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Biomedical subjects

J Jacobsen

Publications and source records attributed to J Jacobsen.

At least 19 recordsLinked to original sources
PubMed1992

Reduced left ventricular diameters at onset of bradycardia during epidural anaesthesia.

Pathophysiologic mechanisms of bradycardia during epidural anaesthesia (L3-L4 with 1% lidocaine, 38 ml) were evaluated by studying changes in selected cardiovascular and hormonal parameters. Six of eight subjects (analgesia to T8-T10) remained circulatory stable with no significant changes in heart rate (HR), mean arterial pressure (MAP) and thoracic impedance (TI). In one of two subjects MAP decreased after 25 min from 85 to 50 mmHg (11.3 to 6.7 kPa), HR from 80 to 45 beats.min-1 while thoracic impedance increased from 25.5 to 26.5 ohm. End-systolic diameter (ESD) and end-diastolic diameter (EDD) of the left ventricle determined with echocardiography were reduced from 3.8 to 3.2 cm (17%) and 5.6 to 5.0 cm (11%), respectively. In the other subject MAP decreased after 25 min from 75 to 50 mmHg (10.0 to 6.7 kPa) and HR from 82 to 60 beats.min-1 while thoracic impedance increased from 28.8 to 29.6 ohm. ESD was reduced from 3.8 to 3.3 cm (13%), and EDD from 5.6 to 5.0 cm (11%). Both subjects recovered after infusion of saline and being placed in the head-down position. There were no consistent changes in plasma catecholamines, whereas pancreatic polypeptide increased from 5 and 3 to 152 and 69 pmol.l-1, vasopressin from 3 and 2 to 152 and 46 pmol.l-1, and aldosterone from 282 and 229 to 383 and 485 pmol.l-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Bradycardia during reversible hypovolaemic shock: associated neural reflex mechanisms and clinical implications.

1. Heart rate response to reversible central hypovolaemia can be divided into three stages. In the first stage (corresponding to a reduction of the blood volume by approximately 15%) a modest increase in heart rate (< 100 beats/min) and total peripheral resistance compensate for the blood loss, and a near normal arterial blood pressure prevails (preshock). During the second stage, a reduction of the central blood volume by approximately 30% results in a decrease in heart rate, total peripheral resistance and blood pressure due to activation of unmyelinated vagal afferents (C-fibres) from the left ventricle. In the third stage, blood pressure falls further as haemorrhage continues and tachycardia (> 120 beats/min) is manifest. This stage may proceed into irreversible shock with death from cardiac arrest probably related to the formation of free oxygen radicals. 2. Recognition of the vasodepressor-cardioinhibitory reaction to a reduced circulating blood volume is important and suggests the need for immediate treatment with volume expansion in critically ill patients.

Autonomic Nervous System↗
PubMed1992

Heart rate during haemorrhagic shock.

In a prospective study, heart rate and mean arterial pressure were related to estimated blood loss in 34 consecutive patients aged 23-92 years during resuscitation from haemorrhagic shock. Eighteen patients with a blood loss of less than 31 (1.9 [0.9-3.0] l) (median and range), corresponding to 34 (16-46) % of estimated blood volume, had a heart rate of 83 (60-160) beats min-1 and a mean arterial pressure of 62 (35-73) mmHg. In 16 patients with a blood loss of more than 3 l (4.0 [3.3-5.0] l) corresponding to 89 (35-100) % of the estimated blood volume, heart rate was 120 (110-160) beats min-1 (P < 0.05) and mean arterial pressure 52 (0-70) mmHg (P < 0.05). Six patients died due to severe bleeding (3.1 [2.5-5.0] l) with a heart rate of 129 (110-160) beats min-1 and a mean arterial pressure of 40 (0-70) mmHg. It is concluded that reversible hypovolaemic shock is associated with a relatively low heart rate (approximately 80 beats min-1) and that tachycardia (approximately 120 beats min-1) is associated with profound bleeding. Hypovolaemic shock with tachycardia may represent a transition to an irreversible stage.

Adult↗
PubMed1992

Increased urinary loss of uric acid in adults with acute respiratory failure requiring mechanical ventilation.

