively. PTT was measured as the time interval between the peak of the electrocardiographic (ECG) R-wave and the onset of the photoplethysmography (PPG) waveform at the periphery (i.e. fingertip) with a portable sensor. Fifteen healthy young subjects underwent a graded incremental cycling protocol after which HR and PTT were correlated with Q̇, SV and V̇O2 using linear mixed models. The addition of PTT significantly improved the modeling of Q̇, SV and V̇O2 at the individual level ([Formula: see text] for SV, 0.548 for Q̇, and 0.771 for V̇O2) compared to predictive models based solely on HR ([Formula: see text] for SV, 0.503 for Q̇, and 0.745 for V̇O2). While challenges in sensitivity and artifact rejection exist, combining PTT with HR holds potential for development of novel wearable sensors that provide exercise assessment largely superior to HR monitors.

The effects of consuming eggs for lunch on satiety and subsequent food intake

The aim of the present work was to investigate the effects of eggs consumed for lunch on satiety, satiation and subsequent energy intake at the next meal. Thirty-one healthy male and female subjects participated in a randomized, three-way, crossover study. Following consumption of a standard breakfast, participants were asked to consume three isocaloric test lunches: omelette, jacket potato and chicken sandwich. Subjective measures of satiety were recorded using visual analog scales at regular intervals throughout the day. Energy intake at the next meal was assessed 4 h after lunch with an ad libitum meal. The egg lunch showed a significantly stronger satiating effect compared with the jacket potato meal. No effect on energy intake was seen. These data indicate that consumption of an omelette meal consumed at lunch could increase satiety to a greater extent than a carbohydrate meal and may facilitate reduction of energy consumption between meals.

Venous thromboembolism in patients hospitalized in internal medicine wards

Venous thromboembolism (VTE) is one of the main causes of morbility and mortality in the ospedalized patients. Epidemiologist studies have also demonstrated that VTE is an important and frequent problems in medical patients. In surgical patients is done with greater frequency, but in medical patients prophylaxis is not completely codified and less often less practiced. This review shows epidemiological data, risk factors and classification of the risk of VTE in patients with medical pathologies. Then meta-analyses studies and main studies such as Medenox, Prevent and Artemis, that have examined the prophylaxis of VTE in medical patients are described and discussed, along with their results concerning morbility and mortality. The current problems of prophylaxis in medical patients are reviewed , such as duration of treatment, optimal dosage of the low molecular weight heparin (LMWH) and the correct risk assessment of VTE. EXCLAIM Study has showed the benefit of extended prophylaxis with statistically significant reduction in VTE events.

Study of neurovascular and autonomic response in a divided attention test by means of EEG, ECG and NIRS signals

We evaluated neurovascular and autonomic response to a Divided Attention task within a group of 16 healthy subjects, by means of Electroencephalography, Electrocardiography, functional Near Infrared Spectroscopy techniques, acquired simultaneously. We exctracted Alpha (8-13,5 Hz) and Beta (13,5-30 Hz) power rhythms with a spectral autoregressive residual model, and inter-beat-interval (RR series) and separated superficial (extracortical) and depth NIRS contribution. Cross Correlation Function at different time lags was then calculated between each signal and the task, modeled as a square wave and among couples of signals, in order to evaluate the sequence of activation of the different physiological districts involved and the common information shared. Results showed the presence of a cascade of responses and a strong influence by the block task on each signal, representative of the neurovascular coupling elicited by the cognitive cerebral activation.

Tomato consumption and plasma lycopene concentration in people aged 65 y and over in a British national survey

OBJECTIVE

Assessment of consumption of raw and processed tomatoes, plasma lycopene concentration and their interrelationship in a nationally representative sample of elderly British people.

SETTING

: A 1994-1995 National Diet and Nutrition Survey: a nationwide cross-sectional sample of people aged 65 y and over living in mainland Britain, either in the community ("free-living", n=1275) or in institutions such as nursing homes (n=412).

METHODS

Consumption of raw and processed tomatoes (including those in tomato-containing composite foods) was recorded by a 4-day dietary record for each participant. Plasma lycopene concentration was assayed by HPLC. Sociodemographic and lifestyle information was recorded by trained interviewers.

