Circadian rhythm of the soluble p75 tumor necrosis factor (sTNF-R75) receptor in humans--a possible explanation for the circadian kinetics of TNR-alpha effects

Circadian alterations of several immune functions in vivo are well established, and may have important physiological and clinical implications. In line with this, tumor necrosis factor (TNF)-alpha has been implicated in the circadian regulation of body temperature. As soluble TNF receptors (TNF-R) act as naturally occurring competitive inhibitors of this cytokine, we investigated plasma levels of the soluble sTNF-R55 and sTNF-R75 in comparison with plasma cortisol and body temperature in nine healthy male volunteers during a defined 16 h light/8 h dark cycle. It was found that sTNF-R75, but not sTNF-R55, exhibited a clear-cut circadian rhythm with a significant (P < 0.01) peak at 7:51 a.m. +/- 58 min. The phase of the sTNF-R75 rhythm preceded that of cortisol by approximately 1 h and inversely corresponded to the circadian rhythm of body temperature. Moreover, the individual amplitudes of sTNF-R75 and body temperature exhibited a significant (P < 0.01) positive correlation. These results suggest that (i) the two sTNF-R are regulated independently, (ii) the sTNF-R75 rhythm is not primarily due to the cortisol rhythm and (iii) the fluctuation of the sTNF-R may contribute to the regulation of body temperature by modulating the availability of free TNF.

The cost of treating hypertension: can we keep it under control without compromising the level of care?

The cost of hypertension treatment can be contained without compromising outcome. National recommendations for the routine diagnostic evaluation of hypertensive subjects do not include echocardiograms or ambulatory monitoring. These are expensive procedures, which, if performed in only a fraction of the total hypertensive population, would add several billion dollars to the cost of care. At present there are no data indicating that outcome of treatment would be improved. Costs of labeling before a definitive diagnosis is made, continuing lifestyle modification too long, medication switching, and not treating to goal blood pressures also increase cost without increased benefit. Although there are special indications for the more expensive newer medications, the majority of patients can be managed, at least initially, with less expensive therapies. Cost should not be a consideration, however, if one therapy has been shown to be more beneficial than another. Finally, the benefits of antihypertensive drug therapy have been underestimated because of the lack of consideration of prevention of left ventricular hypertrophy or progression to more severe disease by early treatment. On the other hand, the cost per quality of life-years saved has been overestimated. Pharmacoeconomic models may serve to mislead practitioners regarding treatment decisions.

In vivo retargeting of T cell effector function by recombinant bispecific single chain Fv (anti-CD3 x anti-idiotype) induces long-term survival in the murine BCL1 lymphoma model

As demonstrated in several preclinical models, bispecific Abs are attractive immunotherapeutic agents for tumor treatment. We have previously reported that a bacterially produced anti-CD3 x antitumor bispecific single chain variable fragment of Ab fragment (BsscFv), which is capable of retargeting CTLs toward BCL1 tumor cells, exhibits antitumor activity in vitro. To further facilitate BsscFv production, the coding sequence was subcloned in a eukaryotic expression vector and introduced into Chinese hamster ovary cells for large-scale production. In this report, we have determined the serum stability and the clearance rate from the circulation of BsscFv. Most important, we prove here the therapeutic value of BsscFv in the treatment of BCL1 lymphoma, a murine model for human non-Hodgkin's lymphoma. Tumor-bearing mice that were treated with rscFv in combination with staphylococcal enterotoxin B superantigen, human rIL-2, or murine rIL-12 showed long-term survival, whereas untreated mice all died. This is the first report of the successful in vivo use of BsscFv as an immunotherapeutic agent. Furthermore, long-term survival was the result of complete tumor removal and was not due to the induction of dormancy.

Carrier-induced, hapten-specific suppression: a problem of antigen presentation?

