[Effect of progressive insulin resistance on the correlation of glucose metabolism and bone status]. / A progrediáló inzulinrezisztencia hatása a glükózanyagcsere csontállapot kapcsolatokra.

A paradox is hidden in the increasing number of patients with insulin resistance, Type 2 diabetes and osteoporosis, as the world wide diabetes epidemic is driven by the same obesity which protects the bones in the obese females. Our aim was to investigate the connection between the early glucose intolerance, insulin resistance and bone density and metabolism. After metabolic status of matched 20 healthy and 51 glucose intolerant women (age: 49 +/- 9 y.) was determined, hyperinsulinemic-euglycemic clamps were done, while adipo- and cytokine levels were measured. Bone mineral density over lumbar spine and the femur neck were measured by DEXA. No differences in bone density were observed between groups at any sites measured. Tight correlations were found between total body glucose utilization and bone density in healthy group (lumbar spine r = -0.4921, p < 0.05, femur neck: r = -0.4972, p < 0.05), while with deterioration of glucose metabolism this correlation disappeared (lumbar spine: r = -0.022, ns; femur neck: r = -0.3136, ns). The adiponectin was the only adipokine which correlated with lumbar spine density in both groups ( r = -0.5081, p < 0.05; -0.2804, p < 0.05), but not with femur density, where this connection disappeared with glucose intolerance ( r = -0.6742, p < 0.01; -0.1723, ns). Relations of bone metabolic markers indicated that bone resorption decreases with worsening of insulin resistance. In conclusion inverse correlations were found between bone density and glucose metabolism, or insulin sensitivity in healthy women in perimenopause, but this connection disappeared with the deterioration of glucose metabolism and progression of insulin resistance measured by the "gold standard" insulin-glucose clamps. Decreasing insulin sensitivity of bones and escape from "metabolic control" may result in frequently observed hyperdensity in Type 2 diabetics.

Presence of PACAP and VIP in embryonic chicken brain.

The aim of the present article was to investigate the occurrence and temporary changes of pituitary adenylate cyclase-activating polypeptide (PACAP)-38 and vasoactive intestinal peptide (VIP) in various brain areas of chicken embryos by means of radioimmunoassay. The highest concentrations of PACAP-38 were measured in the brain stem followed by the hypothalamus, cerebellum, and telencephalon. PACAP-38 levels were significantly higher than those of VIP in all examined brain areas. The levels of both PACAP-38 and VIP showed a tendency to decrease until hatching during embryonic development of the chicken.

Short-term fasting differentially alters PACAP and VIP levels in the brains of rat and chicken.

The present article investigated the levels of pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) in the brains of rats and chickens 12, 36, and 84 h after starvation. PACAP levels increased in both species, 12 h after food deprivation in rats, and with a 24-h delay in chickens. VIP levels showed a more complex pattern: a gradual increase in the hypothalamus and telencephalon, and a significant decrease in the brain stem of rats. In chickens, a decrease was observed in every brain area after 36 h of starvation. These data show that PACAP and VIP are differentially regulated and are involved in the regulatory processes under a food-restricted regimen, and are differentially altered in nocturnal and diurnal species.

Changes in PACAP levels in the central nervous system after ovariectomy and castration.

The aim of the present article was to investigate the influence of gonadectomy on pituitary adenylate cyclase-activating polypeptide (PACAP) levels in different brain areas. In males, there seems to be an inverse relationship between gonadotropins and PACAP in the brain in the acute phase of castration: PACAP levels decreased in almost all brain areas examined within the first week after castration. In females, such pattern was observed in the hypothalamus, brain stem, and temporal cortex. In the pituitary, levels decreased only on the first day after ovariectomy, and later, as in the thalamus, increases were observed. Although the pattern of change showed gender differences, our results provide further evidence that levels of gonadotropins and possibly gonadotropin-releasing hormone influence PACAP levels and that PACAP is involved in the regulation of gonadal functions.

Pituitary adenylate cyclase activating polypeptide plays a role in olfactory memory formation in chicken.

