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Dive into the research topics where Virginia K. Weise is active.

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Featured researches published by Virginia K. Weise.


Neurology | 1981

Pharmacologic distinction of different orthostatic hypotension syndromes

Ronald J. Polinsky; Irwin J. Kopin; Michael H. Ebert; Virginia K. Weise

We studied the pressor responses to vasoactive agents in patients with orthostatic hypotension. Greater-than-normal slopes of the stimulus-response curves in patients with multiple system atrophy (Shy-Drager syndrome) and idiopathic orthostatic hypotension (IOH) were consistent with deficient reflex modulation. Patients with IOH also had a shift to the left of the plasma norepinephrine-blood pressure curves, suggesting ‘denervation supersensitivity.’This was consistent with the deficient plasma norepinephrine response to tyramine in these patients. Patients in whom orthostatic hypotension is attended by tachycardia are subsensitive to administered catecholamines, and may suffer from deficient effector organ responsivity.


Life Sciences | 1976

Assay of catecholamines in human plasma: Studies of a single isotope radioenzymatic procedure

Virginia K. Weise; Irwin J. Kopin

Abstract The sensitive specific radioenzymatic procedure for determination of catecholamines originally described from our laboratory by Coyle and Henry (1) has been optimized for use in assay of human plasma levels of dopamine, norepinephrine and epinephrine. Dopamine and the total of norepinephrine and epinephrine are assayed by 0-methylation while norepinephrine is determined by N-methylation. Epinephrine is calculated from the difference between the 0-methylation and N-methylation procedures. In a group of 13 normal subjects, plasma levels of epinephrine were found to be 67 ± 9.2 pg/ml, norepinephrine 208 ± 16.9 pg/ml and dopamine 33 ± 8.1 pg/ml. Dopamine determinations are of low reliability because of relatively high blanks and necessary corrections.


Journal of Neurochemistry | 1992

Regulation of Tyrosine Hydroxylase and Dopamine β‐Hydroxylase mRNA Levels in Rat Adrenals by a Single and Repeated Immobilization Stress

Anne McMahon; Richard Kvetňansk; Koki Fukuhara; Virginia K. Weise; Irwin J. Kopin; Esther L. Sabban

Abstract: Adrenal catecholamines are known to mediate many of the physiological consequences of the “fight or flight” response to stress. However, the mechanisms by which the long‐term responses to repeated stress are mediated are less well understood and possibly involve alterations in gene expression. In this study the effects of a single and repeated immobilization stress on mRNA levels of the adrenal catecholamine biosynthetic enzymes, tyrosine hydroxylase and dopamine β‐hydroxylase, were examined. A repeated 2‐hr daily immobilization for 7 consecutive days markedly elevated both tyrosine hydroxylase and dopamine β‐hydroxylase mRNA levels (about six‐ and fourfold, respectively). In contrast, tyrosine hydroxylase but not dopamine β‐hydroxylase mRNA levels were elevated immediately following a single immobilization. The elevation in tyrosine hydroxylase mRNA with a single immobilization was as high as with seven daily repeated immobilizations. This elevation was not sustained and returned toward control values 24 hr later. Both tyrosine hydroxylase and dopamine β‐hydroxylase mRNA levels were elevated immediately following two daily immobilizations to levels similar to those observed after seven immobilizations and were maintained 24 hr later. The results indicate that both tyrosine hydroxylase and dopamine β‐hydroxylase mRNA levels are elevated by stress; however, the mechanism and/or timing of their regulation are not identical.


Journal of Neurochemistry | 1992

Effects of Handling or Immobilization on Plasma Levels of 3,4-Dihydroxyphenylalanine, Catecholamines, and Metabolites in Rats

Richard Kvetňansk; David S. Goldstein; Virginia K. Weise; Courtney Holmes; Katalin Szemeredi; Gyorgy Bagdy; Irwin J. Kopin

Abstract: In conscious animals, handling and immobilization increase plasma levels of the catecholamines norepinephrine (NE) and epinephrine (EPI). This study examined plasma concentrations of endogenous compounds related to catecholamine synthesis and metabolism during and after exposure to these stressors in conscious rats. Plasma levels of 3,4‐dihydroxyphenylalanine (DOPA). NE, EPI, and dopamine (DA), the deaminated catechol metabolites 3,4‐dihydroxyphenylglycol (DHPG) and 3,4‐dihydroxyphenylacetic acid (DOPAC), and their O‐methylated derivatives methoxyhydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were measured using liquid chromatography with electrochemical detection at 1,3, 5, 20, 60, and 120 min of immobilization. By 1 min of immobilization, plasma NE and EPI levels had already reached peak values, and plasma levels of DOPA, DHPG, DOPAC, and MHPG were increased significantly from baseline, whereas plasma DA and HVA levels were unchanged. During the remainder of the immobilization period, the increased levels of DOPA, NE, and EPI were maintained, whereas levels of the metabolites progressively increased. In animals immobilized briefly (5 min), elevated concentrations of the metabolites persisted after release from the restraint, whereas DOPA and catecholamine levels returned to baseline. Gentle handling for 1 min also significantly increased plasma levels of DOPA, NE. EPI, and the NE metabolites DHPG and MHPG, without increasing levels of DA or HVA. The results show that in conscious rats, immobilization or even gentle handling rapidly increases plasma levels of catecholamines, the catecholamine precursor DOPA, and metabolites of NE and DA, indicating rapid increases in the synthesis, release, reuptake, and metabolism of catecholamines.