Prior immunity against a carrier protein has been shown to modulate the serologic response to injected haptens attached to the same carrier. In particular, a carrier/hapten-carrier immunization protocol induces marked suppression for IgG2a anti-hapten Ab production but does not interfere with anti-carrier Ab responses. Although the phenomenon of epitopic suppression has been amply demonstrated, the mechanism underlying the suppression remains unknown. The selective deficiency in IgG2a secretion suggests that IFN-gamma-producing Th1 cells are not properly activated. We and others have shown that the nature of the APCs present during the first encounter with the Ag influences the development of selected Th populations in vivo; dendritic cells (DCs) seem to be required for the induction of primary, Th1-type responses. Since carrier priming induces the clonal expansion of specific B cells that appear to efficiently capture the Ag, we hypothesized that the hapten-carrier conjugate may be presented by B cells in preimmunized animals. Therefore, we immunized mice to the conjugate by injecting syngeneic DCs pulsed in vitro with the Ag. Our data show that an injection of DCs and IL-12 prevents epitopic suppression, suggesting that it may result from defective Ag presentation.

Why are physicians not prescribing diuretics more frequently in the management of hypertension?

Diuretics have again been recommended by the Sixth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) as one of the first-choice medications in the management of hypertension. This recommendation is based on the results of numerous randomized, diuretic-based, long-term controlled clinical trials that have demonstrated a reduction in both cerebrovascular and cardiovascular morbidity. Despite this and other national recommendations, the use of diuretics has steadily decreased over the past 15 years. Reasons include heavy promotion of other medications and the perception that diuretics produce adverse metabolic effects and do not reduce coronary heart disease events. Data, however, indicate that (1) changes in glucose and cholesterol metabolism are minor, especially with the smaller doses now being used; (2) cardiovascular morbidity and mortality have been reduced in hypertensive patients, even in those with hyperlipidemia or diabetes, when diuretics are used; and (3) concerns about hypokalemia-induced arrhythmias have been overstated. While special indications exist for other medications in the treatment of hypertension, for example, use of an angiotensin-converting enzyme inhibitor (usually in addition to a diuretic) for a patient with heart failure or diabetic nephropathy, most patients, including those with hyperlipidemia or glucose intolerance, can be effectively treated with a diuretic as initial therapy or as part of a combination regimen. Diuretics should be used more not less frequently; use of diuretics would reduce the number of resistant hypertensive patients.

Garlic powder and plasma lipids and lipoproteins: a multicenter, randomized, placebo-controlled trial

BACKGROUND

Garlic powder tablets have been reported to lower serum cholesterol levels. There is widespread belief among the general public that garlic powder tablets aid in controlling cholesterol levels. However, much of the prior data demonstrating the cholesterol-lowering effect of garlic tablets involved studies that were inadequately controlled.

OBJECTIVE

To determine the lipid-lowering effect of garlic powder tablets in patients with hypercholesterolemia.

METHODS

This was a randomized, double-blind, placebo-controlled, 12-week, parallel treatment study carried out in 2 outpatient lipid clinics. Entry into the study after 8 weeks of diet stabilization required a mean low-density lipoprotein cholesterol level on 2 visits of 4.1 mmol/L (160 mg/dL) or lower and a triglyceride level of 4.0 mmol/L (350 mg/dL) or lower. The active treatment arm received tablets containing 300 mg of garlic powder (Kwai) 3 times per day, given with meals (total, 900 mg/d). This is equivalent to approximately 2.7 g or approximately 1 clove of fresh garlic per day. The placebo arm received an identical-looking tablet, also given 3 times per day with meals. The main outcome measures included levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol after 12 weeks of treatment.

RESULTS

Twenty-eight patients (43% male; mean +/- SD age, 58 +/- 14 years) received garlic powder treatment and 22 (68% male; mean +/- SD age, 57 +/- 13 years) received placebo treatment. There were no significant lipid or lipoprotein changes in either the placebo- or garlic-treated groups and no significant difference between changes in the placebo-treated group compared with changes in the garlic-treated patients.

CONCLUSION

Garlic powder (900 mg/d) treatment for 12 weeks was ineffective in lowering cholesterol levels in patients with hypercholesterolemia.

