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Biomedical subjects

D E Stewart

Publications and source records attributed to D E Stewart.

At least 109 records · Page 6Linked to original sources
PubMed1987

Anorexia nervosa, bulimia, and pregnancy.

Of 74 women previously treated for anorexia nervosa or bulimia, 15 had conceived 23 pregnancies when assessed at follow-up. The status of the eating disorder, course of pregnancy and delivery, infant health, and postpartum adjustment are described. Women in whom eating disorders were in remission at conception had greater maternal weight gain and babies with higher birth weights and 5-minute Apgar scores than women who conceived while they still had symptoms of restricting anorexia nervosa or bulimia. Women who had symptoms of eating disorders at conception also had continuance or worsening of these symptoms during pregnancy and the postpartum year. We recommend delay of pregnancy until the eating disorder is truly in remission.

Adaptation, Psychological↗
PubMed1986

Improvement in bronchial hyper-responsiveness in patients with moderate asthma after treatment with a hypnotic technique: a randomised controlled trial.

A prospective, randomised, single blind, and controlled trial of a hypnotic technique was undertaken in 39 adults with mild to moderate asthma graded for low and high susceptibility to hypnosis. After a six week course of hypnotherapy 12 patients with a high susceptibility score showed a 74.9% improvement (p less than 0.01) in the degree of bronchial hyper-responsiveness to a standardised methacholine challenge test. Daily home recordings of symptoms improved by 41% (p less than 0.01), peak expiratory flow rates improved by 5.5% (p less than 0.01), and use of bronchodilators decreased by 26.2% (p less than 0.05). The improvement in bronchial hyper-reactivity occurred without a change in subjective appreciation of the degree of bronchoconstriction. A control group 17 patients and 10 patients undergoing treatment with low susceptibility to hypnosis had no change in either bronchial hyper-responsiveness or any of the symptoms recorded at home. This study shows the efficacy of a hypnotic technique in adult asthmatics who are moderately to highly susceptible to hypnosis.

Adult↗
PubMed1986

Postpartum psychiatric disorders.

Postpartum blues, postpartum neurotic depression and puerperal psychoses have distinct clinical features; they affect women in all social classes and in all cultures, and despite numerous studies they have not been linked definitively with any biologic or psychosocial variables. The only possible exception is puerperal psychosis, which emerges much more often in women with a personal or family history of a bipolar affective disorder than in women without, a finding that probably explains the reluctance of some researchers to recognize puerperal psychotic episodes as distinct from psychotic episodes at other times. If postpartum blues last longer than 2 weeks and are disabling they are classified as neurotic depression and warrant treatment, often requiring both psychosocial approaches and psychotropic drug therapy. Antidepressants, major tranquillizers, electroconvulsive therapy and lithium have proved effective in the treatment of postpartum psychoses, depending on the symptoms. Both lithium and diazepam have been reported to cause deleterious side effects on breast-fed infants, and as the side effects of other psychotropic drugs given to a nursing mother are imperfectly understood, bottle feeding seems prudent.

Adult↗
PubMed1986

Regulation of beta-adrenergic receptor density in the non-innervated and denervated embryonic chick heart.

Factors which regulate beta-adrenergic receptor density in non-innervated and denervated embryonic tissues have not been fully elucidated. In the present study, the effects of exposure to isoproterenol and propranolol on beta-adrenergic receptor density in the non-innervated (preneural) and partially innervated (neural) embryonic chick heart are examined. In addition, the effects of chemical and surgical sympathectomy on cardiac beta-adrenergic receptor density in the chick embryo are investigated. (125I)-pindolol was used as a receptor probe. The density of beta-adrenergic receptors in the embryonic chick heart peaks on incubation day 9 (664 fmols/mg protein) and then decreases by more than 80% by incubation day 19. Administration of propranolol or isoproterenol on incubation days 4 to 6 results in no change or a decrease (to 62% of control), respectively, in receptor density on incubation day 7. Administration of propranolol on incubation days 10 to 19 causes an increase (to 230% of control) in beta-adrenergic receptor density on day 20. Administration of isoproterenol on incubation days 10 to 16 results in a decrease (to 26% of control) in receptor density on day 17. Neither chemical sympathectomy, produced by administration of 6-hydroxydopamine, nor surgical sympathectomy, produced by removal of premigratory neural crest cells, significantly alters cardiac beta-adrenergic receptor density from control values. Administration of adrenergic drugs produces a greater change in beta-adrenergic receptor density after sympathetic innervation (day 10) than in preneural hearts. This indicates that sympathetic nerves influence the properties of beta-adrenergic receptors during embryonic development.

