Biomedical subjects

H Christensen

Publications and source records attributed to H Christensen.

At least 163 records · Page 9Linked to original sources

PubMed1996

[Systemic lupus erythematosus during pregnancy].

Systemic lupus erythematosus (SLE) is a connective tissue disease most commonly affecting women of a fertile age. It is recommended that pregnancy is planned during periods with remission or low activity of he disease because it seems that SLE is more likely to be exacerbated by pregnancy when the disease is active at the time of conception. Presence of circulating anti-phospholipid antibodies is associated with a poor prognostic outcome for the foetus and increases the risk of complications related to pregnancy.

Adult↗

PubMed1996

Collagen deposition and mechanical strength of colon anastomoses and skin incisional wounds of rats.

The mechanical strength development of healing wounds depends on the formation of collagen fibrils bridging the wound cleft. A considerable deposition, degradation, and remodeling of these fibrils takes place influencing the mechanical strength of the healing wounds. A method for studies of wound collagen metabolism in vivo is delineated, enabling determination of collagen deposition per hour in rat colon anastomoses and skin incisional wounds. Labeled proline was incorporated into wound collagen with a flooding dose of unlabeled proline, reducing errors introduced by proline recycling and proline de novo synthesis. The mechanical strength was determined by a materials testing machine. In both colon anastomoses and skin wounds a substantial increase in collagen deposition was observed at Day 2, reached a maximum at Day 6, and was still relatively high at Day 12 during the remodeling of collagen fibers in the wound cleft. The collagen deposition in colon anastomoses at Day 6, however, was 10-fold higher compared with that of the skin incisional wounds. The time course of the collagen deposition was much alike in colon anastomoses and skin incisional wounds reaching a maximum at Day 6. The mechanical strength of these two rather different types of wounds was increased correspondingly and to the same level during the 1st week of healing. The measurements of collagen deposition, collagen content, and biomechanical strength indicated a substantial turnover of newly synthesized and deposited collagen during the early phases of wound healing. On the basis of this, it seems obvious that even small disturbances to the balance between collagen synthesis, deposition, collagen cross-linking, and collagen degradation/remodeling may result in defective wound healing.

Anastomosis, Surgical↗

PubMed1996

Effect of insulin-like growth factor I (IGF-I) administration on the healing of colonic anastomoses in rats.

BACKGROUND: The gastrointestinal tract is highly responsive to the tropic effect of growth hormone (GH). GH stimulates the healing of colonic anastomoses either directly or through insulin-like growth factor I (IGF-I) since specific GH receptor as well as IGF-I receptor have been demonstrated in colon. AIM: To determine whether exogenous treatment with IGF-I could stimulate the healing of left colonic anastomoses in rats. METHODS: After colonic anastomotic operations adult rats were randomised to treatment with either IGF-I (500 mu g per day) or vehicle (controls). Anastomotic breaking strength and collagen deposition were determined at day after surgery. RESULTS: IGF-I treatment increased the anastomotic collagen content by 23% compared with controls. This resulted in a lower extensibility of the anastomosis (P < 0.05), whereas the anastomotic breaking strength did not differ between groups. The treatment resulted in a 3 fold increase in serum IGF-I of IGF-I treated rats, compared to controls. The postoperative body weight increased by 5% in the IGF-I rats from day 0 to day 3, while the control group had a weight loss of 2% in the same period (P < 0.001). CONCLUSION: Treatment of colon-operated rats with IGF-I increased the postoperative body weight and stimulates the collagen deposition of left colonic anastomoses, whereas the anastomotic strength may be unaffected by IGF-I treatment.

Anastomosis, Surgical↗

PubMed1996

Human erythropoietin response to hypocapnic hypoxia, normocapnic hypoxia, and hypocapnic normoxia.