INTRODUCTION: The purpose of this study was to test a hypothesis of increased urinary excretion of uric acid as an indicator of adenosine triphosphate (ATP) degradation in adult patients with acute respiratory failure, and to look for a correlation to the clinical outcome. STUDY DESIGN: Prospectively 31 patients with acute respiratory failure were studied. The patients were divided into two groups according to the clinical outcome: the need for solely supplemental oxygen (group 1), death or mechanical ventilation (group 2). METHODS: Uric acid was determined by spectrophotometry. RESULTS: Mean uric acid excretion was 39 mumol/kg (range, 7 to 92 mumol/kg) body weight/per 24 h in group 1 (16 patients) compared with 65 mumol/kg/24 h (range, 8 to 253 mumol/kg/24 h) in group 2 (13 patients were mechanically ventilated, and two patients died). The difference was highly significant (p less than 0.0001). CONCLUSION: Increased amount of urinary uric acid was related to the severity of acute respiratory failure in adults.

Acute Disease↗
PubMed1991

A placebo-controlled trial of maintenance therapy with fluconazole after treatment of cryptococcal meningitis in the acquired immunodeficiency syndrome. California Collaborative Treatment Group.

BACKGROUND AND METHODS: In patients with the acquired immunodeficiency syndrome (AIDS), the rate of relapse after primary treatment for cryptococcal meningitis remains high. We conducted a controlled, double-blind trial to evaluate the efficacy of maintenance therapy with fluconazole. At entry into the study, all participants had sterile cultures of cerebrospinal fluid, blood, and urine after following a standardized course of therapy for culture-proved cryptococcal meningitis. The patients were randomly assigned to take either fluconazole or placebo as maintenance therapy. The dose of fluconazole was 100 mg daily in the first phase of study and 200 mg daily in the second phase. RESULTS: Of 84 patients initially enrolled, 16 (19 percent) were found to have silent, persistent infection on the basis of cultures that became positive after entry into the study; 7 other patients were lost to follow-up shortly after entry. Of the remaining 61 patients, 10 of 27 assigned to placebo (37 percent) and 1 of 34 assigned to fluconazole (3 percent) had a recurrence of cryptococcal infection at any site (difference in risk, 34 percent; 95 percent confidence interval, 15 to 53). Of the 11 recurrent infections, 7 were detected in urine obtained after prostatic massage. There were four recurrent meningeal infections in the patients taking placebo, but none in those taking fluconazole (mean duration of follow-up, 164 days) (P = 0.03). In multivariate analyses, the best predictors of recurrence-free survival were fluconazole treatment (P = 0.02; relative hazard, 13.2), a lower serum cryptococcal-antigen titer (P = 0.05; relative hazard, 1.2), and more prolonged primary therapy with flucytosine (P = 0.09; relative hazard, 1.1). Survival and toxicity were similar in the two maintenance-treatment groups. CONCLUSIONS: In patients with AIDS, silent persistent infection is common after clinically successful treatment for cryptococcal meningitis. Maintenance therapy with fluconazole is highly effective in preventing recurrent cryptococcal infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

An overview of gene activity in the fat body of Drosophila gibberosa.

In the larval fat body of Drosophila gibberosa, polytene chromosome structure and activity exhibit cytological differences from chromosomes of midgut and salivary glands. These differences include long-persisting puffs, transient puffs and long-persisting band modulations. Some early ecdysteroid-induced puffs are present in all three organs but few late puffs are present in the fat body. Comparative studies reveal, therefore, that late larval-early pupal puffing is enhanced in salivary glands relative to gut, fat body and Malpighian tubules. After the fat body breaks up in the prepupa, the rate of programmed cell death and the corresponding slow decline of chromosomal activity also differ from cell to cell and from other organs.

Animals↗
PubMed1991

Prolonged survival following the inadvertent intrathecal administration of vincristine: clinical and electrophysiologic analyses.

A 23-year-old man with a lymphoblastic lymphoma accidentally received 2.0 mg of vincristine intrathecally instead of intravenously. Although he underwent immediate CSF drainage, symptoms of an ascending myeloencephalopathy developed at 48 h. This progressed to coma, initially with a diffusely slow EEG, which evolved into alpha coma. He also developed a left frontal focus of epileptiform activity. He was transferred to our institution 1 month later. His court-appointed guardian refused to allow discontinuation of supportive treatment; therefore, the evolution of the disorder can be followed for 12 months. Although alpha coma remained the predominant pattern, some EEG evolution did occur, with a progressive decrease in amplitude being most prominent. An increase in amplitude in the 10th month was accompanied by the return of some nystagmoid eye movements. The patient's lymphoma then recurred, and further treatment was not attempted. This tragic case, in which transient exposure to a microtubular poison produced severe CNS toxicity, allows some insights into the mechanisms of alpha coma.

