Improving diet, activity and wellness in adults at risk of diabetes: randomized controlled trial.

OBJECTIVE: The purpose of this analysis is to examine the effect of an algorithm-driven online diabetes prevention program on changes in eating habits, physical activity and wellness/productivity factors. METHODS: The intervention, Alive-PD, used small-step individually tailored goal setting and other features to promote changes in diet and physical activity. A 6-month randomized controlled trial was conducted among patients from a healthcare delivery system who had confirmed prediabetes (n =339). Change in weight and glycemic markers were measured in the clinic. Changes in physical activity, diet and wellness/productivity factors were self-reported. Mean age was 55 (s.d. 8.9) years, mean body mass index was 31 (s.d. 4.4) kg m(-2), 68% were white and 69% were male. RESULTS: The intervention group increased fruit/vegetable consumption by 3.71 (95% confidence interval (CI) 2.73, 4.70) times per week (effect size 0.62), and decreased refined carbohydrates by 3.77 (95% CI 3.10, 4.44) times per week both significantly (P<0.001) greater changes than in the control group. The intervention group also reported a significantly greater increase in physical activity than in the control group, effect size 0.49, P<0.001. In addition, the intervention group reported a significant increase in self-rated health, in confidence in ability to make dietary changes and in ability to accomplish tasks, and a decrease in fatigue, compared with the control group. These changes paralleled the significant treatment effects on glycemic markers and weight. CONCLUSIONS: In addition to promoting improvements in weight and glycemic markers, the Alive-PD program appears to improve eating habits and physical activity, behaviors important not just for diabetes prevention but for those with diagnosed diabetes or obesity. The improvements in wellness/productivity may derive from the diet and activity improvements, and from the satisfaction and self-efficacy of achieving goals.

Expression of acetylcholine receptor isoforms at extraocular muscle endplates.

PURPOSE: To determine the expression of fetal and adult acetylcholine receptor (AChR) isoforms among extraocular muscle (EOM) en plaque and en grappe endplates. METHODS: Antibodies against peptide fragments of the gamma- and epsilon-subunits of the fetal and adult AChRs and alpha-bungarotoxin were used in immunofluorescence experiments to stain rat neonatal leg, adult diaphragm, and extraocular rectus muscle endplates. RESULTS: Anti-epsilon antibodies intensely stained diaphragm endplates weakly stained rare neonatal endplates. Anti-gamma antibodies stained neonatal, but not diaphragm, endplates. Anti-epsilon antibodies bound to all en plaque and en grappe endplates of extraocular muscle. Anti-gamma antibodies bound to global and orbital en grappe endplates. All en plaque endplates of the orbital region and a subset of endplates in the global region stained with anti-gamma antibodies. CONCLUSIONS: All en grappe endplates and certain en plaque endplates of EOM are the only mature endplates that coexpress the adult and fetal AChR isoforms. The expression of both isoforms may be important to determine contractile properties, protein expression regulation, and EOM susceptibility to myasthenia gravis.

Plasma angiotensin(1-7) immunoreactivity is increased by salt load, water deprivation, and hemorrhage.

In this study we investigated the effects of dehydration and hemorrhage on circulating levels of the heptapeptide, angiotensin(1-7). In water-deprived rats, a twofold increase in plasma angiotensin(1-7) was associated with similar increases in plasma renin activity, and angiotensin I and angiotensin II levels. In salt-loaded rats, plasma angiotensin(1-7) levels increased fourfold; however, other components of the renin-angiotensin system were suppressed or unchanged. In salt-loaded rats, increases in plasma angiotensin II levels in response to hemorrhage in normal rats were severely blunted, whereas angiotensin(1-7) plasma levels increased proportionately to the loss of blood volume. These results suggest that angiotensin(1-7) plasma concentration can be selectively regulated during dehydration and hemorrhage.

Cardiovascular changes during focal cerebral ischemia in rats.