PACAP plays an important role during development of the nervous system and is also involved in memory processing. The aim of the present study was to investigate the function of PACAP in chicken embryonic olfactory memory formation by blocking PACAP at a sensitive period in ovo. Chicken were exposed daily to strawberry scent in ovo from embryonic day 15. Control eggs were treated only with saline, while other eggs received a single injection of the PACAP antagonist PACAP6-38 at day 15. The consumption of scented and unscented water was measured daily after hatching. Animals exposed to strawberry scent in ovo showed no preference. However, chickens exposed to PACAP6-38, showed a clear preference for plain water, similarly to unexposed chicken. Our present study points to PACAP's possible importance in embryonic olfactory memory formation.

Distribution of PACAP-38 in the central nervous system of various species determined by a novel radioimmunoassay.

Pituitary adenylate cyclase activating polypeptide (PACAP) occurs in two molecular forms: PACAP-38 and PACAP-27. Soon after the isolation and chemical characterization of PACAP, the first radioimmunoassay (RIA) methods have been developed, but it is a still rarely used laboratory technique in the field of PACAP research. The aim of the present study was to develop a novel, highly specific PACAP-38 assay to investigate the quantitative distribution of PACAP-38 in the central nervous system of various vertebrate species under the same technical and experimental conditions. Different areas of the brain and the spinal cord were removed from rats, chickens and fishes and the tissue samples were processed for PACAP-38 RIA. Our results indicate that the antiserum used in the RIA is C-terminal specific, without affinity for other members of the vasoactive intestinal polypeptide (VIP)/secretin/glucagon peptide family. The average ID50 value was 48.6+/-3.4 fmol/ml determined in 10 consecutive assays. Detection limit for PACAP-38 proved to be 2 fmol/ml. PACAP-38 immunoreactivity was present in the examined brain areas of each species studied, with highest concentration in the rat diencephalons. High levels of PACAP-38 were also detected in the rat telencephalon, followed by spinal cord and brainstem. The central nervous system of the fish also contained considerable concentrations of PACAP-38, whereas lowest concentrations were measured in the central nervous system of the chicken.

Effects of in ovo treatment with PACAP antagonist on general activity, motor and social behavior of chickens.

Pituitary adenylate cyclase activating polypeptide (PACAP) has been shown to influence nervous system development. The aim of the present study was to investigate the effects of in ovo treatment with the PACAP antagonist PACAP6-38 during embryonic life (E8 and E16) on motor activity and social behavior in chicken. Our results showed that a single injection of PACAP6-38 during the first half of embryonic life caused subtle transient changes in general behavior and motor control when compared to saline-treated controls. Increased activity and reduced anxiety were observed also in a novel environment at 2 days after hatching. However, most of these behavioral differences disappeared by 2 weeks. PACAP6-38-treatment during the first half of embryonic life resulted in markedly reduced social behavior, which was still present at 2 weeks of age. Treatment during the second half of embryonic life resulted in no behavioral differences between control and PACAP6-38-treated chicken. PACAP content in different brain areas was not different between control and PACAP6-38-treated chicken at 5 days or 3 weeks of age, but it decreased significantly with age in both groups. In summary, our results show that PACAP6-38 treatment at E8 caused transient changes in motor behavior, and long-lasting reduction in social behavior.

The effect of PACAP on rhythmic melatonin release of avian pineals.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a ubiquitous member of the VIP/secretin/glucagon bioactive peptide family. The distribution, concentration of PACAP, and its role in the control of rhythmic melatonin (MT) secretion from chicken pineal gland were studied. In the chicken pineal gland (ChPG), 40ng PACAP/g tissue was measured with radioimmunoassay. No midday-midnight differences in the PACAP content of the ChPG could be detected. Immunohistochemical studies of ChPG showed PACAP immunoreactive nerve fibers in the perivascular space and around the pinealocytes. Neither PACAP-labeled perikarya nor PACAP immunopositivity in the pinealocytes could be detected. In five day perifusion experiments, carried out under darkness, both MT and cAMP showed circadian rhythmic release pattern from explanted ChPG. One hour exposure of ChPG to PACAP induced transient (3-4h) elevation of MT and cAMP release. The responses were dose-dependent in the range from 1 to 100nM PACAP concentrations. The magnitude of the response was independent on the phase of the daily cycle in which PACAP was applied. cAMP levels during normal daily cycle and also PACAP-induced cAMP responses always preceded similar changes of MT by about an hour suggesting that cAMP is an intracellular intermediate in controlling MT release from the ChPG. At the same time PACAP, similarly to VIP, did not shift the phase of the in vitro circadian MT rhythm of the pineals. Our data reveal, that PACAP is present in nerve fibers in the chicken pineals and pineal cells contain functioning PACAP-sensitive receptors. PACAP apparently exerts a modulatory effect of the rhythmic MT release from the chicken pineal but does not modify the intrinsic biological clock in the avian pineal gland. Thus, cAMP-mediated intracellular mechanisms in ChPG are not components of the pineal circadian clock, but intermediaries between the clock-mechanism and MT release and may also be components of clock-independent MT release modifiers.

