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A Seltzer

Publications and source records attributed to A Seltzer.

At least 19 recordsLinked to original sources
PubMed2001

Autoradiographic localization of angiotensin II receptors in developing rat cerebellum and brainstem.

The role of Angiotensin II (Ang II) as a growth promoting or modulating factor has recently become a field of intensive research. A central issue in developmental neurobiology is the understanding of mechanisms governing the formation of spatially ordered connections. In this study, we show the localization of Ang II receptor subtypes by autoradiography in 2-week-old rat hindbrains confronting these data with membrane binding assays. Competition studies done on membrane preparations evidence no major changes on the relative affinities for both receptor subtypes between 2-week-old and adult rat tissues. By autoradiography, we found that all the areas (1-10) of the 2-week-old cerebellum showed both receptor subtypes present in complementary adjacent layers. Areas expressing a high level of AT2 receptors follow: inferior colicullus (IC), dorso tegmental nucleus, central (DTgC), subcoeruleus, alpha, sensory root of the trigeminal nerve, principal sensory root trigeminal nucleus (Pr5, Pr5VL) supragenual nucleus, genu facial nerve, facial nucleus, cerebellar peduncles, vestibular and lateral nuclei. Spinal trigeminal, (oral) and Raphe nuclei express AT1 receptor subtype. The high level of Ang II AT2 receptors present in the cerebellar peduncles might have a meaning on the establishment of the olivo-cerebellar connection. The high expression of Ang II AT2 receptors on 2-week-old rat hindbrains, a critical age on development, as well as its disappearance in the adult, strongly suggests a probable role of these receptors in cell migration and neuronal synaptogenesis.

Animals↗
PubMed1994

Heterogeneous expression of angiotensin II AT1 receptors in neointima of rat carotid artery and aorta after balloon catheter injury.

We examined the expression of angiotensin II receptor subtypes and angiotensin-converting enzyme in the rat aorta and carotid artery at 1, 2, 4, 8, 15, and 30 days after balloon catheter injury or sham surgery. The AT1 receptor expression was enhanced in the neointima at 8 days in the aorta and carotid artery compared to that in intact media. Maintenance of the high expression of AT1 receptors in the neonintimal tissue at 15 and 30 days was localized to a subpopulation of neointimal cell close to the lumen of the vessel and was correlated to the distribution of smooth muscle cells immunoreactive to proliferating cell nuclear antigen. During the initial stages after injury, binding of [125I]351A to angiotensin-converting enzyme was significantly decreased in both the intima/media layers as well as adventitia in carotid artery and aorta. Binding of [125I] 351A to angiotensin-converting enzyme was significantly lower in the neointima compared to that in the intima/media of intact vessels. Our results reveal that the expression of AT1 receptors is heterogeneous in the neointima, and suggest that enhanced expression of AT1 receptors in the balloon catheter-injured carotid artery and aorta may be limited to proliferating intimal smooth muscle cells.

Angioplasty, Balloon↗
PubMed1994

Multiple personality: a psychiatric misadventure.

Though multiple personality disorder has been diagnosed with increasing frequency over the past decade, its validity has been called into question. A brief review of the literature indicates a likelihood of socio-cultural influences and iatrogenicity in many if not most cases. Symptoms of multiple personality disorder parallel other psychiatric syndromes but are usually given diagnostic priority. The author has described five cases diagnosed multiple personality disorder by another health professional in which iatrogenic influences are clearly evident. All renounced both the diagnosis and the alleged sex abuse etiology. The patients possess insight into the role their attachment and dependency on their former therapist played in the development of their apparent multiple personality disorder.

Adult↗
PubMed1993

Angiotensin II receptor subtypes and angiotensin-converting enzyme in the fetal rat brain.