Journal of Neurochemistry | 2002

Increase in Rat Adrenal Phenylethanolamine N-Methyltransferase mRNA Level Caused by Immobilization Stress Depends on Intact Pituitary - Adrenocortical Axis

Emil Viskupic; Richard Kvetnansky; Esther L. Sabban; Koki Fukuhara; Virginia K. Weise; Irwin J. Kopin; Joan P. Schwartz

Abstract: The effects of a single and of repeated immobilization stress on the expression of the final enzyme involved in epinephrine biosynthesis, phenylethanolamine N‐methyltransferase (PNMT), are described. A single immobilization (whether lasting 5 or 120 min) caused a severalfold increase of the adrenal PNMT mRNA level as measured 2 h after the beginning of the procedure. This elevation was of a transient nature, peaked 3–6 h after the 2‐h immobilization, and returned to control values by 12 h after the stress. When the animals were immobilized for 2 h/day for seven consecutive days, an increase in content of PNMT mRNA of a similar magnitude was observed, which persisted for at least 2 days after the seventh immobilization. The immobilization‐induced increase was completely abolished in hypophysectomized animals, whereas adrenal denervation failed to prevent it. These data suggest that the immobilization‐induced increase in adrenal PNMT mRNA level depends primarily on pituitary‐adrenocortical regulation.


Life Sciences | 1975

Plasma catechomamines and dopamine-β-hydroxylase activity in spontaneously hypertensive rats

Michael F. Roizen; Virginia K. Weise; Horst Grobecker; Irwin J. Kopin

Abstract Levels of plasma norepinephrine and total catecholamines in spontaneously hypertensive rats bred from a normotensive Kyoto strain of Wistar rats increase between their 8th to 12th week post utero concomitant with the development of hypertension, but levels of plasma norepinephrine are not significantly different between the spontaneously hypertensive strain, a normotensive Kyoto strain and a N.I.H. strain of Wistar rats at either 8 or 12 weeks of age. Plasma total catecholamine levels in the spontaneously hypertensive strain are significantly higher at 12 weeks of age than those in either control strain, while plasma levels of dopamine-β-hydroxylase show no consistant relationship between the three strains. It, therefore, appears unlikely that increased sympathetic neuronal activity is an etiological factor in this form of hypertension.


Clinica Chimica Acta | 1961

Determination of urinary 3-methoxy-4-hydroxymandelic acid in man

Virginia K. Weise; Roger K. McDonald; Elwood H. Labrosse

Abstract A precise and reliable method for the determination of 3-methoxy-4-hydroxy-mandelic acid (VMA) is described. This method utilizes a radioactive tracer and ion exchange fractionation. Normal values for urinary excretion of VMA are reported for male and female volunteer subjects.


Life Sciences | 1979

Strain differences in rat adrenal biosynthetic enzymes and stress-induced increases in plasma catecholamines

Richard McCarty; Gad M. Gilad; Virginia K. Weise; Irwin J. Kopin

Abstract We have examined in two inbred rat strains basal and stress-induced increases in plasma levels of epinephrine (EPI) and norepinephrine (NE) and compared these with activities of the adrenal enzymes involved in the synthesis of catecholamines. There were no differences in basal levels of NE and EPI in plasma of adult male rats of the Wistar-Kyoto (WKY) and Brown-Norway (B-N) strains. However, following 5 min. of intermittent footshock, plasma levels of both catecholamines were twice as high in WKY rats as in B-N rats. In the adrenals of unstressed rats, activities of tyrosine hydroxylase and dopamine-beta-hydroxylase were significantly higher in B-N rats. In addition, the adrenal weights and the contents of NE but not EPI were greater in B-N rats. Thus, in these two rat strains, the capacity of the adrenal gland to synthesize and store catecholamines appeared to be inversely related to plasma levels of NE and EPI after stress. The differences between the strains appeared to be due to differences in the rates of removal of catecholamines from the peripheral circulation as well as to differences in the rate of release of catecholamines from the sympatho-adrenal medullary system. Thus biosynthetic enzyme activities need not be related directly to the capacity to release and elevate plasma levels of catecholamines following stressful stimulation.