Adult↗
PubMed1990

[Methylxanthines and benzodiazepine antagonism].

The mode of action of methylxanthines and benzodiazepines are not yet fully elucidated. Interaction with antagonizing effect occurs between these two preparations, probably with influence upon some of the same cellular systems. At least two types of benzodiazepine receptors in the cerebrum have been described. These are presumed to be placed in the neighbourhood of gamma-aminobutyric-acid (GABA) receptors and they probably modify the functions of these. In addition, influence on other transmitter systems in the CNS occurs with release of adenosine and reduction of the acetyl choline content. It has been demonstrated that methylxanthines are adenosine-blocking but they also release catecholamines from the suprarenal cortex and sympathetic nerve-ends both centrally and peripherally. In clinical practice, the antagonistic effect of employing methylxanthines in patients sedated with benzodiazepines has been demonstrated. Administration of 1-2 mg/kg of aminophyllin usually results in immediate effect and these patients woke up immediately after injection. When benzodiazepines and methylxanthines are administered simultaneously the total result will be difficult to predict.

Animals↗
PubMed1990

Hand handicap and rheumatoid arthritis in a fish-eating society (the Faroe Islands).

In the county of Klaksvik, the Faroes, a simple hand test was used for screening all inhabitants between the ages of 40 and 74 years. With its high sensitivity and specificity it revealed a diagnostic panorama entirely different from that seen in previous investigations in other nordic countries. In Klaksvik the prevalence of hand handicap was about 40%, which is due to the high incidence of osteoarthrosis. The prevalence of rheumatoid arthritis was 1.1%. The high functional capacity and the lower occurrence of rheumatic nodules and erosions found in the patients with rheumatoid arthritis as compared with previous studies suggest that the disease takes a milder course in Klaksvik. This should support the hypothesis that RA patients benefit from a diet rich in fish.

Adult↗
PubMed1990

In vivo generation and elimination of angiotensin in the rat.

1. Combined high performance liquid chromatography (HPLC) and radio-immunoassays were used to study the in vivo kinetics of the renin-angiotensin system in the rat. The HPLC-verified plasma concentrations of angiotensin I (AI) were 1.0 nmol/L (0.52-1.6) in anaesthetized normal and 4.2 nmol/L (2.5-7.0) in salt-depleted rats. The plasma concentrations of angiotensin II (AII) were 0.07 nmol/L (0.04-0.13) in anaesthetized normal and 1.0 (0.60-1.6) nmol/L in salt-depleted rats. 2. The fate of injected AI and AII passing through the vascular bed of the lungs was determined. Two-thirds of the injected AI was converted to AII and one-third was unchanged after a single passage through the lungs. Only trace amounts of angiotensin III (AIII), the only other metabolite, were demonstrated. 3. This verifies that the majority of AI is metabolized through AII. Injected AII disappeared from the circulation with formation of only trace amounts of AIII, the half-life being about 10 s. This corresponds to a calculated in vivo generation rate of AII of about 12 nmol/L per h in normal rats. It is in agreement with the AI generation rate (plasma renin activity) measured as 9.5 nmol/L per h in vitro.

Angiotensin I↗
PubMed1990

Cardiovascular and endocrine responses to haemorrhage in the pig.

Heart rate (HR), mean arterial pressure (MAP), indices of sympathetic and parasympathetic activity (plasma concentrations of adrenaline, noradrenaline and pancreatic polypeptide, PP), vasopressin (VP) and aldosterone (ALDO) were measured in six pigs during continuous bleeding resulting in hypovolaemic shock, from which five survived. Three stages of haemorrhage could be defined. Stage I. Resting MAP was 85 +/- 6 mmHg and increased to 96 +/- 5 mmHg with a blood loss of 275 (range 250-300) (10 (9-12)% of the estimated blood volume) concomitant with an increase in HR from 105 +/- 5 to 113 +/- 6 beats min-1 (P less than 0.05). Stage II. After a blood loss of 375 (300-500) ml (15 (13-16)%) MAP fell to 62 +/- 9 mmHg and HR to 95 +/- 5 beats min-1 (P less than 0.05). Stage III. A blood loss of 1113 (825-1450) ml (44 (30-52)%) resulted in a MAP of 50 +/- 4 mmHg and an increase in HR to 206 +/- 3 beats min-1 (P less than 0.05). Adrenaline increased from 0.3 +/- 0.1 to 0.8 +/- 0.3 (stage II) and 3.6 +/- 1.1 nmol l-1 (stage III) (P less than 0.05); noradrenaline from 0.4 +/- 0.1 to 1.5 +/- 0.4 (stage II) and 5.9 +/- 1.7 nmol l-1 (stage III) (P less than 0.05); PP from 6.2 +/- 1.6 to 13.3 +/- 2.3 (stage II) and 20.9 +/- 7.8 pmol l-1 (stage III) (P less than 0.05). VP changed only marginally, but ALDO increased from 496 +/- 54 to 623 +/- 76 pmol l-1 (stage III) (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1990