RESULTS

In all, 29% of free-living people and 24% of those living in institutions did not consume any raw or processed tomatoes during the 4-day recording period. Free-living participants were more likely to consume raw tomatoes (26 vs 16%). Plasma lycopene concentration was positively associated with the weight of raw and processed tomatoes consumed, especially with processed tomatoes and their products, alcohol consumption and with plasma total (as well as HDL and non-HDL) cholesterol concentrations. Among free-living participants, increased age, cigarette smoking habit and manual occupational social class were all associated with lower plasma lycopene concentration.

CONCLUSIONS

In the current population, consumption of raw and processed tomatoes varied by sociodemographic and lifestyle characteristics, and made a significant contribution to plasma lycopene concentration. Determinants of plasma lycopene concentration were age, plasma cholesterol concentration and smoking habit.

[Thrombosis of great pulmonary vessels causing severe pulmonary hypertension in systemic lupus erythematosus]

We describe a 34 year old male patient with systemic lupus erythematosus (SLE) who developed pulmonary hypertension (PHT) associated with anticardiolipin antibodies. Ten years after diagnosis, an helical CT scan revealed thrombosis of the major pulmonary arteries, which was confirmed by digital pulmonary angiography. An inferior caval vein filter was placed and oral anticoagulation was begun. The patient refused pulmonary thromboendarterectomy and died soon thereafter. Even though PHT is widely described associated with SLE, proximal thrombosis of pulmonary arteries is exceptional. We describe such a patient review the different etiologies, incidence and diagnostic approach of PHT in SLE, focusing on those patients with an effective treatment.

Isomerization of lycopene in the gastric milieu

There is considerable interest in the bioavailability of carotenoids from the diet and their bioactivity in vivo. Little is known, however, of the preabsorption events in the gastric lumen on the breakdown or isomerisation of dietary carotenoids. In this study the effects of the acidic environment found in the gastric milieu on lycopene have been investigated. The results show that under these conditions all-trans-lycopene is isomerised to cis-isomers, which may be implicated in enhanced absorption from the small intestine. Furthermore the pH, as well as the food matrix, seems to have an influence on the level of isomerisation of this carotenoid.

Combined quality improvement ratio: a method for a more robust evaluation of changes in screening rates

INTRODUCTION

It has been proposed that a ratio of the discordant cells from a McNemar's Chi-square table be used as a measure of quality improvement, and that this measure be called the Quality Improvement Ratio (QuIR). As proposed, patients enrolled in only one year of a two-year study are excluded from the McNemar's table of the QuIR. Since the original proposal of the McNemar's Chi-square in 1947 included application to matched pair data, a more comprehensive analysis would be possible if the single-year enrollees were matched into pairs.

METHODS

Patients enrolled in only the first study year are matched and paired with patients enrolled in only the second study year. The pairs are matched on variables important to the disease or process being evaluated. The matched pairs are combined with the repeatedly measured subjects to increase the statistical power of the analysis. The Combined Quality Improvement Ratio (CQuIR) is demonstrated with parameters from the original articles, in a--Markov chain Monte-Carlo simulation, so a direct comparison can be made.

RESULTS

CQuIR improved statistical power, especially in simulations of small populations. In some simulations the statistical power was double that of the QuIR alone.

DISCUSSION

Although the QuIR provides important information, the CQuIR allows more of the data to be used to evaluate the effect of interventions in policy, delivery, and practice. The increase in statistical power of the CQuIR over the QuIR can facilitate successful evaluation of health care services.

DISTRIBUTION OF LIPID-SOLUBLE ANTIOXIDANTS IN LIPOPROTEINS FROM HEALTHY SUBJECTS. I. CORRELATION WITH PLASMA ANTIOXIDANT LEVELS AND COMPOSITION OF LIPOPROTEINS