This study investigated the human erythropoietin (EPO) response to short-term hypocapnic hypoxia, its relationship to a normoxic or hypoxic increase of the haemoglobin oxygen affinity, and its suppression by the addition of CO2 to the hypoxic gas. On separate days, eight healthy male subjects were exposed to 2 h each of hypocapnic hypoxia, normocapnic hypoxia, hypocapnic normoxia, and normal breathing of room air (control experiment). During the control experiment, serum-EPO showed significant variations (ANOVA P = 0.047) with a 15% increase in mean values. The serum-EPO measured in the other experiments were corrected for these spontaneous variations in each individual. At 2 h after ending hypocapnic hypoxia (10% O2 in nitrogen), mean serum-EPO increased by 28% [baseline 8.00 (SEM 0.84) U.l-1, post-hypoxia 10.24 (SEM 0.95) U.l-1, P = 0.005]. Normocapnic hypoxia was produced by the addition of CO2 (10% Co2 with 10% O2) to the hypoxic gas mixture. This elicited an increased ventilation, unaltered arterial pH and haemoglobin oxygen affinity, a lower degree of hypoxia than during hypocapnic hypoxia, and no significant changes in serum-EPO (ANOVA P > 0.05). Hypocapnic normoxia, produced by hyperventilation of room air, elicited a normoxic increase in the haemoglobin oxygen affinity without changing serum-EPO. Among the measured blood gas and acid-base parameters, only the partial pressures of oxygen in arterial blood during hypocapnic hypoxia were related to the peak values of serum-EPO (r = -0.81, P = 0.01). The present human EPO responses to hypoxia were lower than those which have previously been reported in rodents and humans. In contrast with the earlier rodent studies, it was found that human EPO production could not be triggered by short-term increases in pH and haemoglobin oxygen affinity per se, and the human EPO response to hypoxia could be suppressed by concomitant normocapnia without acidosis.

Adult↗

PubMed1996

Hazard identification in swine slaughter with respect to foodborne bacteria.

Swine slaughter is an open process with many opportunities for the contamination of the pork carcass with potentially pathogenic bacteria; however, it does not contain any point where hazards are completely eliminated. Data on the prevalence of various pathogenic bacteria (Aeromonas hydrophila, Campylobacter coli/jejuni, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Yersinia enterocolitica) in pigs, their growth and survival characteristics and ability to become established on the slaughter line are presented. The presentation covers the processing steps from lairage to chilling and is based on swine slaughter practices in Denmark, Norway and Sweden. The major contamination points during swine slaughter are pig-related, such as faecal and pharyngeal, and environmental. HACCP (Hazard Analysis Critical Control Point) and GMP (Good Manufacturing Practice) in swine slaughter must be focused on limiting this spread. The pathogenic bacteria show differences in their general mechanism of distribution. The major contamination source of Campylobacter spp., Salmonella spp. and Y. enterocolitica is the pig, and the contamination of carcasses with these bacteria may be limited, provided that only strict slaughtering procedures are used. Other organisms such as Aeromonas spp., L. moncytogenes/Listeria spp. and S. aureus can be endemic in the processing environment. Since endemic bacteria can be controlled by proper cleaning and disinfection, these organisms are useful as indicators for the success of GMP rules. The following affiliation to CPs or CCPs made for specific steps during slaughter and dressing may serve as a guidance: (i) lairage (CP), (ii) killing (CP), (iii) scalding (CP), (iv) dehairing (CP), (v) singeing/flaming (CP), (vi) polishing (CP), (vii) circumanal incision and removal of the intestines (CCP), (viii) excision of the tongue, pharynx, and in particular the tonsils (CCP), (ix) splitting (CP), (x) post mortem inspection procedures (CCP) and (xi) deboning of the head (CCP).

Abattoirs↗

PubMed1996

Activity levels and cognitive functioning in an elderly community sample.

The influence of self-reported and informant-reported activity levels on Crystallized Intelligence, Fluid Intelligence, Memory and the Mini-Mental State Examination was investigated in a sample of 858 community-dwelling elderly subjects. Both self-reported and informant-reported activity levels explained variance beyond that accounted for by sex, sensory functioning, activities of daily living, medical conditions, current health problems and education. Age accounted for additional variance once activity and the other contextual variables were entered. Interaction effects indicated that inactivity was associated with poorer performance on fluid intelligence in older rather than younger elderly subjects and that inactivity was predictive of poor crystallized intelligence at younger ages. Higher informant-rated activity levels moderated the effects of education, so that higher activity offset effects associated with low education on memory tasks. The mount of variance explained by activity levels was modest.