Animals↗
PubMed1986

Cyclic AMP in normal and sympathetically aneural chick hearts during development.

Basal levels of cyclic adenosine monophosphate (cAMP) were measured in embryonic chick hearts at various times during development. Basal cAMP was highest on incubation day 5 and decreased throughout the remaining incubation period. Cyclic AMP could not be stimulated above basal level by intravenous in ovo administration of isoproterenol or tyramine on incubation day 5; however, there was a decrease in cAMP 2 mins after intravenous injection which was identical to the decrease in cAMP in controls injected with saline. Heart rate decreased following intravenous injection of saline on incubation day 5, but a similar decrease was not observed following intravenous isoproterenol injection. Functional sympathetic innervation of the heart does not occur until incubation day 16, and this fact is responsible for the insensitivity to tyramine stimulation on incubation day 5. Although the level of cAMP could not be stimulated above basal level on incubation day 5, beta-antagonists caused a decrease in the level of cAMP, with no decrease in heart rate. These observations indicate that the beta-receptor is coupled to adenylate cyclase on incubation day 5 but it is questionable whether adenylate cyclase is effectively coupled to heart rate. Isoproterenol and tyramine caused a significant elevation in cardiac cAMP and heart rate on incubation day 17 following intravenous in ovo injection. Hearts made sympathetically aneural by removal of premigratory neural crest responded to isoproterenol but not tyramine on incubation day 17 which demonstrates that the morphologically aneural hearts are also functionally aneural.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Hemodynamic changes in chick embryos precede heart defects after cardiac neural crest ablation.

Neural crest cells are known to contribute to the normal architecture of the heart and aortic arch arteries. Ablation of neural crest cells over somites 1 to 3 in the chick embryo prevents conotruncal septation and results in persistent truncus arteriosus. To determine whether a deficiency of cardiac neural crest cells produces hemodynamic changes prior to the development of identifiable structural defects in the heart, we measured dorsal aortic blood velocity and vitelline artery blood pressure in lesioned and control embryos at a period of cardiac morphogenesis prior to septal formation. The internal diameter of the dorsal aorta at the level of the sinus venosus and the internal diameter of the aortic arch arteries at their midpoints were measured in embryos at Stage 18 of development using a filar micrometer eyepiece and a dissecting microscope. Embryos with neural crest lesions had significantly greater dorsal aortic blood flow velocity than control embryos. In addition, embryos lacking cardiac neural crest had significantly lower systolic and diastolic blood pressures than control embryos. There was no difference in heart rate, dorsal aortic diameter or internal diameter of the aortic arch arteries between lesioned and control embryos. Scanning electron micrographs revealed no gross morphological differences in cardiac looping or conotruncal wall development between lesioned and control embryos; however, embryos with cardiac neural crest ablations developed markedly hypoplastic 4th pharyngeal arches. This data suggests that hemodynamic changes precede the onset of structural heart defects in embryos with cardiac neural crest ablations.

Animals↗
PubMed1986

The rational use of psychotropic drugs in pregnancy and postpartum.

When a pregnant woman or nursing mother requires psychotropic medication, one must consider the effect of such medications on the fetus or baby. The authors review the evidence for teratogenic effects of such drugs given during pregnancy, toxic or withdrawal effects in the newborn and dangers to the breast-fed baby. Suggestions are made for judicious use of psychotropic drugs in pregnant or nursing women.

Abnormalities, Drug-Induced↗
PubMed1986

Iatrogenic parkinsonism in Huntington's chorea.