The concentration of five lipid-soluble antioxidants (gamma- and alpha-tocopherol, lycopene, beta-carotene and ubiquinol-10) was measured in plasma and very low-density, low-density and high-density lipoproteins (VLDL, LDL and HDL) isolated from young healthy normo- cholesterolemic subjects. Alpha-tocopherol was the exclusive antioxidant whose plasma concentration significantly correlated with the absolute concentration of total cholesterol (r =0.541, P<0.001). No correlation was found between plasma concentration and lipoprotein content of alpha-tocopherol and ubiquinol-10, whereas it reached statistically significant values for gamma-tocopherol, lycopene and beta-carotene. The alpha-tocopherol content in VLDL and HDL, but not in LDL, was strictly associated with the relative abundance of cholesterol and phospholipids in the lipoprotein particles. Moreover, the difference between alpha-tocopherol concentration in VLDL and LDL appeared to be strictly related to the differences in cholesterol, phospholipids and triglycerides. The percent distribution of the total plasma pool of antioxidant in each lipoprotein class revealed that gamma- and alpha-tocopherol were roughly equally distributed in LDL and HDL. On the other hand, lycopene, beta-carotene and ubiquinol-10 were preferentially sequestered in LDL. Finally, the absolute and relative concentration of alpha-tocopherol, but not that of other antioxidants, in HDL exhibited a statistically significant correlation with plasma HDL/LDL cholesterol ratio. These findings indicate that: (i) plasma concentrations of major lipid-soluble antioxidants are not always predictive of their levels in lipoproteins and that, within individual lipoprotein classes, (ii) the lipid composition, metabolism and relative plasma concentration may significantly affect their abundance. 2000 Academic Press@p$hr Copyright 2000 Academic Press.

DISTRIBUTION OF LIPID-SOLUBLE ANTIOXIDANTS IN LIPOPROTEINS FROM HEALTHY SUBJECTS. II. EFFECTS OF IN VIVO SUPPLEMENTATION WITH alpha-TOCOPHEROL

The effects of orally supplemented dl -alpha-tocopherol on the plasma concentration of lipid-soluble antioxidants and their distribution in very-low-density, low-density and high-density lipoproteins (VLDL, LDL and HDL) was investigated in a cohort of control normocholesterolemic adult subjects receiving 600 mg alpha-tocopherol daily for 2 weeks. This regimen did not modify the plasma lipid profile (total, LDL and HDL cholesterol and triglycerides) and chemical composition of VLDL, LDL and HDL. Plasma concentration of alpha-tocopherol increased from 19.44+/-4.77 to 38.03+/-9.06 µm and this was associated with slight decrease in the concentration of gamma-tocopherol from 1.27+/-0.97 to 0.99+/-1.17 µm, without any significant changes of either lycopene and beta-carotene. Qualitatively similar changes were found in VLDL, LDL and HDL but the net increase of alpha-tocopherol in plasma did not correlate with the increase in alpha-tocopherol content in any of the lipoprotein types. Following supplementation, the percentage of total plasma alpha-tocopherol pool carried by VLDL increased from 20.97+/-6.07% to 33.57+/-6.97%, whereas it decreased from 41.85+/-7.02% to 36.36+/-5.69% in the case of LDL and from 37.17+/-6.04% to 30.05+/-4.88% in the case of HDL. The absolute and relative enrichment of alpha-tocopherol in either VLDL and LDL did not exhibit any statistically relevant correlation with the chemical composition of these lipoproteins in the different subjects investigated. On the other hand, the amount of alpha-tocopherol enriching the HDL particles was inversely related to the relative abundance of protein (r =0.449;P<0.05) and directly to the phospholipid/protein ratio (r =0.480, P<0.05). 2000 Academic Press@p$hr Copyright 2000 Academic Press.

The nature of intracrine peptide hormone action

Current theory holds that peptide hormone action results from hormone binding to cell-surface receptors, with the generation of intracellular second messengers. However, a growing body of evidence suggests that intracellular peptide hormone, either internalized or synthesized in situ, can exert physiologically relevant effects. These effects are diverse and poorly understood. I propose that such intracrine action can serve to modulate cellular function over time and thereby play a role in biological memory of various sorts, in the maintenance of hormonal responsiveness, and in cellular differentiation.

Antioxidant activity applying an improved ABTS radical cation decolorization assay

A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems.

Macromolecular carbonyls in human stratum corneum: a biomarker for environmental oxidant exposure?

The presence of stratum corneum carbonyls may serve as an intrinsic dosimeter for environmental oxidative damage to skin. To investigate the accumulation of carbonyls in human stratum corneum, skin was tape-stripped, then tapes were sequentially incubated with 2,4-dinitrophenyl hydrazine (DNPH), rat anti-DNP, mouse anti-rat IgG conjugated with alkaline phosphatase, p-nitrophenyl phosphate and absorbance (405 nm) measured and carbonyls estimated. Stratum corneum exposed in vitro to oxidants: hypochlorous acid (1, 10, 100 mM), ozone (0, 1, 5, 10 ppm for 2 h) or UV light (280-400 nm; 0, 4, 88, or 24 J/cm2) contained increased carbonyls. Furthermore, stratum corneum carbonyls were elevated in tanned compared with untanned sites: dorsal hand (0.43 +/- 0.06 nmol/cm2) vs. lower arm (0.32 +/- 0.04, mean +/- S.E.M., n = 11; P < 0.003) and lower back (0.26 +/- 0.02) vs. buttock (0.21 +/- 0.02; n = 6, P < 0.01) indicating in vivo oxidative damage.

