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Biomedical subjects

M Andersen

Publications and source records attributed to M Andersen.

At least 91 records · Page 5Linked to original sources
PubMed1991

Properties of some density-dependent integrodifference equation population models.

Integrodifference equations may be used as models of populations with discrete generations inhabiting continuous habitats. In this paper integrodifference equation models are formulated for annual plant populations without a seed bank; these models differ in the stage of the life cycle at which intraspecific competition acts to reduce vital rates. The models exhibit a sequence of period-doubling bifurcations leading to chaotic spatial and temporal behavior. The behavior of the models when modal dispersal distances are at the origin is compared with their behavior when these distances are displaced away from the origin. The models are capable of predicting stable, cyclical, and chaotic asymptotic behavior. They also predict that the variance of dispersal distances is an important indicator of the colonizing ability of a species.

Animals↗
PubMed1991

The mental health of women 6 months after they give birth to an unwanted baby: a longitudinal study.

This study reports a longitudinal prospective study of the impact of an unwanted pregnancy on the mental health of the mother. Data are derived from a Brisbane, Australian sample of 8556 mothers who were enrolled at their first clinic visit (mean gestation 18 weeks) and then interviewed again some 3-5 days after the birth and when the baby was 6 months of age. Standard scales of mental health were administered on each of these occasions and mothers whose babies were unwanted were compared with the rest of the sample. The results indicate that mothers of unwanted children have somewhat higher rates of anxiety and depression than the comparison group, but that the magnitude of the mental health differences between the two groups: (a) diminishes over the period of the follow-up, (b) may be partly attributable to the prior poor mental health of women giving birth to an unplanned and unwanted baby, (c) is such that relatively few women who give birth to an unwanted baby experience mental health problems. The paper considers the implications of these results for health planners, notes the absence of contrary data and the need to acknowledge that these results may reflect situational factors which are characteristic of but not necessarily limited to Brisbane.

Adolescent↗
PubMed1991

Adverse reactions to H2-receptor antagonists in Denmark before and after transfer of cimetidine and ranitidine to over-the-counter status.

The H2-receptor antagonists cimetidine and ranitidine were transferred from prescription only to over-the-counter (OTC) status in Denmark on March 27, 1989. Reports to the Danish Committee on Adverse Drug Reactions, a voluntary reporting system, have been evaluated to detect possible changes in frequency and pattern of adverse drug reactions (ADRs) caused by the altered delivery status. From the introduction of cimetidine in 1977 and until March 31, 1990, the Committee received 494 reports of 612 suspected adverse reactions to anti-ulcer drugs. The H2-receptor antagonists (mainly cimetidine and ranitidine) were responsible for 548 (90%) of the ADRs. The study, which presents experience with these drugs from more than a decade and a total consumption corresponding to 65 million treatment days, confirms their excellent safety record. Serious reactions were rare, and when they occurred, reversible. During the first year with cimetidine and ranitidine available OTC no changes were seen in reporting frequency or ADR pattern which could be ascribed to OTC transfer. Only one ADR report concerning OTC cimetidine was received. This may be caused by several factors: the safety of these drugs, the fact that only very little was actually sold OTC, and a relatively low sensitivity of the voluntary reporting system.

Adverse Drug Reaction Reporting Systems↗
PubMed1991

Postphlebitic syndrome and general surgery: an epidemiologic investigation.

Of a random sample comprising 4581 subjects from The Copenhagen County, 3608 (79%) attended an interview and a general health examination. The subjects were defined as suffering from subjective postphlebitic syndrome if they claimed of lower extremity pain or cramps at rest and from objective postphlebitic syndrome if varicose veins, edema, lower extremity ulcers, or skin changes were present. By means of logistic regression analysis, subjective postphlebitic syndrome was found independently associated with previous thromboembolism, obesity, increasing age, female sex, hormonal therapy, varicose veins, and previous major abdominal surgery. Objective postphlebitic syndrome was associated with previous thromboembolism, obesity, former birthgiving, and high social status. The findings support the view that subclinical deep venous thrombosis in connection with previous surgery may give rise to symptoms in the lower extremities.

Adult↗
PubMed1991

Late complications of asymptomatic deep venous thrombosis.

Forty-one patients who had all participated in studies about prophylaxis of postoperative deep venous thrombosis (DVT) were investigated 5-8 years after operation. Twenty-five had had asymptomatic DVT detected by 125I-fibrinogen uptake test or 99mTc plasmin scintigraphy and verified by phlebography, four of which were bilateral. They received anticoagulant treatment for three months. Sixteen patients had normal screening tests. At the follow up legs in which DVT had previously been diagnosed were compared with normal legs in patients who did not have DVT. There was no significant difference in subjective symptoms between the two groups of legs, although there were more complaints of oedema and restlessness in legs in which DVT had been diagnosed and varicose veins were more common. When the incidence of varicose veins before the operation and at the follow up was compared, more patients who had had a DVT had developed varicose veins. Blood volume and venous refilling time were measured by strain gauge plethysmography, and were significantly lower in those with a history of DVT than in normal legs. The results indicate impaired venous function in patients who previously had had asymptomatic DVT treated with anticoagulants.

Aged↗
PubMed1990

[The occurrence of late thromboembolic complications after elective abdominal surgery].