This case report describes a 63 year old woman with a nineteen year history of Huntington's Chorea who had been successfully treated with tetrabenazine for 9 years. During a hospital admission for an unrelated medical illness, she was given two doses of chlorpromazine 25 mg for a vascular headache and within hours became mute, extremely rigid, and unable to move or swallow. The consultation psychiatrist confirmed the diagnosis of severe drug-induced parkinsonism by intramuscular injection of benztropine mesylate which resulted in a dramatic immediate improvement. Both chlorpromazine and tetrabenazine were discontinued and the patient's severe parkinsonian symptoms completely abated on oral benztropine mesylate. Tetrabenazine alone, was restarted after 48 hours to control her Huntington's Chorea and there was no recurrence of parkinsonism. (Past history revealed the patient to have tolerated the same doses of chlorpromazine and tetrabenazine when given separately.) Previous literature reports concurrent safe use of antipsychotics with tetrabenazine, but this case report would suggest caution, and early discontinuance in the event of parkinsonism.

Chlorpromazine↗
PubMed1985

Psychiatric assessment of patients with "20th-century disease" ("total allergy syndrome").

"Twentieth-century disease", or "total allergy syndrome", is a condition attributed to hypersensitivity to the environment that may sometimes be seen as so serious that the patient is incapable of living in the modern world. Although the popular media frequently carry stories about it, there is little scientific literature. It is diagnosed by clinical ecologists, who maintain, among other theories, that susceptible individuals experience an overload in assaults by artificial materials in the environment. The patients usually have multiple ill defined symptoms for which no organic cause can be found, but they vigorously resist psychiatric referral, as they attribute their symptoms to allergy. A group of 18 patients who were purportedly suffering from 20th-century disease were referred to a university psychiatric consultation liaison service. They virtually all had a long history of visits to physicians, and their symptoms were characteristic of several well known psychiatric disorders. The case histories and management of three of them are presented. Although this group of patients may have been atypical in that they had more severe psychologic symptoms, the experience indicates that a psychiatric diagnosis ought to be considered. The symptoms of 20th-century disease have much in common with other conditions known to physicians for centuries.

Adult↗
PubMed1985

Endogenous tyrosine hydroxylase activity in the developing chick heart: a possible source of extraneuronal catecholamines.

The source of catecholamines in the developing chick heart was investigated by using catecholamine assays and tyrosine hydroxylase assays on hearts from normal and chemically-sympathectomized chick embryos. A biochemical index of sympathetic nerve development in the heart was obtained by monitoring the ability of sympathetic nerves in the atria to take up [3H]-norepinephrine in vitro. Specific neuronal uptake of [3H]-norepinephrine in atria was first detected on incubation day 11 and increased throughout the incubation period. High performance liquid chromatography with electrochemical detection was used to measure the norepinephrine concentration and content of embryonic hearts. The cardiac norepinephrine concentration fluctuated throughout the incubation period but was particularly low (0.01 +/- 0.005 ng/mg wet wt) on incubation days 10 to 13, coincident with the arrival of sympathetic nerves in the heart. The highest norepinephrine concentration was measured on incubation day 7 (2.09 +/- 0.50 ng/mg wet wt) prior to the arrival of sympathetic nerves in the heart. Sympathetic nerve axotomy produced by chronic treatment with 6-hydroxydopamine reduced [3H]-norepinephrine uptake in atria and norepinephrine concentration in whole hearts on incubation day 20 to 33 and 47% of control, respectively. Tyrosine hydroxylase activity was detected in normal hearts on incubation day 7, 3 to 4 days before the heart is innervated by sympathetic nerves. Tyrosine hydroxylase activity persisted in the heart on incubation day 20, despite treatment with 6-hydroxydopamine on incubation days 13 to 19. The tyrosine hydroxylase activity in 6-hydroxydopamine lesioned hearts was not significantly different from saline-treated controls. This data indicates that tyrosine hydroxylase activity is present in the immature chick heart prior to the arrival of sympathetic innervation and following chemical sympathectomy; hence, an extraneuronal source of tyrosine hydroxylase, the rate limiting enzyme for catecholamine biosynthesis, exists in the embryonic chick heart.

Animals↗
PubMed1985

Arrhythmogenic potential of diuretic induced hypokalaemia in patients with mild hypertension and ischaemic heart disease.