Antioxidant reactions of all-trans retinol in phospholipid bilayers: effect of oxygen partial pressure, radical fluxes, and retinol concentration

Lipoperoxyl radical-scavenging activity of retinol in unilamellar soybean phosphatidylcholine liposomes was studied under a variety of conditions to appreciate to what extend retinol may be considered an effective antioxidant. Peroxidation, initiated by 2 mM 2,2'-azobis(amidino-propane)hydrochloride (AAPH), was carried out at 160 torr O2 or at 15 torr O2, in the absence or in the presence of 10 to 40 mM retinol. As evaluated by the length of the inhibition periods, t(inh), and by the ratio between the inhibition and propagation rate, R(inh)/R(p), the antioxidant activity of retinol was higher at 15 torr O2 than at 160 torr O2. The consumption rate of retinol was markedly faster at 160 torr O2 than at 15 torr O2 and increased with the increase of retinol concentration under both oxygen tensions. When liposome peroxidation was carried out under N2, retinol consumption was independent of retinol concentration. Peroxyl radicals oxidize retinol to 5,6-retinol epoxide. The ratio between 5,6-epoxide formed and the retinol consumed was markedly higher at 15 torr O2 than under air and decreased with the increased retinol concentrations. When butylated hydroxytoluene was included into the liposomal suspension, most of the consumed retinol was converted into 5,6-epoxide. Liposomes were incubated at 15 torr O2, in the presence of 0.5 to 10 mM AAPH. The antioxidant effectiveness of 40 mM retinol, as measured by the R(inh)/R(p) ratio, increased with the increase of the radical fluxes. The results suggest, besides radical trapping, that a major consumption of retinol during lipid oxidation occurs through self-oxidation reactions, which are concentration- and oxygen-dependent. A decreased self-oxidation makes retinol a better lipoperoxyl radical scavenger at low, rather than at high partial pressure of oxygen. However, when self-oxidation of retinol is prevented, only a minor fraction of the antioxidant is allowed to effectively act as a radical scavenger, suggesting that the radical-trapping reactions are rate-limiting for the antioxidant process. Peroxyl radical concentration, by shifting the route of the retinol activity toward radical scavenging, brings about an increasingly more efficient radical trapping. It is concluded that all-trans retinol behaves as a more effective antioxidant at low oxygen partial pressure, low retinol concentrations, and high radical flux.

Comparing comorbid-illness indices assessing outcome variation: the case of prostatectomy

OBJECTIVE

We investigated and compared the effects of three different comorbid indices on selection of procedure and outcome variation to determine which, if any, could be used for interpreting outcomes data.

DESIGN

Retrospective cohort study.

SETTING

Large multispecialty group practice.

PATIENTS

Patients (aged 55-85 years) with residence in the United States who underwent a first-time prostatectomy for benign prostatic hyperplasia: 302 total; 253 transurethral procedures (TURF) versus 49 open procedures (OP).

MEASUREMENTS AND MAIN RESULTS

The following indices were used to assess comorbid disease: Charison index (CI), index of coexistent disease (ICED), and Kaplan-Feinstein index (KFI). The main outcome measure was the five-year mortality rate. The unadjusted five-year mortality rates were 16% (40/ 253) for TURP and 4% (2/49) for OP; survival analysis revealed this difference to be marginally significant at the p = -05 level. In an effort to control for the effect of comorbidity, CI, ICED, and KFI were independently assessed: together with age, they each had similar effects in rendering the risk of death associated with procedure type insignificant. However, comorbidity, as derived with ICED (not CI or KFI), was identified as a confounding variable when assessing the five-year mortality rate after prostatectomy as ICED was associated with the procedure type (predictor variable) and the five-year mortality (outcome variable).

CONCLUSION

Differences in the composition and scoring of comorbid indices may have important implications for interpreting outcomes data. Nevertheless, these results, together with those of previous studies, suggest that the reported increased mortality for patients undergoing TURP is probably due to case-mix differences.