Forty-five consecutive patients who were submitted to elective major abdominal surgical interventions under optimal thromboembolic prophylaxis participated in an investigation as regards the occurrence of late thromboembolic complications. The patients were followed postoperatively with 125I-fibrinogen scanning every second day for a week or until discharge from hospital. If deep venous thrombosis was suspected, intravenous phlebography was carried out. Thirty-five patients completed the investigation. None of the patients developed deep venous thrombosis during thromboembolic prophylactic treatment. In two patients (6%) (95% confidence limits 1-19%), deep venous thrombosis was demonstrated after conclusion of prophylaxis, 13 and 28 days postoperatively, respectively. It is concluded that despite optimal thrombosis prophylaxis, late thromboembolic complications may occur. Prospective investigations are required to elucidate the clinical significance of late thromboembolic complications and to illustrate the value of prolonged thrombosis prophylaxis.

Adult↗
PubMed1990

The developmental morphology of a "periosteal" ligament insertion: growth and maturation of the tibial insertion of the rabbit medial collateral ligament.

The structural properties of ligament insertions change dramatically during growth and maturation, but little is known about their developmental anatomy. This study describes and quantifies changes in the gross and microscopic anatomy of the tibial insertion of the rabbit medial collateral ligament (MCL) during development and at skeletal maturity. Eighty animals were used for growth and descriptive studies. From this group, 27 animals, ranging in age from 1 to 24 months, were injected with fluorescent bone markers and their tibial insertions were processed undecalcified for histology. Sections were examined by polarized light and fluorescence microscopy to identify matrix and cells and to quantify mineral formation. Results showed that animals achieved histological skeletal maturity between 9 and 12 months of age. Body weights were a poor index of skeletal maturity. The tibial insertion was composed of five tissue layers, which changed proportions during growth and maturation. In immature animals, MCL fibers entered the periosteum; in older animals, MCL fibers were cemented to the tibia by advancing mineral. The tibial attachment of the MCL was thus transferred from the periosteum to the cortex during growth, suggesting that the term "periosteal insertion" is imprecise in adults. The hypothesis is put forward that these structural changes account for the reported increase in tensile failure of this insertion near skeletal maturity.

Aging↗
PubMed1990

Second-line chemotherapy in small cell lung cancer.

The literature on second-line chemotherapy in small cell lung cancer (SCLC) for the period 1979-1989 is reviewed. The reports consisted mainly of Phase II type studies and comprised a total of 987 patients with relatively few patients per study. The information was frequently incomplete with regard to duration of response on first-line chemotherapy, length of any drug-free interval and duration of response on second-line chemotherapy. The overall second-line response rate was 30%, but only 5% were complete responses (CR). The response rates obtained by the combination of cisplatinum (P) and VP-16 (E) or reinduction therapy were 45% and 64% (medians), respectively. These rates were superior to regimens consisting of supposedly non-cross-resistant agents. With P and E not given in combination, the response rates were less than 20%.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Effect of major surgery on absorption rate of NPH insulin injected s.c.

The absorption rate of NPH insulin injected s.c. was evaluated before operation and on the day of surgery by continuous measurements of residual radioactivity of 125I-labelled insulin in 10 patients undergoing major abdominal surgery. The results show that major surgery has no effect on rate of absorption of intermediate acting insulin.

Abdomen↗
PubMed1989

[Electrocoagulation as radical treatment of anorectal cancer].

During a 17 year period, 19 patients with ano-rectal cancers were treated radically by electrocoagulation. Ten patients (52%) were treated successfully with electrocoagulation as the only treatment. The method is recommended as an alternative to radical surgery in carefully selected patients. The patients should be followed up at regular intervals. No serious complications occurred.

Aged↗
PubMed1989

The arterial supply of the clavicle.

This report based on delineation of the arterial system with 3 component plastic material on 10 human cadavers describes the arterial supply to the clavicle. The study was performed in 2 parts. One part, which showed the total arterial supply to the clavicle and one part with selective injections of the relevant arteries, with the intention of finding a central nutrient arterial supply to the clavicle. Three arteries were found to supply the clavicle: the suprascapular a.; the thoracoacromial a.; and the internal thoracic (mammary) a. The main supply was primarily periosteal. No nutrient artery was found.

Aged↗
PubMed1989

The effect of general anaesthesia on the haemodynamic events during laparoscopy with CO2-insufflation.

Sixteen women were studied during elective diagnostic laparoscopy with CO2-insufflation to an intraabdominal pressure (IAP) of 2 kPa and Trendelenburg tilt to 30 degrees. They were allocated to either a halothane (Group I) or a balanced (Group II) anaesthesia with relaxation and controlled ventilation. Heart rate (HR), arterial pressure, stroke volume, CO2-elimination, end-tidal CO2 vol.% and total respiratory compliance (TRC) were the parameters measured, and mean arterial pressure (MAP), total peripheral resistance (TPR), stroke index (SI) and cardiac index (CI) were calculated. At maximum haemodynamic strain, SI and CI were on average reduced by 42% in both groups, without significant changes in HR and MAP. TPR increased by 50% in Group I and 100% in Group II. The reduction in SI was related to the changes in TRC. A small increment in CO2-elimination after CO2-insufflation was most pronounced in Group II. SI and CI did not reach the pre-insufflation values after return to the horizontal position and CO2-exsufflation. The haemodynamic differences between the two groups were small compared to the effects of the laparoscopy procedures.

Adolescent↗