Nervousness and pain sensitivity: I. A positive correlation

Neuroanatomical studies suggest a close interrelationship between brainstem centers regulating arousal and pain sensitivity. Nervousness, as assessed with a Visual Analog Scale, and pain sensitivity, as assessed with a cold pressor test, were used to clarify whether a physiological association of nervousness and pain sensitivity can be found in healthy subjects. Forty healthy volunteers were included in the study. We demonstrate a significant positive correlation between self-rated nervousness and pain threshold. These data suggest that there is a coupling between nervousness and endogenous pain control. Based on the results, a nervousness-pain-threshold quotient was calculated as a possible measure of the interrelationship of the endogenous pain control system to autonomic activity. A different nervousness-pain-threshold quotient, indicating a different coupling, may provide information on changes in accessory neurophysiologic functions.

Nervousness and pain sensitivity: II. Changed relation in ex-addicts as a predictor for early relapse

We recently demonstrated a coupling between nervousness and pain sensitivity in healthy volunteers, and we defined a mean ratio of nervousness/log pain threshold of 1.95 +/- 1.47 for healthy humans. Because in another study former opiate addicts were found to exhibit a persistent opioid independent analgesia, we wondered whether nervousness is also changed in these patients, or if the balance between nervousness and pain sensitivity is altered. Forty unmedicated former opiate addicts during long-term rehabilitation and 40 age-matched control subjects were included in the study. The subjects rated their nervousness prior to a cold pressor test on a Visual Analog Scale. It turned out that the average nervousness rating was higher than in the control subjects and that a distinct subgroup of pain sensitive ex-addicts exhibited a higher ratio of nervousness vs. pain threshold. In this group the risk for relapse was three to four times higher than in the other ex-addicts.

The role of combination therapy in the treatment of hypertension

Only approximately 40% to 50% of hypertensive patients will achieve goal blood pressures of <140/ 90 mm Hg with monotherapy, regardless of the medication used. Fixed-dose combination therapy with two different classes of antihypertensive agents will achieve goal pressures in more than 70%. The sixth Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure has suggested that the use of combination therapy is appropriate as initial treatment. The advantages of combinations include: 1) greater blood pressure decrease and response rates than monotherapy; 2) fewer side effects with small doses of two drugs than with large doses of one agent; 3) improved adherence to treatment; and 4) possibly lower cost of therapy. Many different combinations of diuretics and beta-blockers, angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists, as well as ACE inhibitors and calcium antagonists are available. Two of these, Ziac and Capozide, have been approved as initial therapy. It is possible that the number of hypertensive individuals controlled at goal blood pressure levels will be increased if combination therapy is used as initial treatment.

Current recommendations for initial therapy in hypertension: are they still valid? Introduction

This symposium will address questions regarding current recommendations for initial therapy in the management of hypertension: Are we treating too many hypertensive patients or too few? When do we start treatment with medications and what medications should we use? Professor Lawrence Ramsay from England will discuss the concept of absolute versus relative risk and review the long-term hypertension treatment trials and what they have and have not told us. Dr. Michael Weber of New York will discuss some newer data on angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, and calcium channel blockers and attempt to answer the question: are these data sufficient to warrant recommending these agents as initial therapy? Finally, Dr. Henry Black of Chicago and I will update a new-old concept: is it time to consider low-dose fixed combination therapy as initial treatment in hypertension?

[Biological activity of E. coli expressed BMP-4]

BMP-4 is physiologically present in low concentrations in human bone matrix. So far the protein has only been produced in small quantities by expression in mammalian cell cultures. In this study we investigated the biological activity of E. coli-expressed BMP-4. In vitro neonatal rat muscle tissue was incubated together with BMP-4 during 4 h, followed by an incubation period of 14 days on cellulose acetate membranes in BMP-free medium. The addition of 0.4 microgram BMP-4 induced cartilage formation in 1/8 samples while 4 micrograms BMP-4 showed chondroneogenesis in 2/10 samples. When the BMP-4 concentration was increased to 40 micrograms, new cartilage formation was seen in 5/7 samples. In vivo BMP-4 was implanted intramuscularly for 3 weeks in ICR mice. Amounts of 10 micrograms rhBMP-4 and more (up to 100 micrograms) constantly induced heterotopic ossicle formation. BMP-4 was also combined with a collagen carrier and implanted for 2 and 4 weeks in the abdominal muscle of SD rats. While 0.4 microgram BMP-4 showed no bone or cartilage formation, the amount of 40 micrograms BMP-4 showed new heterotopic cartilage formation, followed by endochondral ossification in almost all samples. The results prove that E. coli-expressed BMP-4 possesses the same inductive properties as mammalian-cell-expressed BMP-4.