Angiotensin II (ANG II) receptor subtypes (AT1, displaced by losartan, and AT2, displaced by CGP 42112A) were characterized by quantitative autoradiography after incubation with the ANG II agonist [125I]Sar1-ANG II, in specific brain nuclei of 19-day-old rat embryos. Binding to AT1 receptors, located in the subfornical organ, paraventricular nucleus, nucleus of the solitary tract and choroid plexus, was sensitive to incubation with GTP gamma S. The sensitivity of AT2 receptors to GTP gamma S was heterogeneous. In the ventral thalamic, rostral hypoglossal and medial geniculate nuclei, and in the locus coeruleus, binding to AT2 receptors was sensitive to GTP gamma S and these areas belong to the AT2A subgroup. Conversely, in the inferior olive, medial (fastigial) cerebellar nucleus and caudal part of the hypoglossal nucleus, areas belonging to the AT2B subgroup, binding was insensitive to GTP gamma S. AT2 receptors were also present in cerebral arteries. In the fetal anterior pituitary, AT1 receptors predominated. The angiotensin-converting enzyme (ACE; EC 3.4.15.1) was studied by autoradiography with the selective inhibitor [125I]351A. In 19-day-old embryos, ACE was highly expressed in choroid plexus, with high concentrations in subfornical organ, posterior pituitary and cerebral arteries. No ACE binding was detected in extrapyramidal structures or anterior pituitary in 19-day-old embryos.

Angiotensin II↗
PubMed1993

Effects of deoxycorticosterone acetate (DOCA) and aldosterone on Sar1-angiotensin II binding and angiotensin-converting enzyme binding sites in brain.

1. It is known that regulation of salt appetite is a complex behavior controlled in the brain by interaction of mineralocorticoids (MC) and angiotensin II (ANGII). To investigate the effects of MC on ANGII receptors and ANGII synthesis, we have studied two models of salt appetite control. 2. In the first model, doses of DOCA sufficient to induce salt appetite of intact rats were given. In the second one, we studied the effects of aldosterone (ALDO) in doses sufficient to suppress salt appetite developed by prior adrenalectomy (ADX). 3. Binding to ANGII receptors was determined in brain sections incubated with 3 nM [125I]Sar1 ANGII, exposed to [3H]Hyperfilm with an optical density of autoradiograms measured by computerized densitometry. Sar1-ANGII binding was increased by DOCA treatment in the median preoptic nucleus (MnPO) and subfornical organ (SFO) but not in the paraventricular nucleus (PVN) in comparison to vehicle-treated rats. ALDO treatment was without effect on the MnPO but increased ANGII binding in the SFO and PVN. Neither hormone affected binding in the median eminence or anterior pituitary (AP). 4. In contrast to effects on Sar1-ANGII binding in selected areas, [125I]351A binding to angiotensin-converting enzyme (ACE) was unchanged by DOCA or ALDO administration in the SFO, caudate putamen, AP, or posterior pituitary. 5. These findings suggest that MC modulation of the renin-angiotensin system is exerted at the central, and not at the pituitary level. ANGII receptors were modulated in a dose- and region-specific manner: while DOCA may promote their actions upon the MnPO and SFO, ALDO actions may occur at the PVN and SFO. This mechanism may not require increased generation of ANGII in the brain or pituitary.

Adrenalectomy↗
PubMed1993

Characterization of brain angiotensin II AT2 receptor subtype using [125I] CGP 42112A.

Recently two subtypes of angiotensin receptors have been described, AT1 and AT2. Currently used radiolabeled agonists and antagonists are not able to discriminate between these receptors subtypes. Here we characterize the use of [125I] CGP 42112A, a novel, specific ligand for AT2 receptors, in a membrane binding assay and in autoradiography of brain sections of 2 week old rats. [125I] CGP 42112A bound with high affinity and autoradiography revealed binding selectively localized to areas known to express the AT2 receptor subtype only. CGP 42112A, angiotensin II, angiotensin III and PD 123177 competed for [125I] CGP 42112A binding, with potencies consistent with high affinity and specific binding to AT2 receptors. Thus [125I] CGP 42112A will be a useful new tool to study AT2 receptors.