A chronomic tree of life: ontogenetic and phylogenetic 'memories' of primordial cycles--keys to ethics.

A scientific optimization may become possible in ethics to the extent to which any reproducible since cyclic features of spirituality and of criminality become measurable. Should either or both the 'good' or the 'bad' be found to be at least passively influenced by cyclic physical environmental factors, as is putatively the case, these aspects of behavior may eventually become actively manipulable, perhaps utilizable for human survival. Toward this goal, chronomics has already mapped time structures in religious behavior that can lead to a study of underlying geographic/geomagnetic latitude-associated mechanisms. This paper, with further but clearly insufficient data, revealing the hurdle of relative brevity of the available time series constitutes a plea for much longer and denser worldwide time series, for further endeavors in various methods of analyses, some of which are promisingly available.

100 or 30 years after Janeway or Bartter, Healthwatch helps avoid 'flying blind'.

Longitudinal records of blood pressure (BP) and heart rate (HR) around the clock for days, weeks, months, years, and even decades obtained by manual self-measurements (during waking) and/or automatically by ambulatory monitoring reveal, in addition to well-known large within-day variation, also considerable day-to-day variability in most people, whether normotensive or hypertensive. As a first step, the circadian rhythm is considered along with gender differences and changes as a function of age to derive time-specified reference values (chronodesms), while reference values accumulate to also account for the circaseptan variation. Chronodesms serve for the interpretation of single measurements and of circadian and other rhythm parameters. Refined diagnoses can thus be obtained, namely MESOR-hypertension when the chronome-adjusted mean value (MESOR) of BP is above the upper limit of acceptability, excessive pulse pressure (EPP) when the difference in MESOR between the systolic (S) and diastolic (D) BP is too large, CHAT (circadian hyper-amplitude tension) when the circadian BP amplitude is excessive, DHRV (decreased heart rate variability) when the standard deviation (SD) of HR is below the acceptable range, and/or ecphasia when the overall high values recurring each day occur at an odd time (a condition also contributing to the risk associated with 'non-dipping'). A non-parametric approach consisting of a computer comparison of the subject's profile with the time-varying limits of acceptability further serves as a guide to optimize the efficacy of any needed treatment by timing its administration (chronotherapy) and selecting a treatment schedule best suited to normalize abnormal patterns in BP and/or HR. The merit of the proposed chronobiological approach to BP screening, diagnosis and therapy (chronotheranostics) is assessed in the light of outcome studies. Elevated risk associated with abnormal patterns of BP and/or HR variability, even when most if not all measurements lie within the range of acceptable values, becomes amenable to treatment as a critical step toward prevention (prehabilitation) to reduce the need for rehabilitation (the latter often after costly surgical intervention).

Chronoastrobiology: proposal, nine conferences, heliogeomagnetics, transyears, near-weeks, near-decades, phylogenetic and ontogenetic memories.