Activities of Daily Living↗

PubMed1996

Informant ratings of cognitive decline of elderly people: relationship to longitudinal change on cognitive tests

Formal assessment of cognitive decline with cognitive tests can be difficult, requiring either two measurement points or a comparison of 'hold' with 'don't hold' tests. Informant-based assessment provides an alternative approach because informants can adopt a longitudinal perspective and directly rate cognitive change. A study was carried out to assess the validity of informant ratings collected by means of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). A community sample of 500 subjects aged 74 or over underwent four cognitive tests on two occasions 3&half; years apart. On the second occasion, informants filled out the IQCODE. Subjects rated as having moderate or severe decline were found to have greater change on the cognitive tests. These findings support the validity of informant ratings of cognitive decline.

Journal Article↗

PubMed1996

Informant ratings of cognitive decline of elderly people: relationship to longitudinal change on cognitive tests.

Formal assessment of cognitive decline with cognitive tests can be difficult, requiring either two measurement points or a comparison of 'hold' with 'don't hold' tests. Informant-based assessment provides an alternative approach because informants can adopt a longitudinal perspective and directly rate cognitive change. A study was carried out to assess the validity of informant ratings collected by means of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). A community sample of 500 subjects aged 74 or over underwent four cognitive tests on two occasions 3 1/2 years apart. On the second occasion, informants filled out the IQCODE. Subjects rated as having moderate or severe decline were found to have greater change on the cognitive tests. These findings support the validity of informant ratings of cognitive decline.

Aged↗

PubMed1996

Motor control and kinetics during low level concentric and eccentric contractions in man.

Motor unit (MU) recruitment patterns were studied in 6 female subjects during dynamic contractions at relative workloads corresponding to 10% maximum voluntary contraction. The contractions consisted of a 20 degree elbow flexion (concentric contraction) and extension (eccentric contraction) and MU action potential trains were recorded from the brachial biceps muscle. The mean angular velocity of the dynamic contractions was 10 degrees/s, during which a total of 119 MUs were identified. Additionally, a few contractions were studied at 20 degrees/s during which 30 MUs were identified, and 9 MUs during the 40 degrees/s contraction. About 60% of the identified MUs were active during the concentric as well as the eccentric phase for each of the velocities. Mean firing rate decreased significantly when the contraction changed from concentric to eccentric, whereas the number and properties of identified active MUs were similar. This emphasizes firing rate modulation as important during low level dynamic contractions rather than selective recruitment of different types of MUs in the concentric versus the eccentric phase. Similar kinetic demands occur frequently in occupational tasks, especially during monotonous work. The present data indicate that only a limited pool of MUs are being recruited during such tasks. Extensive recruitment of these MUs may cause fatigue and start a potentially vicious circle leading to work-related muscle disorders.

Action Potentials↗

PubMed1995

Apolipoprotein E allele epsilon 4, dementia, and cognitive decline in a population sample.

From clinically based series it has been proposed that, in homozygotes for the apolipoprotein E epsilon 4 (apoE epsilon 4) allele, Alzheimer's disease is almost inevitable by the age of 80. A population sample of persons aged 70 years and over was interviewed in 1990-91 to ascertain the presence of dementia or cognitive impairment. The sample was reinterviewed in 1994, when the apoE genotype was also determined. Prevalence data for the 638 persons who completed the second examination revealed a linear association between having an apoE epsilon 4 allele and both dementia and cognitive impairment (for heterozygotes, odds ratio for dementia 1.89, 95% confidence interval 1.04-3.44 and for homozygotes OR 3.58, 95% CI 1.08-11.82; both adjusted for age). However, even in subjects homozygous for epsilon 4 the estimated prevalence of dementia by age 90 was only about 50%. Persons with one or two epsilon 4 alleles were more likely to have a family history of dementia than those with none. This study confirms in a population sample that the epsilon 4 allele is a risk factor for dementia, but refutes the suggestion that homozygosity for the epsilon 4 allele is sufficient for the development of Alzheimer's disease: persons with either one or two epsilon 4 alleles may reach late old age without cognitive impairment.

Aged↗

PubMed1995

Insomnia in the elderly: its prevalence and correlates in the general population.

OBJECTIVE: To estimate the prevalence of persistent insomnia and its correlates in samples of people living in the community and in institutional settings. METHODS: Respondents were interviewed in their place of residence by trained interviewers using the Canberra Interview for the Elderly, a structured psychiatric examination. RESULTS: Information about sleeping habits was obtained from 874 community and 59 institutional residents. Insomnia was persistent in 16% of the community-dwelling population and 12% of the institutional residents, with 15% and 40%, respectively, regularly taking a hypnotic. Of those without insomnia, 10% in the community but over a third in institutions were using a hypnotic. Insomnia was associated with depression, pain and poor physical health. CONCLUSIONS: Persistent insomnia in the elderly, as in other age groups, is strongly associated with depressed mood, as well as with physical disease. Because of this, insomnia should not be dismissed as a normal part of ageing, and therefore ignored as a significant symptom. Continued surveillance is needed in general practice, geriatric services and nursing homes of the routine use of hypnotics by the elderly.