Multilayer perceptrons to approximate complex valued functions

In this paper the approximation capabilities of different structures of complex feedforward neural networks, reported in the literature, have been theoretically analyzed. In particular a new density theorem for Complex Multilayer Perceptrons with complex valued non-analytical sigmoidal activation functions has been proven. Such a result makes Multilayer Perceptrons with complex valued neurons universal interpolators of continuous complex valued functions. Moreover the approximation properties of superpositions of analytic activation functions have been investigated, proving that such combinations are not dense in the set of continuous complex valued functions. Several numerical examples have also been reported in order to show the advantages introduced by Complex Multilayer Perceptrons in terms of computational complexity with respect to the classical real MLP.

Reciprocal protective effects of all-trans retinol and alpha-tocopherol during lipid peroxidation in retinal membranes

Interactions between vitamin A and vitamin E in suppressing lipid peroxidation were observed in bovine retinal membrane preparations submitted to peroxidative injury by the water soluble azo initiator 2,2'-azobis(2-amidino-propane) hydrochloride (AAPH). Incorporation of 0.75 nmol mg prot(-1) all-trans retinol, an amount comparable with that of the endogenous alpha-tocopherol, significantly elongated the induction time preceding the release of TBA-reactive lipid peroxidation products, and reduced the consumption rate of the endogenous alpha-tocopherol. On the other hand, all-trans retinol was not able to induce any delay to the onset of lipid peroxidation when incorporated in membranes deprived of endogenous alpha-tocopherol by exposure to UV light, although TBARS produced within 60 min decreased slightly. Consumption of all-trans retinol during peroxidation was more rapid when all-trans retinol was incorporated in membranes deprived of alpha-tocopherol than in native membranes. These data suggest that reciprocal protective effects between vitamin A and vitamin E may strongly contribute to the defence of membranes against oxidative stress.

Vitamin A preserves the cytotoxic activity of adriamycin while counteracting its peroxidative effects in human leukemic cells in vitro

Previous results from our laboratory gave evidence that safe doses of vitamin A were very effective in protecting rats from adriamycin-induced oxidative stress and lethal cardiotoxicity (Tesoriere, L. et al. (1994) J. Pharmacol. Experim. Ther. 269, 430-436). This was an incentive also to evaluate whether or not vitamin A affected the antitumor activity of adriamycin. K562 human erythroleukemia cells were exposed to adriamycin or to adriamycin plus vitamin A. Presence of 2.5 to 15 microM all-trans retinol in the cell culture did not impair the cytotoxicity of adriamycin. Rather, an enhanced cell death was observed when cell colony was exposed to both compounds. Additional assays showed that all-trans retinol counteracted the lipoperoxide formation, assayed as malondialdehyde, induced in cell cultures by the redox cycling activity of adriamycin. These data strongly encourage a new therapeuthical approach with safe doses of vitamin A as an adjuvant in cancer chemotherapy.

Angiotensin and the regulation of cellular growth. Pathophysiologic implications for cardiovascular and noncardiovascular tissues

Components of the renin-angiotensin system can be found in the vasculature, although in most cases it is unclear how much, if any, of this renin in the vasculature is locally synthesized. Over recent years, a variety of novel actions of angiotensin II have been delineated which suggest that in appropriate physiologic or pathologic circumstances vascular angiotensin II can play an important role in determining vascular structure. Moreover, angiotensin II may play a role in neoplastic growth of vascular and nonvascular tissues.

New approaches to the study of the cellular biology of the cardiovascular system

Recent findings suggest that the local renin-angiotensin systems, locally generated catecholamines, and possibly other locally generated peptides interact in a complex fashion to regulate the cellular biology of the myocardium, the vascular wall, and other tissues. New evidence indicates that the components of the renin-angiotensin system are synthesized in cardiovascular tissues, that the synthesis of these components can be modulated by pharmacologic agents, and that angiotensin II, the effector protein of the renin system, appears to be capable of producing hypertrophy or hyperplasia in specific tissues. In addition, recent studies suggest the participation of enhanced proto-oncogene transcriptional activity in the development of hyperplasia and hypertrophy in cardiovascular tissue. Taken together, these data raise the possibility that angiotensin and perhaps other components of the renin system can be viewed as locally active growth factors capable of acting in a fashion similar to that associated with cytokines in other systems.