Angiotensin II↗
PubMed1993

Up-regulation of pituitary [125I]insulin-like growth factor-I (IGF-I) binding and IGF binding protein-2 and IGF-I gene expression by estrogen.

To evaluate the effects of estrogen on the rat pituitary insulin-like growth factor (IGF) system, binding of [125I]IGF-I and in situ hybridization for IGF-I, the IGF-I receptor and IGF binding protein-2 (IGFBP-2) were coupled with quantitative autoradiography. The groups included intact cycling females, intact males, and gonadectomized males and females with or without estrogen pellet implants. Binding of [125I]IGF-I in the anterior lobe of the pituitary occurred in dense clusters over a diffuse lower density background. [125I]IGF-I binding was significantly increased in the estrogen-treated groups and was highest at proestrus compared to the rest of the estrous cycle. IGF-I receptor messenger RNA (mRNA) was distributed diffusely through the anterior pituitary and was not different between the respective gonadectomized and estrogen-treated groups. IGFBP-2 mRNA was clustered throughout the anterior pituitary and was significantly higher in the estrogen-treated groups as noted above for [125I]IGF-I binding. IGF-I mRNA was diffuse throughout the anterior pituitary and was also significantly higher in the estrogen-treated groups. In the neural lobe, [125I]IGF-I binding, IGFBP-2 mRNA, IGF-I receptor mRNA, and IGF-I mRNA were all uniformly distributed and did not differ between groups. The results show that circulating estrogen differentially regulates components of the pituitary IGF-I system in a region-specific manner and suggest that a portion of IGF binding in the anterior pituitary may be to IGFBP-2.

Animals↗
PubMed1993

Reproductive hormones modulate angiotensin II AT1 receptors in the dorsomedial arcuate nucleus of the female rat.

Angiotensin II AT1 receptors are highly localized in the dorsomedial arcuate nucleus. AT1 receptor number is very low during proestrus and in ovariectomized and male rats, and is high only during the estrus phase of the estrous cycle and after ovariectomized rats receive a sequential estrogen-progesterone treatment. Our results suggest that the mechanism of the estrogen-progesterone inhibition of the prolactin surge may involve the selective stimulation of dorsomedial arcuate AT1 receptors.

Animals↗
PubMed1992

Enhanced angiotensin converting enzyme binding in arteries from spontaneously hypertensive rats.

AIM: To localize and measure angiotensin converting enzyme (ACE) in different vascular beds of genetically hypertensive rats. METHODS: Quantitative autoradiography using the angiotensin converting enzyme (E.C. 3.4.15.1) inhibitor [125I]351A. RESULTS: [125I]351A binding was significantly increased in the ascending aorta (both adventitia and intima), descending (abdominal) aorta, carotid artery and coronary arteries of adult, 12-week-old spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto (WKY) rats. Increased [125I]351A binding was also present in the descending aorta of 1-week-old SHR compared with age-matched WKY rats, and both groups of young rats had much higher binding than adult rats. No difference in [125I]351A binding was found in the caudal (tail) artery of adult SHR compared with WKY rats. In both the atria and the ventricles of adult SHR, [125I]351A binding was very significantly reduced. CONCLUSIONS: Our results indicate that higher ACE concentrations occur in some arteries of genetically hypertensive rats, and support the hypothesis that local arterial concentrations of ACE affect the development and maintenance of genetic hypertension.

Animals↗
PubMed1992

Estrogens regulate angiotensin-converting enzyme and angiotensin receptors in female rat anterior pituitary.