Effects of bovine 35 kDa FSH-suppressing protein on FSH and LH in rat pituitary cells in vitro: comparison with bovine 31 kDa inhibin.

The mode of action of a recently isolated gonadal protein, termed FSH-suppressing protein (FSP) or follistatin, on basal and gonadotrophin-releasing hormone (GnRH)-stimulated release of FSH and LH and on pituitary cell content of FSH and LH was examined in rat pituitary cell cultures and compared with the previously reported effects of inhibin. Pituitary cells were cultured for 3-9 days in the presence of graded doses of FSP and the basal release rates and changes in cell contents of FSH and LH determined during this period. FSP suppressed both the basal release rate and the cell content of FSH with median inhibitory concentrations (IC50) of 135 and 161 pmol/l respectively. The corresponding effects of FSP on LH basal release rate and LH cell content (IC50 = 200 pmol/l) were limited compared with the effects on FSH. The effect of FSP on GnRH-stimulated release of FSH and LH during 4 h was determined in cells which had been preincubated with FSP for 3 days, and the GnRH-stimulated release of FSH and LH analysed as a percentage of the respective gonadotrophin available for release. FSP antagonized GnRH action with dose-related increases in the GnRH median effective (stimulatory) concentrations for FSH and LH release (EC50 values = 56 and 400 pmol/l respectively) and a suppression in the maximum release of FSH and LH by excess GnRH (IC50 values = 142 and 150 pmol/l respectively). The effect of FSP on FSH cell content after 3 days in culture was insensitive to the neutralizing effects of an inhibin antiserum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Autologous epidural blood patch and post-lumbar puncture headache. A review of a 1-year period at a central hospital].

During a period of one year in which 609 spinal anaesthetics were performed, seven men and eight women complained of post lumbar puncture headache (PLPH). This form of headache was most frequently localized to the forehead and neck. The maximal intensities of the PLPH were assessed as "7-8" on a 10 cm visual analogous scale. All of these patients were treated with autologous epidural blood patch (AEBP). A mean volume of 17.8 ml autologous blood (range 10-20 ml) was injected into the epidural space. The injection was stopped as soon as low back pain occurred. The effect of AEBP occurred after a latent period with an average of two hours (range 0.5-6 hours). The effects of AEBP were indicated on a five-point ad hoc scale as "complete" or "nearly complete" in 13 out of 15 patients. Relapse occurred in one patient. No significant adverse effects were observed. AEBP is thus considered as a safe and effective form of treatment of PLPH.

Anesthesia, Spinal↗
PubMed1989

Injuries due to deliberate violence in areas of Denmark. I. The extent of violence.

As part of a transcultural investigation of violent behavior in Denmark and South America an analysis was made during a one year period of the incidents involving deliberate violence as registered at 3 Danish emergency wards, and at the Institute of Forensic Medicine in Copenhagen. In the three emergency wards a total of 1316 victims of deliberate violence were observed corresponding to a rate of about 3.3/1000 per year in a provincial/rural district, the catchment region of Holbaek County Hospital, 5.5/1000 per year in a mainly middle income area of the metropolis Copenhagen, the catchment region of Frederiksberg Hospital, and 7.6/1000 per year in a mainly low income area of Copenhagen, the catchment region of the Rigshospital. The highest risk, 28/1000 per year, was found for young men between 15 and 19 years of age living in the low income area of Copenhagen. The risk was low for people greater than or equal to 60 years of age in all three areas investigated, ranging from 0 (men) to 1.3/1000 per year (women). Skilled and unskilled workers were greatly over represented as victims of violence, considering their share of the background population. Seventy percent of the victims were men. At least 44% of the men and 32% of the women were alcohol intoxicated when arriving in the emergency ward. The incidents took place in restaurants or in the vicinity of restaurants for 30% of the male and 11% of female victims respectively, while 45% of the women had been subject to deliberate violence at home. The rate of fatal cases of deliberate violence in the Eastern part of Denmark, the catchment area for the Institute of Forensic Medicine in Copenhagen, was found to be 0.02/1000 per year. The risk of becoming a victim of deliberate violence has not increased during the last 4 years comparing with similar investigations from other parts of Denmark. However, the rate of homicide seems to have increased, and so has the severity of the injuries caused by deliberate violence. The pattern of deliberate violence appears to be associated with socio-economic and cultural factors, and to be closely linked with alcohol intoxication.