The myocardial intracellular renin-angiotensin system

In recent years several tissues have been found to contain the components of the renin-angiotensin system. Locally synthesized renin could conceivably function in an endocrine, paracrine or autocrine manner. Isolated left ventricular cardiac myocytes of the rat were examined in the present study and renin and angiotensin II were detected in these cells. This observation suggests the existence of a functioning renin-angiotensin system in the heart and, more particularly, in the left ventricular cardiac myocyte. Additional evidence, derived from micrococcal nuclease and deoxyribonuclease I treatment of angiotensin II-exposed chromatin, suggests that angiotensin II could subserve an intracellular function in some of its cells of synthesis.

A simplified radioimmunoassay for physiologically active angiotensin peptides [(1-8) octa- and (2-8) heptapeptides]

The availability of a sensitive and highly specific rabbit antiserum and the development of a peptide-extraction method employing glass beads permitted the evolution of a rapid reliable radioimmunoassay that measures the sum of the concentration of angiotensin II and its active metabolite, angiotensin III. At a dilution of 1:32,000 the antiserum is capable of measuring 1 fmol (1 pg) of angiotensin II. Cross reactivities of this antiserum, taking angiotensin II as 1.0, are: angiotensin III, 0.75; angiotensin-(3-8) hexapeptide, 0.11; angiotensin I, 0.006; angiotensin-(1-14) tetradecapeptide, 0.0001. The recovery of angiotensin II added to hormone-free plasma was 73 +/- 2% [mean +/- standard deviation (SD), n = 20]. When 0.9 ml of plasma was extracted, the minimal concentration of angiotensin II and III that could be quantified was 4 fmol/ml. When larger volumes of plasma were extracted, sensitivity was enhanced. Plasma blanks were zero. Intra-assay variability was 7.6% SD and interassay variability was 11.7% SD. Angiotensin II and III concentration in venous plasma of normal volunteers on an ad libitum diet was 15 +/- 8 fmol/ml (mean +/- SD, range less than 4 to 35 fmol/ml). The plasma of a patient with primary aldosteronism had an unmeasurable value (less than 4 fmol/ml). Posture, converting enzyme inhibition, and renal artery stenosis resulted in expected changes of angiotensin concentration.

Effect of angiotensin II on RNA synthesis by isolated nuclei

Peptide hormones are known to bind to cell surface receptors as the first step in the generation of their effects on target tissues. However, it remains uncertain whether internalized hormone might also play a role in the production of longterm or trophic effects of peptide hormones. Because the peptide hormone angiotensin II appears to be internalized by target cells, we studied the effect of this peptide on isolated hepatic nuclei. At both 5 X 10(-7)M and 5 X 10(-9)M, angiotensin II significantly increased RNA synthesis. This effect was not mimicked by Sar1-Ala8-angiotensin II (saralasin) or the unrelated nonapeptide teprotide.

Selectivity of angiotensin II antisera

A significant problem in the immunoassay of angiotensin II is the cross-reactivity of most available antisera with the peptide's metabolic products, (des-Asp1)-angiotensin II and (des-Asp1.Arg2)-angiotensin II. In order to attempt to generate antisera of greater selectivity, a variety of conjugates between angiotensin II or derivative peptides and carrier proteins were examined as immunogens with the aim of generating antisera that would selectively identify the amino terminal region of the peptide. Selectivity for the amino terminus was achieved by either (1) immunization with N-acetylated angiotensin II-amide which had been coupled to rabbit serum albumin by its carboxy terminus, or (2) immunization with angiotensin-(1-7)-heptapeptide which was randomly coupled to thyroglobulin. The antisera produced with the N-acetylated immunogen cross-reacted with the unacetylated ligand (Asn1-Val5)-angiotensin, but did not recognize the human hormone (Asp1,Ile5)-angiotensin. Carboxy-terminal coupling of angiotensin without N-acetylation did not induce selectivity for the amino terminus, nor did a conjugate which was linked to the carrier protein via a diazo bond to His6 of the peptide. These findings may be explained by the fact that N-acetylated angiotensin II resists degradation by amino peptidases and thus retains its structure in the immunogen and by the fact that the (1-7)-heptapeptide has lost the immunodominant carboxy-terminal epitope, thus emphasizing the desired amino terminal determinant.