We studied the effects of the estrous cycle, ovariectomy and estrogen replacement on angiotensin-converting enzyme (ACE) (kininase II, EC 3.4.15.1) and angiotensin II (AT) receptors in the pituitary gland of the female rat. Quantitative autoradiography, with the use of consecutive pituitary sections, allowed for simultaneous determination of changes in binding and in the potential AT synthetic ability of individual pituitaries, and for a correlation between these two phenomena. In the anterior pituitary, ACE activity and binding of the ACE inhibitor [125I]-351A were not changed during the estrous cycle. Ovariectomy produced a significant increase in ACE activity and binding, and both of these parameters returned to normal after estrogen replacement. There were no changes in ACE activity or binding in the posterior pituitary during the estrous cycle or after ovariectomy or hormone replacement. AT receptors were characterized as of the AT1 type, since they were displaced by the selective AT1 antagonist DuP 753 and not by the AT2 competitor PD 123177. There were marked changes in the concentration of AT1 receptors during the estrous cycle, with highest numbers in metestrus, lower in estrus and diestrus, and lowest during proestrus. Estrogen replacement in ovariectomized rats decreased AT1 receptor number in the anterior pituitary. Our results indicate a dual effect of estrogen on anterior pituitary AT, physiologically on AT receptor expression and pharmacologically on ACE activity.

Angiotensin II↗
PubMed1992

Balloon angioplasty enhances the expression of angiotensin II AT1 receptors in neointima of rat aorta.

Angiotensin II is a vasoactive peptide and may act as a growth factor in vascular smooth muscle cells. Experimental injury of the rat aorta causes rapid migration of medial smooth muscle cells and their proliferation resulting in the formation of neointima. We have examined, using quantitative autoradiography, the expression of angiotensin II receptor subtypes AT1 and AT2, and angiotensin-converting enzyme, in the neointima formed in the rat thoracic aorta 15 d after balloon-catheter injury. In contrast to the normal aortic wall, which contained both AT1 and AT2 receptors (80% and 20%, respectively), neointimal cells expressed almost exclusively angiotensin II AT1 receptors. The apparent number of these receptors was fourfold higher in the neointima compared to that in the normal aortic wall. The affinities of the neointimal receptors to angiotensin II or to the AT1 receptor antagonist, losartan, were not different from those in the normal aortic wall. Angiotensin-converting enzyme binding in the neointima was not different from that in the media of the uninjured aorta. Our data suggest that angiotensin II AT1 receptors may have a significant role in injury-induced vascular smooth muscle proliferation and migration.

Angioplasty, Balloon↗
PubMed1992

Melatonin-binding sites in brain and caudal arteries of the female rat during the estrous cycle and after estrogen administration.

Melatonin-binding sites were studied by quantitative autoradiography in brain and caudal (tail) arteries and in selected brain areas of cycling female rats, ovariectomized rats, and ovariectomized rats treated with estradiol. In the caudal artery, the number of melatonin-binding sites was significantly lower during proestrus, estrus, and metestrus than during diestrus. In ovariectomized rats, melatonin binding to the caudal artery was similar to that found during proestrus, estrus, and metestrus, and a further decrease in the receptor number was produced by estradiol replacement. Similarly, melatonin binding in anterior cerebral arteries was higher during diestrus than at other stages of the estrous cycle. In ovariectomized rats, estradiol replacement also resulted in decreased melatonin binding in anterior cerebral arteries. Conversely, no changes in the number of melatonin-binding sites were observed in the suprachiasmatic nucleus or the area postrema during the estrous cycle, in ovariectomized rats, or after estradiol replacement. The present results suggest that in the female rat, reproductive hormones modulate the expression of cerebral and caudal arterial melatonin-binding sites.

Animals↗
PubMed1989

Prevalence, detection and referral of psychiatric morbidity in general medical patients.

Twenty seven per cent of medical emergency admissions were found to have diagnosable psychiatric disorders, mostly mild. Although ward staff assessed 31.1% of admissions as having emotional or psychological problems, only a minority had diagnosable psychiatric disorders. Few patients were referred for specialist psychiatric help. This partly reflected the milder nature of problems identified by ward staff, and partly indifference to psychiatry.

Adult↗
PubMed1984

Forensic psychiatric assessments in the Northwest territories.