"Chronoastrobiology: are we at the threshold of a new science? Is there a critical mass for scientific research?" A simple photograph of the planet earth from outer space was one of the greatest contributions of space exploration. It drove home in a glance that human survival depends upon the wobbly dynamics in a thin and fragile skin of water and gas that covers a small globe in a mostly cold and vast universe. This image raised the stakes in understanding our place in that universe, in finding out where we came from and in choosing a path for survival. Since that landmark photograph was taken, new astronomical and biomedical information and growing computer power have been revealing that organic life, including human life, is and has been connected to invisible (non-photic) forces, in that vast universe in some surprising ways. Every cell in our body is bathed in an external and internal environment of fluctuating magnetism. It is becoming clear that the fluctuations are primarily caused by an intimate and systematic interplay between forces within the bowels of the earth--which the great physician and father of magnetism William Gilbert called a 'small magnet'--and the thermonuclear turbulence within the sun, an enormously larger magnet than the earth, acting upon organisms, which are minuscule magnets. It follows and is also increasingly apparent that these external fluctuations in magnetic fields can affect virtually every circuit in the biological machinery to a lesser or greater degree, depending both on the particular biological system and on the particular properties of the magnetic fluctuations. The development of high technology instruments and computer power, already used to visualize the human heart and brain, is furthermore making it obvious that there is a statistically predictable time structure to the fluctuations in the sun's thermonuclear turbulence and thus to its magnetic interactions with the earth's own magnetic field and hence a time structure to the magnetic fields in organisms. Likewise in humans, and in at least those other species that have been studied, computer power has enabled us to discover statistically defined endogenous physiological rhythms and further direct effects that are associated with these invisible geo- and heliomagnetic cycles. Thus, what once might have been dismissed as noise in both magnetic and physiological data does in fact have structure. And we may be at the threshold of understanding the biological and medical meaning and consequences of these patterns and biological-astronomical linkages as well. Structures in time are called chronomes; their mapping in us and around us is called chronomics. The scientific study of chronomes is chronobiology. And the scientific study of all aspects of biology related to the cosmos has been called astrobiology. Hence we may dub the new study of time structures in biology with regard to influences from cosmo- helio- and geomagnetic rhythms chronoastrobiology. It has, of course, been understood for centuries that the movements of the earth in relation to the sun produce seasonal and daily cycles in light energy and that these have had profound effects on the evolution of life. It is now emerging that rhythmic events generated from within the sun itself, as a large turbulent magnet in its own right, can have direct effects upon life on earth. Moreover, comparative studies of diverse species indicate that there have also been ancient evolutionary effects shaping the endogenous chronomic physiological characteristics of life. Thus the rhythms of the sun can affect us not only directly, but also indirectly through the chronomic patterns that solar magnetic rhythms have created within our physiology in the remote past. For example, we can document the direct exogenous effects of given specific solar wind events upon human blood pressure and heart rate. We also have evidence of endogenous internal rhythms in blood pressure and heart rate that are close to but not identical to the period length of rhythms in the solar wind. These were installed genetically by natural selection at some time in the distant geological past. This interpretive model of the data makes the prediction that the internal and external influences on heart rate and blood pressure can reinforce or cancel each other out at different times. A study of extensive clinical and physiological data shows that the interpretive model is robust and that internal and external effects are indeed augmentative at a statistically significant level. Chronoastrobiological studies are contributing to basic science--that is, our understanding is being expanded as we recognize heretofore unelaborated linkages of life to the complex dynamics of the sun, and even to heretofore unelaborated evolutionary phenomena. Once, one might have thought of solar storms as mere transient 'perturbations' to biology, with no lasting importance. Now we are on the brink of understanding that solar turbulences have played a role in shaping endogenous physiological chronomes. There is even documentation for correlations between solar magnetic cycles and psychological swings, eras of belligerence and of certain expressions of sacred or religious feelings. Chronoastrobiology can surely contribute to practical applications as well as to basic science. It can help develop refinements in our ability to live safely in outer space, where for example at the distance of the moon the magnetic influences of the sun will have an effect upon humans unshielded by the earth's native magnetic field. We should be better able to understand these influences as physiological and mechanical challenges, and to improve our estimations of the effects of exposure. Chronoastrobiology moreover holds great promise in broadening our perspectives and powers in medicine and public health right here upon the surface of the earth. Even the potential relevance of chronoastrobiology for practical environmental and agricultural challenges cannot be ruled out at this early stage in our understanding of the apparently ubiquitous effects of magnetism and hence perhaps of solar magnetism on life. The evidence already mentioned that fluctuations in solar magnetism can influence gross clinical phenomena such as rates of strokes and heart attacks, and related cardiovascular variables such as blood pressure and heart rate, should illustrate the point that the door is open to broad studies of clinical implications. The medical value of better understanding magnetic fluctuations as sources of variability in human physiology falls into several categories: 1) The design of improved analytical and experimental controls in medical research. Epidemiological analyses require that the multiple sources causing variability in physiological functions and clinical phenomena be identified and understood as thoroughly as possible, in order to estimate systematic alterations of any one variable. 2) Preventive medicine and the individual patients'care. There are no flat 'baselines', only reference chronomes. Magnetic fluctuations can be shown statistically to exacerbate health problems in some cases. The next step should be to determine whether vulnerable individuals can be identified by individual monitoring. Such vulnerable patients may then discover that they have the option to avoid circumstances associated with anxiety during solar storms, and/or pay special attention to their medication or other treatments. Prehabilitation by self-help can hopefully complement and eventually replace much costly rehabilitation. 3) Basic understanding of human physiological mechanisms. The chronomic organization of physiology implies a much more subtle dynamic integration of functions than is generally appreciated. All three categories of medical value in turn pertain to the challenges for space science of exploring and colonizing the solar system. The earth's native magnetic field acts like an enormous umbrella that offers considerable protection on the surface from harsh solar winds of charged particles and magnetic fluxes. The umbrella becomes weaker with distance from the earth and will offer little protection for humans, other animals, and plants in colonies on the surface of the moon or beyond. Thus it is important before more distant colonization is planned or implemented to better understand those magnetism-related biological- solar interactions that now can be studied conveniently on earth. (ABSTRACT TRUNCATED)