Adolescent↗
PubMed1989

Injuries due to deliberate violence in areas of Denmark. II. Victims of homicide in the Copenhagen area.

As part of a transcultural investigation of injuries due to deliberate violence in Denmark and South America, homicides in the Copenhagen area were studied for a 1-year period. Forty-five cases corresponding to a rate of approximately 2/10(5) per year were recorded. The rate seems to be increasing and the pattern changing with a higher frequency of stabbing and with an increasing frequency of high blood-alcohol concentrations in the victims. The highest number were killed at home. In the majority of cases the aggressor and the victim knew each other. A reduction in alcohol consumption is indicated as a possible preventive measure.

Adolescent↗
PubMed1989

Injuries due to deliberate violence in areas of Denmark. V. Violence against women and children. Copenhagen Study Group.

As part of an European-South American study of deliberate violence cases of violence against women greater than or equal to 15 years of age and violence against and among children under the age of 15 years were registered at 3 Danish emergency wards and at the Institute of Forensic Medicine in Copenhagen. 352 cases of violence against women and 46 cases of violence against children were registered in the three emergency wards corresponding to rates of about 1.6/1000 per year for women, 0.6/1000 per year for boys and 0.7/1000 per year for girls in a provincial/rural district, the catchment region of Holbaek County Hospital, 3.4/1000 per year for women, 2.8/1000 per year for boys and 0.6/1000 per year for girls in a mainly middle income area of the metropolis Copenhagen, the catchment region of Frederiksberg Hospital, and 4.0/1000 per year for women, 4.0/1000 per year for boys and 0.9/1000 per year for girls in a mainly low income area of Copenhagen, the catchment region of the Rigshospital. Nineteen live adult female victims and 17 dead adult female victims of violence were registered in the Institute of Forensic Medicine in Copenhagen, where also one was registered as a victim of homicide. Nearly half of the adult live female victims of violence had been injured at home while this was the case for approximately three fourth of the dead victims. In 35% of the live cases the husband was the aggressor and in 12% a former cohabitant. In 71% of the homicide cases the husband was the aggressor. The live women appeared to have fewer but more serious lesions than men. The pattern of deliberate violence against women appears to be associated with socio-economic and cultural factors. In cases with a preceding quarrel there is statistically a link to alcohol intoxication. In half of the cases of violence against children the aggressor was known to the victim, in 15% the aggressor was one of the parents, while 42% of the cases were violence among children. The pattern of violence according to sex, and the distribution and severity of lesions for 10-14 years old children showed resemblance to the situation for adults. The lesions were more serious in young infant victims, especially boys, than in adult victims.

Adolescent↗
PubMed1989

Solution of methodological problems in measurement of inactive renin in rat plasma using trypsin activation, and the effect of nephrectomy and sialo-adenectomy on inactive plasma renin.

Trypsin activation of rat plasma destroys angiotensinogen and generates a tetradecapeptide-like material, verified by high performance liquid chromatography, which interferes with the measurement of inactive renin. Using an assay based on removal of the material by a cation-exchange resin and the addition of exogenous angiotensinogen, the plasma concentration of inactive renin in intact conscious male rat was 0.48 GU/l (range 0.28-0.67 GU/l, n = 20). Inactive renin comprised about 70% of the total plasma renin. The level of inactive renin was unchanged 24 h after bilateral nephrectomy and 7 days after submandibular sialo-adenectomy. Bilateral nephrectomy of previously sialo-adenectomized rats decreased the level of inactive renin significantly. Our findings are in contrast to the marked increase, reported by several other investigators, in inactive plasma renin in rats following bilateral nephrectomy, and do not support the previously suggested, mainly extrarenal, origin of inactive plasma renin.

Animals↗