BACKGROUND AND PURPOSE: Recent studies have suggested that cerebral infarction influences autonomic activity and may contribute to sudden death. The goal of this study was to examine effects of focal cerebral infarction on mean arterial pressure and heart rate. METHODS: Halothane-anesthetized rats were assigned to two groups: stroke (n = 10), in which the middle cerebral artery or an adjacent vessel was embolized with a silicone cylinder, and sham (n = 8), in which rats were sham embolized (saline). Arterial pressure and heart rate were measured for 90 minutes and again 24 hours after vascular occlusion. A change in electroencephalographic amplitude of -45% after embolization was used to determine if a significant degree of infarction was present. RESULTS: Vascular occlusion produced a significant increase in mean arterial pressure at 10, 60, and 90 minutes (p < 0.05). Changes in heart rate were significantly greater (p < 0.05) than in sham-treated rats at 10 and 30 minutes after embolization. In contrast, mean arterial pressure and heart rate measured 24 hours after embolization were similar in both groups. Anatomic analysis of the infarcted areas demonstrated that either insular cortex or amygdala was affected in all embolized rats. CONCLUSIONS: This study indicates that cerebral infarction produces a transient elevation of mean arterial pressure and heart rate. However, within 24 hours both parameters returned to preinfarcted levels. Our findings are consistent with clinical reports that indicate that mean arterial pressure and heart rate of stroke patients are similar to those of other groups when they are admitted to the hospital, although other cardiovascular parameters are greatly altered.

Relationship of vasopressin with NADPH-diaphorase in the hypothalamo-neurohypophysial system.

The relative anatomical distributions of vasopressin and the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) were examined in the hypothalamo-neurohypophysial system using immunocytochemical and histochemical techniques. Double-labeled neurons were localized predominately to rostral aspects of the hypothalamo-neurohypophysial system. Only scattered double-labeled cells were found throughout the subdivisions of the supraoptic and paraventricular nuclei. Because previous investigations suggest that nitric oxide may play a critical role in neurotransmission and reductions in NADPH-d have been reported in the neural lobe of salt-loaded animals, the present report of its coexistence with the antidiuretic hormone vasopressin in the hypothalamo-neurohypophysial system further supports a role for these neuroactive substances in mechanisms modulating fluid homeostasis.

Angiotensin-(1-7) and nitric oxide synthase in the hypothalamo-neurohypophysial system.

The organization of angiotensin (Ang)-(1-7) immunoreactivity with respect to neurons containing the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), in the hypothalamo-neurohypophysial (HNS) system was examined. The majority of neurons in this system were single labeled with Ang-(1-7) or NADPH-d and were found localized in two separate populations of neurons within the HNS. A small number of double-labeled neurons were observed in the supraoptic (SO) and paraventricular (PV) nuclei. Double-labeled accessory neurosecretory neurons were also found distributed between the SO and PV. Although a well-defined function for nitric oxide in the magnocellular hypothalamic system has not been determined, the codistribution and limited coexistence of Ang-(1-7), a heptapeptide involved in antidiuresis, and NADPH-d in the HNS suggests a potential role for these substances in mechanisms modulating fluid homeostasis.

Tissue renin-angiotensin systems in renal hypertension.

Angiotensinogen messenger RNA (mRNA) levels were measured in the brain (hypothalamus, lower brain stem, cerebellum), liver, kidneys, and adrenal glands of rats made hypertensive by ligation of the aorta between the renal arteries. We also measured renin mRNA in the kidneys of these renal hypertensive rats. The early phase of hypertension (day 6) was associated with significant increases in plasma renin activity and levels of circulating angiotensin II. The circulating renin-angiotensin system was not activated in the later phase of hypertension (day 24). Angiotensinogen mRNA levels were elevated in the lower brain stem of hypertensive rats at both stages of hypertension. In contrast, angiotensinogen mRNA levels in the hypothalamus were increased only at day 6 after aortic ligation. Decreased levels of angiotensinogen mRNA were observed in the cerebellum in both the early and later phases of the hypertension. Angiotensinogen mRNA levels in the adrenal gland below the ligature fell in the early phases but rose in the later phases of hypertension. Renin mRNA levels of the ischemic kidney remained elevated at both the early and later phases, whereas in both ischemic and nonischemic kidneys, levels of angiotensinogen mRNA remained below sham values throughout the period of study. These results indicate differential expression of renin-angiotensin system mRNAs in tissues of renal hypertensive rats. The differential changes in the expression of angiotensinogen mRNA over the course of development and maintenance of renal hypertension suggest that factors in addition to angiotensin II are important in modulating the expression of renin-angiotensin system genes.

Attenuated vascular reactivity in dogs with anteroventral third ventricle lesions.