Pulmonary hypertrophic osteoarthropathy in a child with late-onset agammaglobulinemia

A case of hypertrophic osteoarthropathy is described in an 8-year-old child with late-onset agammaglobulinemia, bronchiectasis and clubbing of the fingers and toes. The child presented with pain of recent onset in the legs, ankles, and knees and a diagnosis of hypertrophic osteoarthropathy was made on the basis of the radiologic findings. Therefore the differential diagnosis of bone and joint pain in agammaglobulinemic subjects must take into account hypertrophic osteoarthropathy.

Renin synthesis by canine aortic smooth muscle cells in culture

Angiotensin-I generating activity has been detected in homogenates of arterial tissue but it remains unclear whether this enzymatic activity results from the presence of renin itself or from the action of other proteases such as cathepsin D. In an assay system employing anephric dog plasma as substrate and buffered to pH 7.4, we detected angiotensin-I generating activity in homogenates of canine aortic smooth muscle cells. This enzymatic activity was in large part inhibitable by renin-specific antisera raised to pure canine renal renin. Immunofluorescent study of cultured arterial smooth muscle cells was also performed using renin specific antiserum. Granular cytoplasmic immunofluorescence was detected when specific antirenin serum was used but not when preimmune serum was employed. The addition of pure canine renin to the renin antiserum during staining suppressed the granular immunofluorescence confirming the specificity of staining. Finally, biosynthetic radiolabelling studies were performed. Immunoprecipitation of newly synthesized proteins with antirenin serum and staphylococcal protein A followed by gel electrophoresis and autoradiography demonstrated the synthesis of an immunoreactive protein with the molecular weight of renin. Pretreatment of the antirenin serum with pure canine renin resulted in the disappearance of this immunoreactive protein band. Thus these studies provide multiple lines of evidence to indicate the in situ synthesis of renin by vascular smooth muscle cells.

Studies on two novel angiotensin II actions

Animal data suggest that angiotensin II may directly affect renal sodium retention independent of aldosterone (4,6). Additionally there is evidence to suggest that the hormone can stimulate protein synthesis in a variety of tissues and that indeed it may be a vasculotoxin (5,7). We describe here experiments designed to elucidate the role of angiotensin II in renal sodium retention in normal man. Additionally we present preliminary evidence suggesting that unlike the rapid sodium retaining effect, some delayed (trophic) actions of the hormone may be generated by a hitherto unappreciated mechanism.

Golgi-ANAE positivity in leukemic blast cells: a possible T-suppressor cell leukemia

Different patterns of acid alpha-naphthyl-acetate esterase (ANAE) positivity in lymphocytes have been related to distinct functional lymphocyte subpopulations. A case of T-ALL with a cytochemical and immunological phenotype consistent with a T-suppressor cell leukemia is reported. In particular a specific pattern of Golgi-ANAE positivity is probably characteristic of TG cells, which include a subset with suppressor function.

Dissociation of renin--aldosterone and renal prostaglandin E during volume expansion induced by immersion in normal man

The relationship of the renin--angiotensin--aldosterone axis with renal prostaglandin E is complex. Although studies have suggested that these two hormonal systems respond to experimental manipulations in a parallel manner, their interdependence has not been assessed fully during volume expansion. Since studies have demonstrated that in normal man the central hypervolaemia induced by water immersion to the neck produces a prompt and profound suppression of plasma renin activity and plasma aldosterone concentration without concomitant alteration of plasma composition, immersion afforded a unique opportunity to assess simultaneously the effects of central hypervolaemia on plasma renin activity, plasma aldosterone concentration and prostaglandin E excretion. 2. Seven normal subjects were studied twice while in balance on a diet containing 10 mmol of sodium/day, 100 mmol of potassium/day: with indomethacin administration (50 mg given every 6 h for five doses) and without indomethacin. Urinary prostaglandin E excretion was measured hourly and plasma renin activity and plasma aldosterone concentration at 30 min intervals. 3. Immersion was associated with a marked suppression of plasma renin activity (59 +/- 7%) and plasma aldosterone concentration (55 +/- 3%) with a return to pre-study values during the recovery hour. Concomitantly, urinary prostaglandin E excretion increased from 4.7 to a peak of 10.9 ng/min. Although administration of indomethacin lowered the basal rate of urinary prostaglandin E excretion and plasma renin activity, it did not prevent the subsequent augmentation of urinary prostaglandin E or the suppression of plasma renin activity and plasma aldosterone during the subsequent 4 h of immersion. 4. These results demonstrate a dissociation of renin--aldosterone and prostaglandin E during hypervolaemia and suggest that whereas prostaglandin E may constitute one of the major determinants of renin release clinically and experimentally, these two hormonal systems can be dissociated from each other in response to central volume expansion in man.