Journal of Neuroendocrinology | 1996

Effects of Continuous and Intermittent Cold (SART) Stress on Sympathoadrenal System Activity in Rats

Koki Fukuhara; Richard Kvetnansky; Virginia K. Weise; Hiroyuki Ohara; Ryozo Yoneda; David S. Goldstein; Irwin J. Kopin

We compared sympathoadrenal responses to intermittent cold (SART) stress (in which cold exposure is interrupted by 4‐hourly intervals daily at room temperature) with those to continuous cold (−3°C) stress. Plasma levels of dihydroxyphenylalanine (DOPA), catecholamines and their metabolites as well as tyrosine hydroxylase (TH) activities in sympathetically innervated tissues were examined in rats exposed to each stressor for 1 day or for 5 days. Neither SART nor continuous exposure to cold for 1 day or 5 days altered plasma epinephrine (EPI) levels. However, norepinephrine (NE) and dihydroxyphenylglycol (DHPG) levels increased markedly during exposure to these stressors. On the first day of SART or continuous cold stress, NE levels were increased similarly, but the increments in DHPG levels were greater during SART stress. Since DHPG is formed in neurons, neural reuptake of NE may be more enhanced on the first day of SART stress than on the first day of continuous cold stress. After 5 days of SART stress plasma NE levels were significantly higher than those found after 5 days of continuous cold exposure. Plasma levels of DHPG were elevated to the same extent in both 5 days SART‐ and continuously cold‐stressed rats, whereas plasma levels of methoxyhydroxyphenylglycol (MHPG) increased only by 5 days SART stress. Even at 1 h after the removal from 5 days SART stress, increased plasma levels of NE, DHPG and MHPG were still evident. These results suggest that 5 days SART stress elevates extraneuronal O‐methylation of DHPG, and that NE turnover is more greatly increased by SART stress than by continuous cold stress. Plasma levels of DOPA, dopamine, dihydroxyphenylacetic acid and homovanillic acid also increased after either SART or continuous cold stress for 1 day and 5 days. Adrenal TH activities were significantly increased in rats exposed to SART or continuous cold stress for 1 day and 5 days, but in brown fat TH activity was elevated only in rats exposed to 5 days of continuous cold. Both SART and continuous cold stress are selective and potent stimuli for activation of the sympathoneural system, apparently without significant adrenomedullary EPI release. The increase of TH activity in the brown fat pad as well as of plasma NE and its metabolites is probably a result of adaptation to cold. It appears that even short intervals of return to a normal environmental temperature, as in SART, are sufficient to diminish sympathetic adaptation to cold.


American Heart Journal | 1981

Changes in peripheral vascular and cardiac sympathetic activity before and after coronary artery bypass surgery: Interrelationships with hemodynamic alterations

Young Dae Kim; Michael Jones; S. T. Hanowell; John P. Koch; David Eric Lees; Virginia K. Weise; Irwin J. Kopin

The plasma catecholamine levels obtained simultaneously from radial artery (A), pulmonary artery (MV), brachial vein (PV), and coronary sinus (CS) were measured concurrent with hemodynamic determinations during coronary artery bypass graft (CABG) operations. Arterial catecholamine levels decreased after induction of anesthesia and increased after sternotomy; changes in veno-arterial norepinephrine (NE) differences ([PV-A]ne, [MV-A]ne, and [CS-A]ne) were of the same magnitude and direction, suggesting that NE release from various organs was of the same extent. After operation, arterial NE increased further, but the veno-arterial NE differences were in striking contrast; [PV-A]ne became markedly positive, whereas [CS-A]ne became markedly negative, indicating that NE release from extremity peripheral vasculature increased markedly while cardiac NE release decreased. These differential changes in regional sympathetic activity appear to be related to postoperative hypertension (HT) and low cardiac output (CO). There were close relationships of changes in [MV-A]ne to mean arterial pressure (r = 0.78, p less than 0.001) and systemic vascular resistance (r = 0.62, p less than 0.010, suggesting that the sympathetic nervous system plays an important role in CABG perioperative hemodynamic alterations.

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Irwin J. Kopin

National Institutes of Health

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Roger K. McDonald

National Institutes of Health

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H. Grobecker

University of Regensburg

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David S. Goldstein

National Institutes of Health

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Juan M. Saavedra

Georgetown University Medical Center

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Koki Fukuhara

National Institutes of Health

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Courtney Holmes

National Institutes of Health

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Jose M. Musacchio

National Institutes of Health

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