Lesion of the anteroventral portion of the third cerebral ventricle causes hypernatremia, adipsia, and attenuation of the pressor response to intravenous administration of angiotensin II and norepinephrine. In addition, these lesions prevent the development of several experimental models of hypertension. In this study, a lesion of the third cerebral ventricle region was made in 14 dogs. In seven dogs in which hypernatremia developed the lesions included the organum vasculosum of the lamina terminalis; seven animals in which the circumventricular organ was spared by the lesion remained normonatremic. Vascular responsiveness of isolated right carotid artery rings to angiotensin II and phenylephrine was assessed 3 days after lesioning the anteroventral portion of the third cerebral ventricle. In endothelium-denuded ring vessels, vasoconstrictor responses to phenylephrine were significantly decreased in animals both with and without inclusion of the organum vasculosum of the lamina terminalis. A similar effect was observed in intact vessels of dogs in which the circumventricular organ was spared but not in those with lesions that included this area. In contrast, angiotensin II-induced vasoconstriction was significantly decreased in the arteries with intact endothelium of both groups of lesioned animals. These data show that lesion of the anteroventral third ventricle area alters alpha 1-adrenergic and angiotensin II vascular responsiveness in isolated carotid artery rings with the possible participation of the endothelium.

The cytoarchitectural organization of the human parabrachial nuclear complex.

The cytoarchitecture of the parabrachial nuclear complex in adult and infant human brain was studied. Lying in the dorsolateral pontine tegmentum, surrounding the superior cerebellar peduncle, this complex in several mammalian species is interconnected with autonomic centers in the medulla oblongata, hypothalamus, thalamus, amygdala, and cortex. Postmortem human brain tissue was stained for Nissl substance and fiber tracts with a modified Klüver-Barrera stain. Examination of the tissue revealed distinct medial and lateral subdivisions, similar to descriptions in other mammals. The organization of the parabrachial complex was more obvious in the infant tissue than the adult, because of less myelination of the large fibers of the adjacent superior cerebellar peduncle and lateral lemniscus. Within the lateral parabrachial nucleus, 7 distinct subgroups of cells were identified on the basis of their location and staining characteristics. These were named according to their location in the parabrachial complex and were the central, superior, interstitial, dorsal, dorsolateral, lateral, and ventrolateral. Two subnuclei were found within the medial parabrachial nucleus, the dorsomedial and ventromedial. Additionally, neurons within the superior cerebellar peduncle were arranged in cellular bridges running between the lateral and medial subdivisions. These data suggest that the parabrachial complex in the human brain is organized cytoarchitecturally, similar to other mammals, however, this organization is obscured with increasing myelination in adulthood.

Pathways of angiotensin formation and function in the brain.

New findings from this laboratory suggest that fragments of angiotensin derived from the amino (N-)terminus are biologically active end products of the renin-angiotensin system. In vitro and in vivo experiments revealed that the heptapeptide angiotensin-(1-7) [Ang-(1-7)] is a major endogenous product of the renin-angiotensin system cascade in the brains of rats and dogs. Additional studies with enzyme inhibitors showed that Ang-(1-7) is produced directly from angiotensin I by an enzyme other than the angiotensin converting enzyme. Immunocytochemical fibers within the hypothalamo-neurohypophyseal vasopressinergic system of the rat. Although Ang-(1-7) is as potent as angiotensin II (Ang II) in stimulating release of vasopressin from superperfused hypothalamo-neurohypophyseal explants, the heptapeptide has no dipsogenic or vasoconstrictor activity. In contrast, Ang-(1-7) mimics the effects of Ang II in augmenting the intrinsic discharge rate of neurons within the vagal-solitary complex and in causing monophasic depressor responses after microinjection into the medial region of the nucleus tractus solitarii. The evidence obtained in these experiments suggests novel mechanisms for the generation of angiotensin peptides in the brain. Additionally, the findings suggest that some of the biological actions ascribed to Ang II might be conveyed by the endogenous production of other angiotensin peptides that are generated by enzymatic pathways alternate to those described in the peripheral circulation.

The canine nucleus tractus solitarii: light microscopic analysis of subnuclear divisions.

The nucleus tractus solitarii (nTS) is a complex structure situated in the dorsal medulla oblongata. This region receives primary visceral and gustatory sensory afferent fibers and has widespread interconnections with brainstem structures, hypothalamus, and limbic forebrain. In both rat and cat distinct subnuclei correlate with specific functions of the nTS. Since the canine model is used extensively for physiological study and evidence from this laboratory supports a critical role for the canine nTS in cardiovascular function, we examined its morphological organization. Light microscopic analysis of cellular and fiber patterns of the nTS revealed nine discrete regions based on cytoarchitecture: the commissural, lateral, ventral, dorsal, intermediate, interstitial and medial subnuclei, the subnucleus gelatinosa, and the dorsal parasolitary region. Analysis of each subnucleus revealed that both the lateral and ventral subnuclei contained two distinct neuronal groups based on cell size. Neurochemical and functional correlates are being provided by ongoing analyses of each subnucleus of the nTS.