This paper is an analysis of the psychosocial and forensic factors leading to legal referrals to a northern mental health service. It was found, not surprisingly, that most criminal acts were associated with alcoholism, personality disorders, and low socioeconomic status. Young native males figured prominently in both violent and property crimes. Rape offenses and major psychopathology appeared to be more common among Inuit referrals. The influence of rapid culture change and psychosocial and biologic predisposition to the deleterious effects of alcohol were considered relevant criminogenic factors. It was also felt that the high Inuit referral rate might have been related to their willingness to accept consultation and discuss symptoms of mental illness.

Acculturation↗
PubMed1983

Histamine-induced prolactin release: pharmacological characterization of receptors in male rats.

Studies were undertaken to investigate the nature of receptors involved in the prolactin-releasing action of histamine in male rats. The increase of plasma prolactin levels induced by third-ventricle injection of histamine was blocked by intraventricular injection of ranitidine, an H2-antagonist, but not by systemic administration of mepyramine, an H1-antagonist. The H2-histamine agonists 4-methylhistamine and Dimaprit, given intraventricularly in unrestrained and ether-anesthetized rats, enhanced prolactin release. The effect of 4-methylhistamine was dose-dependent, whereas Dimaprit had opposite effects depending on the dose. In low doses, Dimaprit decreased whereas in higher doses it increased plasma prolactin levels. The stimulatory effects of both agonists, similar to those produced by histamine itself, were blocked by metiamide (H2-antagonist), but not by intraventricular mepyramine. High doses of mepyramine only partially decreased the effects of 4-methylhistamine. Ranitidine was able to prevent the prolactin response to 4-methylhistamine. The selective H1-histamine agonist 2,2-pyridylethylamine had no action on prolactin release. 2-Methylhistamine, which exhibits predominantly H1-mediated actions, increased the release of prolactin. Its effect, however, was blocked by low doses of metiamide and was obtained at higher concentrations than 4-methylhistamine. Mepyramine prevented 2-methylhistamine action only at high doses. It is concluded that the increased release of prolactin evoked by histamine in male rats is mainly due to its action on H2-receptors. In addition, the results altogether indicate that H1-receptors have not a significant participation.

Anesthesia↗
PubMed1983

Psychodynamics of spirit possession among the Inuit.

Three cases of spirit possession were studied to determine common underlying psychodynamic factors. The spirits were believed to represent culture bound defense mechanisms, and attempts at problem solving in individuals suffering from unresolved conflicts. These being anomic anxiety, dependency, sexual identity and aggression. The symptoms, therefore, were considered to be attempts at conflict resolution. Furthermore the psychodynamic process is described as a transition phase in psychic development between externalization and internalization of intrapsychic distress or collective versus individual ego solutions to life stress. As such, therapy will be facilitated by knowledge of myths and customs and culturally significant methods of healing.

Adult↗
PubMed1980

Acculturation and mental disorder in the Inuit.

The phenomenon of acculturation stress is described with particular reference to the subsequent development of the transitional role conflict. The adolescent and young adult male Eskimo is especially susceptible to the anxiety generated by the process of acculturation and it is the interaction of this external stress with the bio-psychosocial characteristics of the individual within his ecological group, that may lead to an increased incidence of mental disorder. The clinical picture that develops will depend on the complex interaction of this psychosocial stressor and the level of ego development and its accompanying defence and coping strategies. We see how the development of manifest psychopathology in two young Inuit males was intimately associated with the stresses of acculturation acting upon personalities characterized by a low self-esteem and negative self-image, feelings of emasculation and a state of anomie. Coping and defensive strategies exhibited both similarities (drugs, alcohol, withdrawal, actin out) and differences (psychosis versus dissociation). The value of modified supportive therapy with continuity of care aimed at increasing self-esteem through sublimation, identification, reduction of dependency and encouragement of growth and autonomy is described, as are measures aimed at primary prevention.

Acculturation↗