Dendritic cells fused with mastocytoma cells elicit therapeutic antitumor immunity

Characterization of the spontaneous immune response that frequently occurs in tumor-bearing animals, as well as immunization using dendritic cells pulsed with tumor antigens, suggests that a limiting factor of the tumor-specific immune response may be a defect in the co-stimulatory signal that is required for optimal activation of T cells. In this work, we describe a new approach to improve the antigen-presenting capacity of tumor cells, which does not require a source of purified tumor-associated antigen. We fused P815 mastocytoma cells with bone marrow-derived dendritic cells. We obtained one hybrid that displayed the phenotypic and functional properties of dendritic cells and expressed mRNA coding for the tumor-associated antigen P815 A/B. Injections of irradiated hybrid cells prevented the growth of preimplanted mastocytoma and induced long-lasting tumor resistance.

Dendritic cells fused with mastocytoma cells elicit therapeutic antitumor immunity

Characterization of the spontaneous immune response that frequently occurs in tumor-bearing animals, as well as immunization using dendritic cells pulsed with tumor antigens, suggests that a limiting factor of the tumor-specific immune response may be a defect in the co-stimulatory signal that is required for optimal activation of T cells. In this work, we describe a new approach to improve the antigen-presenting capacity of tumor cells, which does not require a source of purified tumor-associated antigen. We fused P815 mastocytoma cells with bone marrow-derived dendritic cells. We obtained one hybrid that displayed the phenotypic and functional properties of dendritic cells and expressed mRNA coding for the tumor-associated antigen P815 A/B. Injections of irradiated hybrid cells prevented the growth of preimplanted mastocytoma and induced long-lasting tumor resistance.

Bdellastasin, a serine protease inhibitor of the antistasin family from the medical leech (Hirudo medicinalis)--primary structure, expression in yeast, and characterisation of native and recombinant inhibitor

We have reported earlier the isolation and amino acid composition of bdellin A from medical leech, and characterised it as an inhibitor of trypsin, plasmin and acrosin [Fritz, H., Gebhardt, M., Meister, R. & Fink, E. (1971) in Proceedings of the international research conference on proteinase inhibitors (Fritz, H. & Tschesche, H., eds) pp. 271-280, Walter de Gruyter, Berlin]. In the present study, one of several chromatographic forms of this inhibitor was isolated from a semi-pure preparation. Elucidation of its amino acid sequence revealed that bdellin A is a member of the antistasin family. Therefore, it was renamed bdellastasin to avoid confusion with bdellin B, which is another trypsin-plasmin inhibitor from the medical leech, but of the Kazal type. Furthermore, a synthetic gene of bdellastasin was constructed, and the protein expressed in Saccharomyces cerevisiae with yields of 29 mg/l. The recombinant bdellastasin was purified by hydrophobic interaction and anion-exchange chromatography. Comparison by mass spectroscopy, far-ultraviolet circular dichroism studies, sequence determination, and inhibition characteristics demonstrated the identity of recombinant and native bdellastasin. The Ki values of bdellastasin for inhibition of bovine trypsin and human plasmin are in the nanomolar range; no inhibition was detected for factor Xa, thrombin, tissue kallikrein, plasma kallikrein and chymotrypsin. Circular dichroism analyses indicated that bdellastasin is devoid of secondary-structural elements.