Peptide-containing pathways from the parabrachial complex to the central nucleus of the amygdala.

The present investigation was undertaken to examine the organization of peptidergic projections that exist between the parabrachial nuclear complex (PB) and the central nucleus of the amygdala (CNA). The retrograde tracer True Blue was injected into the CNA of adult rats. The brain tissue was then reacted immunocytochemically to localize neurotensin (NT), substance P (SP), methionine enkephalin (ENK), vasoactive intestinal polypeptide (VIP), somatostatin (SS), and cholecystokinin octapeptide (CCK). Following microinjection of True Blue in the CNA, retrogradely-labeled neurons were located primarily in the external lateral subnucleus, abutting the brachium conjunctivum. In animals that received colchicine pretreatment, two populations of neurons, containing either SP or NT, were found to project to the CNA. In addition, cells containing CCK, ENK, VIP, or SS were not found to be a part of this projection system. These data suggest that neurons in the PB project to the CNA and are, in part peptide-containing.

Immunocytochemical localization of angiotensin-(1-7) in the rat forebrain.

Recent findings by this group have led us to reconsider the view that amino (N-) terminal fragments of angiotensin (Ang) II are inactive degradation products of renin-angiotensin system. To further examine this possibility, an antibody to Ang-(1-7), the N-terminal heptapeptide, was produced to demonstrate the neuroanatomical distribution of the rat brain. Ang-(1-7)-immunoreactivity was found in paraventricular, supraoptic, and suprachiasmatic nuclei, bed nucleus of the stria terminalis, substantia innominata, median eminence, and neurohypophysis. This distribution of Ang-(1-7) in the rat forebrain, together with our previous demonstrations of vasopressin secretion in response to this peptide, suggest that Ang-(1-7) functions as a neuromodulator.

Distribution of catecholaminergic neuronal systems in the canine medulla oblongata and pons.

The distribution of catecholamine-containing neurons, fibers, and varicosities in the brainstem of both adult and juvenile dogs was mapped in detail with glyoxylic acid histofluorescence. Four separate groups of catecholamine-fluorescent neurons were identified within the canine medulla and pons in locations comparable to the A1, A2, A5, and A6 regions reported in other species. However, aspects of the pattern and density of the catecholaminergic neuronal systems appeared to be unique to the dog. The A1 neurons of the caudal ventrolateral medulla were much more scattered than in rats or rabbits, but relatively similar to cats. In the A2 region of the dorsomedial medulla, catecholaminergic cells and fibers were uniquely distributed compared to other species: fluorescent neurons were scattered only within the dorsal motor nucleus of the vagus, and a distinctive pattern of fibers and varicosities outlined the nucleus of the solitary tract and dorsal motor nucleus of the vagus. The A5 neurons of the rostral ventrolateral medulla appeared at the rostral limit of the A1 region. Fluorescent A5 cells were more sparse than in rats or primates, and were patterned similarly to cats and rabbits. The canine A6 region contained the most extensive and dense grouping of catecholamine neurons and was similar in pattern to the rabbits but less extensive than that seen in cats or primates. An ascending catecholaminergic fiber pathway was traced through the central tegmental field of the canine medulla and pons, with features similar to the primate. The present study provides the first description of the catecholaminergic neuronal systems of the canine medulla.

A hypothesis regarding the function of angiotensin peptides in the brain.

Studies of the in vivo and in vitro metabolism of angiotensin peptide precursors, and of angiotensin II (Ang II) in tissues, has revealed the possibility that some of the fragments formed through specific enzymatic pathways are bioactive. There is evidence that Ang III is as potent as Ang II in stimulating thirst and causing aldosterone secretion. New findings from this laboratory have led us to reevaluate the concept that fragments of angiotensins derived from the amino (N-) terminus are devoid of biological activity. Using in vitro and in vivo techniques, we showed that Ang-(1-7) is processed from Ang I in amounts equal to or greater than Ang II. In addition, Ang-(1-7) generation is not dependent upon Ang I converting enzyme (ACE) activity in homogenates of canine brain stem. This heptapeptide promotes release of vasopressin from perifused hypothalamo-neurohypophysial explant and stimulates neural responses when microinjected into the vagal-solitary complex. The data supporting these findings are discussed below.