Strongyloides stercoralis in Papanicolaou-stained smears of ascitic fluid

Filariform larvae of Strongyloides stercoralis were found by cytologic examination in Papanicolaou-stained smears of ascitic fluid in a renal transplant recipient treated with immunosuppressive drugs. The patient developed a fatal hyperinfection of S. stercoralis produced by an autoinfective cycle of the parasite.

Inhibition of angiotensin-converting enzyme for diagnosis of renal-artery stenosis

To determine its utility as an aid in diagnosis of renovascular hypertension, we administered nonapeptide converting-enzyme inhibitor (CEI) (which inhibits conversion of angiotensin I to angiotensin II) (0.25 mg per kilogram) to 14 unselected hypertensive patients undergoing bilateral renal-vein catheterization. In seven (Group I) predominantly unilateral disease was discovered by angiography (renal-artery stenosis in six and hydronephrosis in one); in the remaining seven (Group II) no rennal-artery abnormality was found. In Group I, mean (+/- S.E.) ratio of involved to uninvolved renal-vein plasma renin activity (PRA) increased from 2.94 +/- 0.91 before to 8.36 +/- 2.94 after CEI (P less than 0.01). In Group II, the ratio (of the initially higher to the lower side) was 1.99 +/- 0.49 before and 1.17 +/- 0.07 after CEI (P greater 0.02). Post-CEI PRA was predicted by pretreatment PRA. Mean blood pressure fell in both groups after CEI, and the decrement was predicted by pre-CEI PRA. These data suggest that CEI can be of use at the time of renal-vein catheterization, serving to increase diagnostic accuracy by increasing the difference in PRA between the two sides when there is unilateral disease.

Volume as a determinant of plasma aldosterone in anephric man

Previous studies from this laboratory have demonstrated that the redistribution of blood volume and concomitant central hypervolemia induced by water immersion to the neck (NI), produces a prompt and profound suppression of plasma renin activity (PRA) and plasma aldosterone concentration (PA) without concomitant alterations in serum sodium and potassium concentrations. The NI model was utilized to assess the responsiveness of PA to volume expansion in 12 anephric subjects. The patients were studied on 2 occasions, 48 h after their last dialysis: during a seated control study (7 of the patients) and during 3 h of NI (all 12 patients). The conditions of seated posture and time of day were identical. Blood for PRA, PA, and cortisol was obtained at 30-min intervals for 5 h. PRA was undetectable in all patients. NI failed to alter PA. Plasma cortisol declined progressively throughout NI; serum potassium concentration remained unchanged. An identical NI study in normal subjects suppressed PA by 60%. These data demonstrate that when plasma composition and posture are maintained constant, marked central hypervolemia does not alter PA in anephric man. The present findings support the role of the renin-angiotensin system as the prepotent mediator of volume-induced changes in PA.

Effect of dichloromethane diphosphonate on calcium homeostatic mechanisms in pregnant cows

The administration of 4 mg/kg/day of dichloromethane diphosphonate (Cl2MDP) subcutaneously to pregnant cows fed a low-calcium diet significantly reduced bone resorption as indicated by microradiographic evaluation of endosteal surfaces of cross sections of ribs. Plasma parathyroid hormone levels were similar between Cl2MDP-treated and control cows prepartum, during EDTA infusions, and near parturition. Ultrastructurally, chief cells of the parathyroid glands of both groups of cows were in the active stage of the secretory cycle. The chronically stimulated chief cell from cows administered Cl2MDP had a large cytoplasmic area containing many lipofuscin granules and lysosomal bodies and a few secretory granules near the large Golgi apparatus or aligned along the plasma membrane. Uptake of calcium 45 by the duodenal mucosa incubated in vitro was greater in Cl2MDP-treated cows compared to control cows. The administration of Cl2MDP significantly reduced rapidly mobilization calcium reserves. Following an intravenous EDTA infusion and the spontaneous calcium drain associated with parturition and the beginning of lactation, Cl2MDP-treated cows developed severe hypocalcemia. The rapid mobilization of calcium reserves in cows administered Cl2MDP prepartum was impaired mainly because of diminished resorption of bone despite adequate parathyroid hormone secretion in response to severe postpartal or EDTA-induced hypocalcemia.