The host range and interference properties of two closely related feline leukemia variants suggest that they use distinct receptors

The proviral clones 61E and 61C represent two closely related variants of feline leukemia virus (FeLV) that exhibit significant differences in their biological and pathogenic properties. The major pathogenic determinant has been mapped to the extracellular envelope glycoprotein (Env-SU), but the mechanism by which envelope differences influence pathogenesis is not well understood. Moreover, it is unclear whether these viruses infect the same target cells and/or enter cells using the same receptor. In the present study, we exploited a recently developed single cycle infection assay to examine the host range and interference properties of 61E and 61C FeLVs and found that these two FeLV variants differ significantly in their host ranges and receptor usages. FeLV-61C was found to be an ecotropic virus; the entry of viruses bearing a 61C envelope protein (Env-SU) into cell lines was limited to feline T-cells and feline fibroblasts. In contrast, the host range of 61E includes, in addition to all feline cells examined, some canine, murine, and human cell lines. Feline fibroblast and feline T-cells that expressed 61E envelope were resistant to infection with a virus bearing a 61E Env-SU, whereas these same cells were susceptible to infection by an otherwise similar virus pseudotyped with the 61C Env-SU. This pattern of interference was observed in cells expressing 61E envelope alone, in the absence of other FeLV gene products, demonstrating that interference was mediated specifically by Env-SU. Fibroblast cells chronically infected with a 61C virus were partially resistant to infection with a virus having a 61C Env-SU, but were not resistant to infection by a virus having a 61E Env-SU. On the basis of the current understanding of virus-receptor interactions, the lack of interference between 61E and 61C under conditions where there is significant homologous interference, combined with the differences in their host cell range, leads us to conclude that 61E and 61C use two distinct primary cellular receptors for entry.

Increased heart rate in depressed subjects in spite of unchanged autonomic balance?

A clinical study was conducted to examine the effects of depression on cardiac autonomic control. Cardiac autonomic control was measured in 26 nonmedicated patients (19 females) suffering from Major Depression, melancholic type, and in 26 age- and sex-matched normal controls. We measured heart rate and high frequency heart rate variability (respiratory sinus arrhythmia), pulsewave velocity and blood pressure, during 10 min of supine rest under controlled conditions. Using a log transformed time domain measure of respiratory sinus arrhythmia (logRSA), we found an inverse linear dependence between cardiac vagal tone and age in the healthy subjects as well as the depressed patients. logRSA was 0.22+/-0.25 in the patients and 0.25+/-0.16 in the control group. While this difference was not significant (P > 0.1), the deviations from the regression line were significantly (P < 0.0005) greater in the patients (0.21+/-0.12) than in the control group (0.09+/-0.07), indicating a more heterogeneous vagal tone in the depressed patients. Heart rate was also significantly (P < 0.03) greater in the depressed patients (76.6+/-12.4) than in the control group (69.5+/-6.9). No between-group differences were found in pulsewave velocity or systolic blood pressure, but diastolic blood pressure was lower in depressed patients (73.5+/-8.7 vs. 80.8+/-9.1). We discuss the possibility that the increased heart rate seen in the absence of vagal tone changes may not be due to altered vagal or sympathetic tone, as measured in this study. Other factors, including altered autonomous heart rate, may be responsible for the higher heart rate in the depressed group.

The immune response induced in vivo by dendritic cells is dependent on B7-1 or B7-2, but the inhibition of both signals does not lead to tolerance

Dendritic cells (DC) can be used as physiological adjuvant in vivo. Indeed, a single injection of DC, pulsed in vitro with antigen, induces activation of specific T and B lymphocytes in syngeneic mice. The unique capacity of DC to sensitize naive T lymphocytes correlates with elevated expression of MHC antigens as well as co-stimulatory molecules. The aim of this work was to evaluate the functional role of the individual CD28 ligands in the induction of primary humoral and cellular responses, and to characterize the nature of the immune response induced in the presence of selected co-stimulatory molecules. Our data show that the primary response is strictly B7 dependent, and that B7-1 and B7-2 mediate overlapping co-stimulatory functions, as either molecule alone is sufficient to initiate an immune reaction. Inhibition of B7-1 and B7-2, however, does not lead to tolerance as predicted by the two-signal hypothesis. Rather, recognition of antigen in the absence of B7 appears as a null event, since subsequent immunogenic stimulation results in a primary response. Blockade of B7-2 co-stimulatory molecules significantly inhibits antigen-specific IgG1 but not IgG2a production, suggesting that B7-2 may direct the development of Th2 cells. These data emphasize the critical role of the CD28/B7 pathway in the induction of the immune response by DC, which appear to be the initiating antigen-presenting cells in situ.