In view of evidence suggesting an association of mild hypokalaemia with cardiac arrhythmia, the arrhythmogenic potentials of potassium losing and potassium sparing diuretic treatments were compared in a controlled prospective crossover study of 10 patients with mild hypertension and ischaemic heart disease. Mean (SEM) plasma potassium was 4.3(0.06) mmol/l and 3.3(0.07) mmol/l after potassium sparing and potassium losing treatments respectively. Blood pressure and volume depletion as assessed by weight change, plasma renin activity, and noradrenaline concentrations did not differ significantly in the two treatment periods. The potassium losing treatment phase was associated with an increased frequency of ventricular extrasystoles, a higher Lown grading during ambulatory electrocardiographic monitoring, prolonged duration and decreased phase 0 velocity of the monophasic action potential, a prolonged ventricular effective refractory period, and increased myocardial electrical instability as assessed by programmed ventricular stimulation. It is concluded that minor changes in plasma potassium concentration are associated with increased ventricular electrical instability in patients with ischaemic heart disease. Mild hypokalaemia in such patients may predispose to life threatening arrhythmias and should be avoided.

Amiloride↗
PubMed1985

Combining motherhood with psychiatric training and practice.

Psychiatric residency or practice is difficult to combine with motherhood. The experiences of 82 women psychiatrists surveyed in the last year (47 residents and 35 staff doctors) are reviewed in a number of related areas--the difficulties of pregnancy, maternity leave, child rearing and the conflicts between motherhood and practicing psychiatry. Part-time residency is explored from both the resident's and hospital's perspective. Suggestions to make practice or residency more compatible with child rearing are discussed. Other issues such as work-based day care, realistic tax credit for child care expenses, and the difficulties of obtaining reliable and good home help and child care are reviewed. There are numerous conflicts for women psychiatrists who work while their children are young and these problems need to be acknowledged and addressed by the profession. It is noteworthy that as well as a supportive spouse and good child care, the attitudes of colleagues and supervisors and the need for good role models were frequently cited as being critical to the success of combining a psychiatric career with motherhood. As more women enter the profession (approximately 50% of psychiatric residents in Canada are now female, and more than 50% of them plan to combine children with their profession at some stage of their career) the need to find creative and workable solutions to these problems becomes more pressing.

Attitude of Health Personnel↗
PubMed1984

The use of intravenous disopyramide for the conversion of supraventricular tachyarrhythmias.

A study of the efficacy of intravenous disopyramide in the conversion of supraventricular tachyarrhythmias to sinus rhythm was undertaken in a group of 23 patients with a variety of cardiological diagnoses. An intravenous bolus (2 mg/kg) followed, where appropriate, by an infusion (0.4 mg/kg) resulted in an overall conversion rate of 63% (43% in atrial fibrillation, 50% in atrial flutter, 89% in atrial tachycardias). Serious cardiotoxic side effects occurred in 15%. The study shows that such a regime is useful in a selected group of patients provided certain precautions are observed.

Adolescent↗
PubMed1983

Neural crest cells contribute to normal aorticopulmonary septation.

By analyzing the hearts of quail-chick chimeras, it was found that neural crest cells at the level of occipital somites 1 to 3 migrate to the region of the aorticopulmonary septum. Bilateral removal of this neural crest population prior to migration causes malformation of the aorticopulmonary septum resulting in common arterial outflow channels or transposition of the great vessels.

Animals↗
PubMed1983

Effect of experimental hyperphenylalaninemia on biogenic amine synthesis at later stages of brain development.

The effects of experimental hyperphenylalaninemia on catecholamine and serotonin synthesis in brain at a later stage of brain development were investigated. A group of 35-day-old rats treated with normal chow supplemented with 5% Phe + 0.4% alpha-methylphenylalanine, alpha MP, for the previous 10 days showed decreases in dopa, norepinephrine, and epinephrine versus controls. A group treated with a normal diet supplemented with 0.4% alpha MP showed similar decreases and these differences could be attributed to the presence of the phenylalanine hydroxylase and tyrosine hydroxylase inhibitor, alpha MP, rather than the hyperphenylalaninemia condition. No differences in dopamine were observed. Serotonin and 5-hydroxyindoleacetic acid (5HIAA) were decreased 50% in the HyPhe condition and were unaffected in the presence of alpha MP alone, indicating that the decreases in serotonin and 5HIAA were due to the increases in phenylalanine rather than the presence of the inhibitor. These abnormalities in serotonin metabolism at later stages of brain development may be relevant to early discontinuation of dietary therapy in the PKU patient and implies a role in tryptophan supplementation to increase intracerebral serotonin values.

Animals↗