Activities of Daily Living↗

PubMed1995

Collagen structural organization of healing colonic anastomoses and the effect of growth hormone treatment.

PURPOSE: This experimental study was designed to investigate the collagen fibrils of colonic anastomoses in rats and to compare normal healing with rats treated with biosynthetic growth hormone (bGH). METHODS: The healing zone of left colonic anastomoses was studied at days 2, 4, and 6 after surgery by means of scanning electron microscopy. RESULTS: After four days of healing a normal anastomosis was filled with loosely packed and unorganized collagen fibrils, which were organized into collagen fibers after six days. Compared with normal anastomoses, rats treated with bGH showed a more organized healing, characterized by a dense structure of a new-formed collagen framework of fibrils and immature collagen fibers after six days. CONCLUSIONS: Healing colonic anastomoses are characterized by new-formed collagen fibrils at postoperative day 4, and bGH seems to stimulate structural organization of the anastomotic collagen fibrils into fibers.

Anastomosis, Surgical↗

PubMed1995

ICD-10 mild cognitive disorder: epidemiological evidence on its validity.

Criteria for the diagnosis of ICD-10 Mild Cognitive Disorder (MCD) were applied to a sample of 897 community dwelling elderly participants. Criterion A (the presence of a physical disorder) was met by 44%, Criterion B (report of a cognitive disorder) by 17%, Criterion C (an abnormality in quantified cognitive assessments) by 60%, and Criterion D (exclusion on basis of dementia and other conditions) by 74%. A total of 36 cases (4%) met all four criteria. Correlations between Criteria A and B, and B and C were weak (r = 0.18), and the correlation between Criteria A and C was almost zero (r = 0.02). This suggests that no syndrome exists. Membership of MCD was predicted by a report that memory or intelligence interfered with daily life but not by performance on cognitive tests or by a report of physical illness. Cases of MCD had higher anxiety, depression and neuroticism scores than normal elderly, but did not differ substantially on tests of cognitive functioning. These findings call into question the validity of the ICD-10 diagnosis of MCD.

Activities of Daily Living↗

PubMed1995

The Psychogeriatric Assessment Scales: a multi-dimensional alternative to categorical diagnoses of dementia and depression in the elderly.

The Psychogeriatric Assessment Scales (PAS) provide an assessment of the clinical changes seen in dementia and depression. Principal components analysis and latent trait analysis were used to develop a set of scales to summarize these clinical changes. There are three scales derived from an interview with the subject (Cognitive Impairment, Depression, Stroke) and three from an interview with an informant (Cognitive Decline, Behaviour Change, Stroke). Results are reported on the reliability and validity of these scales using data from clinical samples in Sydney and Geneva and a population sample from Canberra. The scales were found to have excellent validity when judged against clinical diagnoses of dementia and depression and could distinguish Alzheimer's from vascular dementia. Cut-off points were developed to indicate correspondence between scale scores and clinical diagnoses. Percentile rank norms were developed from the Canberra population sample. The PAS is easy to administer and score and can be used by lay interviewers after training. It is intended for application both in research and in services for the elderly.

Activities of Daily Living↗

PubMed1995

A national cross-sectional study in the Danish wood and furniture industry on working postures and manual materials handling.

