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Biomedical subjects

V Christensen

Publications and source records attributed to V Christensen.

At least 19 recordsLinked to original sources
PubMed2001

[Malignant neuroleptic syndrome or serotonergic syndrome].

The malignant neuroleptica syndrome (MNS) and the serotonin syndrome (SS) can be impossible to differentiate. This case history describes clinical symptoms compatible with either MNS or SS in a 59-year-old schizophrenic male patient, who had been heavily medicated with antipsychotics for several years in close relation to initiation of new treatment with a SSRI compound. The case shows that it is important to have both syndromes in mind when chronically ill patients are treated with several medicaments.

Antipsychotic Agents↗
PubMed2000

Attention to touch modulates activity in both primary and secondary somatosensory areas.

We used fMRI to establish whether attention to touch enhances somatosensory cortical activity. Subjects received somatosensory and visual stimulation and were instructed to attend selectively to one modality during alternating stimulus detection periods interspersed with rest periods during which no stimulus was delivered. The maximum signal change for each task versus rest was measured in anatomically defined regions of interest for each subject. Attended touch produced greater signal change than unattended touch in primary (S1) and secondary (S2) somatosensory cortex. In contrast to the conclusions of some previous studies, we found that the enhancement of activation with attention was at least as great in S1 as in S2. The attentional effect was unilateral in S1 and bilateral in S2 and the somatosensory insula.

Adult↗
PubMed1998

Fishing down marine food webs

The mean trophic level of the species groups reported in Food and Agricultural Organization global fisheries statistics declined from 1950 to 1994. This reflects a gradual transition in landings from long-lived, high trophic level, piscivorous bottom fish toward short-lived, low trophic level invertebrates and planktivorous pelagic fish. This effect, also found to be occurring in inland fisheries, is most pronounced in the Northern Hemisphere. Fishing down food webs (that is, at lower trophic levels) leads at first to increasing catches, then to a phase transition associated with stagnating or declining catches. These results indicate that present exploitation patterns are unsustainable.

Journal Article↗
PubMed1993

Tetrasomy 9p: tissue-limited idic(9p) in a child with mild manifestations and a normal CVS result. Report and review.

Supernumerary isochromosomes resulting in autosomal tetrasomy are rare and have been described only for 12p, 18p, and 9p. Nineteen previous cases of tetrasomy 9p have been reported, and in 6 cases, tissue-specific mosaicism was implied with the i(9p) cell line present exclusively or predominantly in blood. We report on an infant who had apparently normal chromosomes (46,XY) on CVS. He was referred for genetic evaluation because of mild developmental delay and minor anomalies. In 75% of blood cells he had an extra isodicentric 9p chromosome (pter-->q12-->pter). The interpretation of tetrasomy 9p was confirmed by elevated GALT activity. No tetrasomy 9p cells were seen in 100 skin fibroblasts. This case demonstrates the tissue specific mosaicism in tetrasomy 9p which rendered the anomaly undetectable by CVS. It also demonstrates the mild end of the clinical spectrum associated with tetrasomy 9p.

Chromosome Aberrations↗
PubMed1986

The effects of citalopram in single and repeated doses and with alcohol on physiological and psychological measures in healthy subjects.

Citalopram, a selective 5-HT uptake inhibitor with antidepressant properties, was assessed in three studies in 12 healthy subjects using a battery of EEG, psychological, subjective and symptomatic measures. Study A involved the administration of citalopram, 20 mg and 40 mg, amitriptyline 50 mg and placebo in single dose using a balanced cross-over design. The test battery was applied before, and 1 and 3 h after each drug. Citalopram decreased slow-wave EEG activity whereas amitriptyline increased power in most EEG wavebands. Citalopram increased tapping rate and symbol copying whereas amitriptyline impaired these and other psychomotor tasks. Subjectively, amitriptyline was much more sedative than citalopram and produced more complaints of dry mouth. Study B comprised the administration of citalopram in the usual clinical dose of 40 mg, amitriptyline in the low clinical dose of 75 mg and placebo, each given for 9 nights using a balanced cross-over design. The test battery was applied on the first morning (pre-drug) and on the morning after the last nightly dose. None of the physiological tests showed any drug effects. Subjectively, citalopram was associated with feelings of shaking, nausea, loss of appetite and physical tiredness; amitriptyline produced feelings of shaking, nausea, loss of appetite, dryness of mouth, irritability, dizziness and indigestion; in general, amitriptyline effects were more marked than those of citalopram. Plasma samples were taken on the last day and plasma concentrations of both drugs and their metabolites were found to be in the expected range for the regimens used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Left ventricular ejection fraction during anaesthetic induction: comparison of rapid-sequence and elective induction.

A randomized clinical trial was conducted in 14 women, aged 24-60 years, to compare the effects of rapid-sequence induction of anaesthesia and elective induction on heart rate, blood pressure and left ventricular ejection fraction (LVEF). None of the patients suffered from heart or lung diseases, and all were scheduled for hysterectomy. Cuff blood pressure was measured repeatedly by an automatic recording device, and heart rate and LVEF were monitored by a portable nonimaging nuclear probe. In seven patients, a rapid-sequence induction was performed following preoxygenation and with simultaneous injection of thiopentone (5 mg X kg-1) and succinylcholine, without starting manual ventilation until the airway was secured with the endotracheal tube. In another seven patients, elective induction was carried out by sequential administration of the same drugs. Forty seconds after laryngoscopy and intubation mean blood pressure had increased by 38 per cent and heart rate by 29 per cent from preintubation values in the rapid sequence induction group, compared to 30 and 12 per cent respectively, in the elective induction group (p less than 0.05). Similar decreases in LVEF was observed in both groups, from 0.60 to 0.42 in the elective induction group, and from 0.60 to 0.41 in the rapid-sequence induction group. The equal depression of LVEF indicates that laryngoscopy and intubation produce, with both induction regimens, sudden impairment of cardiac function. The more pronounced hypertension and tachycardia observed during rapid-sequence induction suggests a higher myocardial oxygen consumption which may represent a serious additional burden for the poorly perfused heart.