Comparative distribution of VIP in the central nervous system of various species measured by a new radioimmunoassay.

Vasoactive intestinal polypeptide (VIP) occurs in high concentrations throughout the gut and the nervous system. The presence of VIP has been shown in a number of species, mainly by immunohistochemistry. The aim of the present study was to develop a new, highly specific VIP radioimmunoassay to investigate the distribution of VIP in the central nervous system of various vertebrate and invertebrate species. Different areas of the brain and spinal cord were removed from rats, chickens, turtles, frogs and fishes. The cerebral ganglia and the ventral ganglionic chain were investigated in the earthworm. The tissue samples were processed for VIP radioimmunoassay. Our results show that the antiserum used in the radioimmunoassay turned to be C-terminal specific, without significant affinity to other members of the VIP peptide family. Detection limit of the assay was 0.1 fmol/ml. Highest concentrations were found in the turtle diencephalon, followed by other brain areas in the turtle and rat. All other brain areas in the examined species contained significant levels of VIP. Immunoreactivity was also shown in the cerebral and ventral ganglia of the earthworm. In summary, our results show comparative quantitative distribution in representative species of the phylogenetic line, using the same experimental conditions.

Influence of pinealectomy on levels of PACAP and cAMP in the chicken brain.

One of the recently found functions of pituitary adenylate cyclase activating polypeptide (PACAP) is the modulation of circadian rhythms. Widespread distribution of PACAP-containing neurons and receptors has been shown in the chicken. Recently, we have demonstrated that PACAP levels oscillate in a circadian manner in the chicken brain. Daily variation in PACAP levels might be influenced by several regulatory mechanisms. Among the structures that may regulate PACAP levels, one candidate is the pineal gland. Therefore, in the present study, we investigated the effect of pinealectomy on the levels of PACAP in the chicken brain. Animals were kept under 12:12-h light-dark schedule. Pinealectomy was performed at 3 weeks of age; sham-operated animals were used as controls. The animals were sacrificed at 15 and 24 h 1 week after pinealectomy. The brainstem and diencephalon were removed, and tissue samples were processed for PACAP and cAMP radioimmunoassay (RIA).PACAP and cAMP levels showed nighttime elevations in both the sham-operated and pinealectomized animals, except for the PACAP content in the diencephalon of pinealectomized chicken. PACAP levels of pinealectomized animals were significantly higher in the diencephalon and brainstem as compared to the control animals at both time-points. Levels of cAMP correlated well with levels of PACAP. The present results provide evidence that the pineal gland has an inhibitory impact on PACAP-neurons in the chicken brainstem and diencephalon.