Femtosecond diode-pumped Nd:glass laser with more than 1 W of average output power

We have demonstrated 175-fs pulses with 1 W and 300-fs pulses with 1.2 W of average output power at a pulse repetition rate of 117 MHz from a Nd:phosphate (Schott LG 760) glass laser pumped by a 1-cm-wide, 20-W diode laser bar. Stable soliton mode locking was achieved by use of an intracavity semiconductor saturable absorber mirror. We obtained more than 2 W of average power without mode locking. Using cylindrical cavity mirrors, we adapted the laser mode inside the Nd:glass to the highly elliptical pump beam in both dimensions (tangential and sagittal axes) while maintaining a nearly ideal circular TEM(00) output beam with M(2) approximately 1.2 . Overpumping the laser mode in the tangential plane and efficient unidirectional heat removal in the sagittal plane using a 0.8-mm thin Nd:glass also contributed to the good output-beam quality.

Fine mapping of the autosomal recessive polycystic kidney disease locus (PKHD1) and the genes MUT, RDS, CSNK2 beta, and GSTA1 at 6p21.1-p12

A total of 33 polymorphic markers were analyzed to generate a high-resolution genetic linkage map of the locus PKHD1 (polycystic kidney and hepatic disease 1) for the autosomal recessive polycystic kidney disease (ARPKD), using a combination of recombination mapping and linkage analysis in 164 families. Recombinants narrowed the PKHD1 region from 3.8 cM to a 1-cM interval flanked by the markers D6S1024 and D6S1714. Linkage disequilibrium analysis in 13 Finnish ARPKD families identified two different highly conserved haplotypes with four distal flanking markers, suggesting the existence of at least two major mutations of Finnish origin. The genes MUT (methylmalonyl coenzyme A-mutase), RDS (retinal degeneration, slow), CSNK2 beta (casein kinase II, beta subunit), and GSTA1 (glutathione S-transferase alpha, type 1) were excluded as PKHD1 genes using both established and novel intragenic polymorphisms in families with key recombinants. These genetic data, combined with our YAC-based physical map of the 6p21-p12 region, will facilitate efforts to positionally clone the PKHD1 gene.

Efficient and tunable diode-pumped femtosecond Yb:glass lasers

Diode-pumped Yb:phosphate and Yb:silicate glass lasers have been passively mode locked for the first time to the authors' knowledge. Reliable self-starting mode locking without critical cavity alignment has been achieved with intracavity semiconductor saturable-absorber mirrors and soliton mode locking. We generated pulses as short as 58 fs with the Yb:phosphate laser and 61 fs with the Yb:silicate laser at average output powers of 65 and 53 mW, respectively. The pulse repetition rate was 112 MHz. Additionally, we demonstrated tunability of femtosecond pulses from 1025 to 1065 nm for the Yb:phosphate and from 1030 to 1082 nm for the Yb:silicate glasses. The highest mode-locked output power was 405 mW, with 183-fs pulses from the phosphate glass. The diode pump power was 1.68 W, corresponding to 24% optical-to-optical efficiency. The highest cw output power was 510 mW at the same incident pump power.

Interleukin-12-activated natural killer cells recognize B7 costimulatory molecules on tumor cells and autologous dendritic cells