Adult↗
PubMed1986

Lack of effect of intravenous lidocaine on hemodynamic responses to rapid sequence induction of general anesthesia: a double-blind controlled clinical trial.

A double-blind, randomized trial was conducted in 16 women aged 20-48 yr, to assess the effect of intravenous lidocaine on the circulatory responses to rapid sequence induction of general anesthesia. None of the patients suffered from heart or lung diseases, all were scheduled for hysterectomy, and all were premedicated with 0.3 mg/kg diazepam orally 2 hr beforehand. Induction, preceded by preoxygenation, included simultaneous injection of thiopental and succinylcholine, without starting manual ventilation until the airway was secured with the endotracheal tube. Two minutes before laryngoscopy and intubation half of the patients received lidocaine, 1.5 mg/kg, intravenously (IV). The other half received an equal volume of saline. Cuff blood pressure was measured repeatedly by an automatic recording device, and heart rate and left ventricular ejection fraction (LVEF) were monitored by a portable nonimaging nuclear probe. After laryngoscopy and intubation, mean blood pressure increased 46%, heart rate 57%, and the rate pressure product (RPP) 84% from control values in patients given lidocaine, compared to 45, 66, and 113%, respectively, in the saline group (P greater than 0.05). Pronounced, but similar decreases in LVEF were observed in the two groups, to 0.40 from 0.65 in the lidocaine group and to 0.41 from 0.65 in the saline group. In all patients, RPP reached a level considered potentially dangerous to patients with ischemic heart disease. We conclude that lidocaine, 1.5 mg/kg IV, 2 min prior to laryngoscopy and intubation does not prevent hemodynamic reactions evoked by rapid sequence induction.

Adult↗
PubMed1979

Influence of age on the endocrine-metabolic response to surgery.

The pathogenesis of the increased operative risk in elderly patients is unknown. From a theoretical point of view, a change in endocrine-metabolic response might be involved. In the present study, a battery of hormonal and metabolic variables were measured in eight young and eight elderly healthy males undergoing elective inguinal hernial repair under general anesthesia. Blood was drawn before induction of anesthesia, at skin incision, and one, two, and six hours after skin incision. The findings were: 1) Plasma cortisol increase was significantly higher in elderly than in young controls. 2) Plasma renin level was lower in old age, but renin-aldosterone and electrolyte response patterns were alike in the two groups. 3) Thyroid parameters, in terms of serum T4, serum T3, serum rT3, and T3-resin uptake, responded normally to surgery and showed no age-related differences. 4) The hyperglycemic response was not significantly influenced by age indicating unchanged glycoregulatory mechanisms also verified by determinations of plasma catecholamines, cAMP, and insulin. 5) Blood lymphocyte count was constantly lower in elderly than in young and decreased with time, but the age-related difference was not significant. 6) Blood polymorphonuclear leukocytes showed an increase of the same magnitude in both age groups, although at a significantly slower rate in the elderly. It is concluded that age affects some aspects of the initial endocrine-metabolic response to surgery.

Adult↗
PubMed1978

Cardiovascular haemodynamics during enflurane-pancuronium anaesthesia in patients with valvular heart disease.

The effects of enflurane-pancuronium anaesthesia on cardiovascular haemodynamics were studied before operation in six patients with valvular heart disease. A ten per cent decline in cardiac index and a 20 per cent decline in stroke volume were the only changes observed. Mean arterial, pulmonary arterial, contral venous, and pulmonary capillary wedge pressures were unaffected, as were systemic vascular resistance and pulmonary vascular resistance. The authors therefore conclude that enflurane-pancuronium anaesthesia causes only minimal cardiovascular depression in patients with valvular heart disease.

Anesthesia↗
PubMed1978

The effect of propanidid on systemic vascular resistance in man.

We have studied the peripheral vascular effect in man of propanidid 6 mg/kg, administered as a bolus injection during cardiopulmonary by-pass with the aorta cross-clamped and at constant perfusion flow. Ten measurements in eight patients were performed. A decrease was found in systemic vascular resistance: from 150.7 +/- 16.3 to 99.5 +/- 10.1 kPa x s/1. No venous pooling occurred. It is concluded that, in man, propanidid causes a vasodilation which must contribute to the hypotension it causes.

Anesthesia, Inhalation↗
PubMed1978

Percutaneous catheterization of the internal jugular vein.

Two techniques for catheterization of the internal jugular vein are described in detail. In a group of 108 adults and 54 children, catheterization of the internal jugular vein was attempted 168 times. Failure to achieve catheterization occurred 12 times. The success rate for the first 50 patients was 86%, but it increased with experience, and was nearly 96% for the remaining patients. Almost 90% of catherizations were achieved on the first or second attempt. The success rate was understandably lower in the children's group. Catheter malpositioning occurred infrequently (six times) and was most common in the children's group. There were few complications, although two were of a serious nature. The techniques described are straightforward, easy to master and perform, and are recommended as useful additions to the anaesthetist's clinical armamentarium.

Adolescent↗