Musculoskeletal disorders constitute a major problem in the wood and furniture industry and identification of risk factors is needed urgently. Therefore, exposures to different work tasks and variation in the job were recorded based on an observation survey in combination with an interview among 281 employees working in wood working and painting departments. A questionnaire survey confirmed high frequencies of symptoms from the musculoskeletal system: The one-year prevalence of symptoms from the low back was 42% and symptoms from the neck/shoulder was 40%. The exposure was evaluated based on: (1) classification of work tasks, (2) work cycle time, (3) manual materials handling, (4) working postures, and (5) variation in the job. Among the employees 47% performed feeding or clearing of machines, 35% performed wood working or painting materials, and 18% performed various other operations. Among the employees 20% had no variation in their job while 44% had little variation. Manual materials handling of 375 different burdens was observed, which most often occurred during feeding or clearing of machines. The weight of burdens lifted was 0.5-87.0 kg, where 2% had a weight of more than 50 kg. Among the lifting conditions 30% were evaluated as implying a risk of injury. An additional risk factor was the high total tonnage lifted per day, which was estimated to range from 132 kg to 58,800 kg. Working postures implied a risk of injury due to prolonged forward and lateral flexions of the neck, which was seen most frequently during wood working or painting materials. These data substantiate the finding that work tasks mainly during feeding or clearing of machines imply a risk of injury to the low back and a risk of injury to the neck and shoulder area mainly during wood working or painting materials. Optimal strategies for job redesign may be worked out by using these data in order to prevent occupational musculoskeletal disorders.

Adolescent↗

PubMed1995

Factors associated with the wish to die in elderly people.

This study aimed to determine the prevalence of the wish to die in elderly people and investigate the factors associated with it, in particular, whether factors other than depression contribute to the wish to die. Data were obtained from an Australian epidemiological survey of people aged 70 or more. Survey participants were asked whether, in the last two weeks, they had felt that they wanted to die and, if so, if they had had such thoughts repeatedly. Three classes of possible risk factors were investigated: sociodemographic factors (age, sex, marital status), mental health (depression, cognitive impairment), and physical health (poor self-rated health, disability, pain, sensory impairment, and living in a nursing home or hostel). Only 21 of 923 elderly persons reported repeatedly having had a wish to die during the previous two weeks. Although the wish to die was associated with depression, there were several other factors also associated with it independently of depression: not being married, poor self-rated health, disability, pain, hearing impairment, visual impairment, living in a nursing home or hostel. A small minority expressed the wish to die but had a normal mood state. It was concluded that the wish to die is associated with several factors in addition to depression and may be present in individuals with few depressive symptoms. There is a need to investigate whether factors associated with the wish to die are treatable and whether this can restore the desire to live.

Aged↗

PubMed1995

Detection of Yersinia enterocolitica O:3 in faecal samples and tonsil swabs from pigs using IMS and PCR.

Dilutions of faecal samples spiked with Yersinia enterocolitica O:3 were analysed using immunomagnetic separation (IMS) followed by PCR. In 10% faecal dilutions with added Y. enterocolitica cells, the limit of detection was 200 cells g-1 faeces. Faecal samples from 38 pigs were analysed by IMS-PCR in parallel with detection and quantification of Y. enterocolitica O:3 using cold pre-enrichment culturing. Of the 15 culture-positive samples, only two were detected with IMS-PCR. These two samples contained 40-400 Y. enterocolitica O:3 cells g-1 faeces; the highest level found in the investigation. This indicated that the low sensitivity of IMS-PCR was due to low amounts of cells in the faecal samples. Swab samples from 195 pig tonsils, taken on a slaughterline were examined using IMS-PCR and culture detection. Of 164 culture-positive samples, 60 were positive with IMS-PCR. In addition, IMS-PCR was positive for three culture-negative samples. Forty-five of the samples were further examined by IMS-PCR after 7-10 d of cold pre-enrichment. All 31 culture-positive samples as well as five culture-negative samples were detected by IMS-PCR. From these data it can be concluded that IMS-PCR can be used to detect Y. enterocolitica O:3 cells after pre-enrichment, but direct detection needs further optimization of the sample preparation procedures.

Animals↗

PubMed1995

Impaired wound healing but unaltered colonic healing with increasing age: an experimental study in rats.

Age-related differences in the healing of left colonic anastomoses and abdominal incisional wounds were compared between young and old rats. Immediately after surgery the anastomotic strength (suture-binding capacity) was 67% higher in old rats corresponding to a 107% higher collagen content per unit length of left colon compared to young rats. After 2 and 4 days of healing there was no difference in the breaking strength of the anastomoses between young and old rats, although the increase in collagen content of the anastomosed segment was 100% in the young rats and only 35% in the old rats from day 2 to day 4. The healing of the abdominal incisional wounds was, however, impaired in old rats compared to young rats, since the tensile strength and the energy absorption on the 4th postoperative day was 67 and 57% lower, respectively. In conclusion, old rats have impaired skin healing, whereas colonic healing is not affected by age.

Aging↗