Activation of natural killer (NK) cells in the presence of interleukin-12 (IL-12) augments the capacity of these effector cells to recognize B7-1- and B7-2-expressing target cells. These effector cells also efficiently lyse autologous B7-positive progenitor or organ-derived dendritic cells, suggesting a physiologic regulatory pathway between IL-12, NK cells, and B7-expressing antigen-presenting cells. Although IL-12-activated NK cells secreted higher levels of interferon-gamma, this cytokine did not play a role in synergistic effects of IL-12 and B7 on NK activation. The B7-counterreceptor was found to be selectively upregulated on IL-2/IL-12 as compared with IL-2-activated NK cells. CD28 is functionally involved in the recognition of B7 on target cells since IL-2/IL-12-activated NK cells derived from CD28 knockout mice were strongly reduced in their capacity to lyse syngeneic B7-positive tumor cells as well as antigen-presenting cells. However, recognition of B7 on allogeneic targets did not require the expression of CD28 on the IL-2/IL-12-activated NK cells. Hence, IL-12 triggers the expression of both CD28-dependent and CD28-independent mechanisms that allow NK cells to eliminate B7-positive target cells including autologous dendritic cells.

Autonomic regulation of circulation and cardiac contractility during a 14-month space flight

The space flight of physician cosmonaut V.V. Polyakov, the longest to date (438 days), has yielded new data about human adaptation to long-term weightlessness. Autonomic regulation of circulation and cardiac contractility were evaluated in three experiments entitled Pulstrans, Night, and Holter. In the Pulstrans experiment electrocardiographic (ECG), ballistocardiographic (BCG), seismocardiographic (SCG), and some other parameters were recorded. In the Night experiment, only the ballistocardiogram was recorded, but a special feature of this experiment is that the BCG records were obtained with a contactless method. This method has several advantages, the most important of which are the possibility of studying slow-wave variations in physiologic parameters (ultradian rhythms) on the basis of recordings made under standard conditions over a prolonged period. The Holter experiment (24-hour electrocardiographic monitoring) used a portable cardiorecorder (Spacelab, USA). The obtained electrocardiographic data were used to analyze heart rate variability. In the first 6 months of the 14-month flight, the dynamics of cardiovascular parameters in V.V. Polyakov was virtually the same as in the other cosmonauts. The data obtained after the first 6 months of Polyakov's sojourn in space are unique and mention should be made of at least three important aspects: (1) activation of a new, additional adaptive mechanism in the 8th-9th months of flight, as is evidenced by alterations in the periodicity and power of superslow wave oscillations (ultradian rhythms) reflecting the activity of the subcortical cardiovascular centers and of the higher levels of autonomic regulation; (2) growth of cardiac contractility accompanied by a decrease in heart rate during the last few months of flight; (3) a considerable increase in the daily average values of absolute power of heart rate's variability MF component, which reflects the activity of the vasomotor center. Specific mechanisms of adaptation to weightless conditions appear to be associated with activation of higher autonomic centers. The hypothesis that central levels of circulation regulation are activated in a long-term space flight was investigated by analyzing of ultradian rhythms in nighttime. The data, received during the flight of V. V. Polyakov, show, that the process of human adaptation to long influence of weightlessness consists of a number of consecutive stages, during which the activation of more and more high levels of control system of physiological functions occurs.

Results of therapy with carvedilol, a beta-blocker vasodilator with antioxidant properties, in hypertensive patients

Carvedilol is a new beta-blocker antihypertensive agent with vasodilating properties secondary to alpha 1-blocking activity. Peripheral vascular resistance is reduced and cardiac output and renal function are not altered with carvedilol. The antihypertensive effects of this agent are equivalent to those of other beta-blockers, calcium channel blockers, angiotensin converting enzyme inhibitors, and diuretics. Carvedilol has a neutral effect on lipids and glucose metabolism. The percentage of responders is increased when carvedilol is combined with a diuretic. This agent has several unique properties. In addition to its antihypertensive effects, carvedilol in vitro and in vivo has been shown to have antiproliferative effects on smooth muscle cells and to inhibit the action of oxygen-free radicals. The antioxidant properties of this compound are significantly greater than those of vitamin E. In animal models, carvedilol may slow the process of atherogenesis, reduce infarct size, and improve postinfarction survival to a greater degree than other beta-blockers. Recent studies have demonstrated that carvedilol reduces morbidity and mortality in patients with congestive heart failure who are already receiving angiotensin converting enzyme inhibitors, diuretics, and digitalis. The antioxidant and antiproliferative activities of carvedilol may present an advantage over other available antihypertensive medications.