Role of area postrema pressor mechanisms in the regulation of arterial pressure.

This article discusses the data which established that angiotensin II modulates the tonic and reflex control of cardiovascular function by actions on the nuclear regions of the dorsal medulla oblongata. Although physiological evidence for the modulatory actions of angiotensin II in structures of the lower brainstem has been gathered over the past 16 years, only the recent application of new neurobiological techniques has allowed a more definitive understanding of its role. The identification of high affinity angiotensin II binding sites within the parenchyma of the area postrema with the technique of in vitro receptor autoradiography has provided anatomical validity for a role of angiotensin II in the central nervous system. The added discovery of angiotensin II binding sites in subnuclear components of the nucleus tractus solitarii and the motor nucleus of the tenth cranial nerve provides additional information on the various mechanisms through which angiotensin II may affect the intrinsic activity of the brainstem neuronal circuits involved in the integration of baroreceptor and sensory visceromotor function.

Neuropeptide and monoamine components of the parabrachial pontine complex.

The present investigation examined the distributions of immunoreactive neurotensin (NT), cholecystokinin octapeptide (CCK), substance P (SP), methionine enkephalin (ENK), vasoactive intestinal polypeptide (VIP), somatostatin (SS), rat neurophysin II (RNP II), vasopressin (VP), oxytocin (OXY), tyrosine hydroxylase (TH), and serotonin in the parabrachial nuclear complex (PB) of the rat. All of these substances were localized to the PB and they appeared to be chemoarchitecturally organized within the complex. The lateral subdivision (PBL) was organized medial-lateral and ventral-dorsal. Specifically NT, CCK, and SP immunoreactive fibers were found to be the most dense in the ventral aspect of the PBL. The distribution of NT-containing fibers was similar to the pattern of CCK-containing fibers and these were localized primarily to the central zone of the PBL. Immunoreactive SP fibers and cells were found in the external and internal zones ventrally and surrounding the dorsal and dorsolateral nuclei in the PBL. Somatostatin, ENK and VIP were found to be the most dense in the dorsal PBL. Serotonin- and TH-containing cells and fibers were found in both the PBL and PBM. These results, coupled with the observations of neuronal connections of the PB and the known functions of this region, underscore the potential involvement for these neuropeptides and monoamines in limbic-brainstem mechanisms of autonomic control.

The distribution of substance P in the canine dorsomedial medulla.

To define the neurochemical substrates underlying cardiovascular regulatory mechanisms in the canine dorsal medulla, we characterized immunocytochemically the organization of substance P (SP) in the dorsomedial medulla. Substance P immunoreactivity was the most dense in the dorsal nucleus tractus solitarii (nTS). Varicose fibers and cells containing this neuropeptide were localized in the dorsal motor nucleus of the vagus (dmnX) and nucleus commissuralis. A few scattered fibers were observed within the area postrema. The distribution of this peptide suggests a topographical organization within the dorsomedial medulla of the dog that is closely related to the cytoarchitectural organization. In addition, the patterns of SP immunoreactivity overlap the distribution of vagal afferent fibers. These observations are discussed in relation to the possible function of SP in the dorsomedial medulla.

Correlation between angiotensin II binding sites and substance P in the canine brain stem.

Specific angiotensin II (ANG II) binding sites in the dorsal aspects of the medulla oblongata of dogs and rats were shown previously to be dependent upon intact sensory and motor components of the vagus nerve. The present studies compared the distribution of ANG II binding sites in the canine medulla with the visualization of substance P immunoreactive fibres, since this peptide is known to be present in vagal afferent fibres. Dense bands of substance P-containing fibres were found to cap the tractus solitarius (TS) in the dorsal subdivision of the nucleus tractus solitarii (nTS) at a level corresponding to the region of highest ANG II binding. In addition, moderate densities of both substance P immunoreactivity and ANG II binding sites were dually localized in the medial nTS and the ventral portion of the dorsal motor nucleus of the vagus (dmnX). Since previous studies indicated that ANG II binding sites are associated with vagal afferent fibres in the nTS and efferent motor neurons in the dmnX, their apparent association with substance P immunoreactive fibres suggests that a functional interaction may occur between these two peptides in the central integration of cardiovascular function.