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Biomedical subjects

C Christiansen

Publications and source records attributed to C Christiansen.

At least 217 records · Page 12Linked to original sources
PubMed1994

Immunoassay for quantifying type I collagen degradation products in urine evaluated.

An enzyme-linked immunosorbent assay (ELISA) for measuring type I collagen degradation products in urine < 3 h was evaluated. The measuring range was 0.5-10.5 mg/L with a detection limit of 0.2 mg/L. Within-run and total CVs were 5.3% and 6.6%, respectively. Analytical recovery averaged 100%. The mean (+/- SD) concentrations in urine samples from a healthy premenopausal population (n = 102) were 250 +/- 110 mg/mol creatinine (Cr). A group of healthy postmenopausal women (n = 410) gave a mean value of 416 +/- 189 mg/mol Cr. Values obtained in the ELISA correlated well (r = 0.83) to HPLC values for the established bone resorption marker deoxypyridinoline (n = 214), slightly better than the correlation to hydroxyproline measurements (r = 0.78, n = 421). We conclude that the assay described here presents a useful tool for further elucidating the importance of type I collagen degradation products in urine.

Amino Acid Sequence↗
PubMed1994

The different routes of administration and the effect of hormone replacement therapy on osteoporosis.

OBJECTIVE: To review osteoporosis, a disease characterized by low bone mass, microarchitectural deterioration of bone tissue leading to increased bone fragility and a consequent increase in fracture risk. The disorder has become a major health problem in the West, where increased life expectancy has placed new emphasis on disorders related to aging. DESIGN: Review of selected literature. MAIN OUTCOME MEASURES: Bone mass increases rapidly in growing children and adolescents, reaching a peak in adults in their 20s and 30s. After 35 to 45 years of age, bone mass begins to decline slowly. Men lose bone mass at approximately the same rate over their lifetime; in women, however, the rate of bone loss increases dramatically after their menopause, whether it is natural or surgical. It is also important to note that bone mass in women below the age of 50 is just two thirds of that found in men. These two factors--the low initial adult bone mass and the more rapid bone loss--combine to produce a high incidence of osteoporosis in elderly women. Significant morbidity and mortality are attributed to osteoporosis-related fractures, underlining the importance of new therapeutic and preventive modalities being evaluated and applied in high-risk populations. In adult women before the onset of menopause, rates of bone formation and bone resorption are approximately equal; calcium balance is maintained, and no loss of bone mass occurs. But after menopause, although both bone formation and bone resorption rates increase, the rate of bone resorption increase more rapidly, resulting in calcium imbalance and a net loss of bone. The first goal of therapy for osteoporosis is thus the restoration of bone resorption and bone formation to premenopausal levels. Optimally, bone formation may be maintained at a slightly higher level than that of bone resorption, producing a positive calcium balance.

Bone Density↗
PubMed1994

Physical and biochemical characterization of Albunex, a new ultrasound contrast agent consisting of air-filled albumin microspheres suspended in a solution of human albumin.

Albunex is a new ultrasound contrast agent for medical imaging. The product consists of air-filled albumin microspheres suspended in a solution of 5% (w/v) human albumin. The suspension is sterile, non-pyrogenic and isotonic, with a pH of 7.0 and a viscosity of 1.4 relative to water. The contrast effect is caused by the air-filled microspheres, which range in diameter from 1 to 15 microns, with less than 5% being larger than 10 microns. The product contains a total of about 7 x 10(8) microspheres/ml of suspension. The number concentration of microspheres with diameters between 4 and 10 microns is about 2 x 10(8)/ml. The latter microsphere fraction is assumed to give the main contribution to the ultrasound signal in the left ventricle of the heart after intravenous injection. The air-filled microspheres are prepared by sonication of a heated solution of 5% (w/v) human albumin. During the sonication process, microbubbles of air are formed which become encapsulated in a thin shell of aggregated albumin about 15 nm in thickness. Due to the stabilizing effect of the albumin shell, the air-filled microsphere suspension is stable for at least 2 years when stored refrigerated. The microsphere protein represents about 1.5% of the total protein in the suspension. The remaining protein is soluble albumin molecules which behave like the albumin molecules in the starting material when analysed by a number of biochemical techniques.

Albumins↗
PubMed1994

General versus regional anaesthesia and platelet aggregation in minor surgery.

In order to evaluate the impact of minor surgery on platelet aggregability and the effect of anaesthesia on this parameter, we allocated 14 otherwise healthy men for inguinal herniotomy to either general anaesthesia (n = 7) or lumbar epidural anaesthesia (n = 7). Platelet aggregation threshold to adenosine diphosphate (ADP-threshold) was measured before and after anaesthesia, prior to surgery, at the end of surgery and during the following hours as well as on the first post-operative morning. General anaesthesia did not affect ADP-threshold while epidural analgesia itself induced a significant increase. During and soon after surgery the ADP-threshold increased in those receiving general anaesthesia while in those receiving epidural analgesia the ADP-threshold returned to pre-operative levels. On the first post-operative morning both groups showed a significantly lower ADP-threshold as compared to the pre-operative level. Surgery induced an increase in 3'5' cyclic-adenosine monophosphate (cAMP). This adrenergic response was attenuated by epidural analgesia.

Adenosine Diphosphate↗
PubMed1993

[Prevention and treatment of osteoporosis. A review of different methods].

This article reviews a number of methods for the treatment and prevention of osteoporosis. A preventive treatment achieves the best effect if it is started as soon after menopause as possible. Hormone substitution treatment has in many trials been shown to be effective in stopping the post-menopausal demineralization of the skeleton. Calcitonin is suggested as an alternative to hormone substitution, however this substance is still not registered in Denmark for this purpose. There are today several possible treatments for symptomatic osteoporosis; however, the long-term effect on frequency of new fractures remains to be confirmed. The regulation of a number of "life-style factors" such as diet and exercise is part of both the prevention and treatment of osteoporosis.

Aged↗
PubMed1993

[Salmon calcitonin in osteoporosis. The effect of intranasal application on bone mineral content and fracture frequency in postmenopausal women with manifest osteoporotic changes].

The objective was to study the dose-related response of intranasal salmon calcitonin (Salcatonin) on bone mass and bone turnover and the effect of salcatonin on rates of fracture in elderly women with moderate osteoporosis. A total of 208 healthy women aged 68-72 years, who had a bone mineral content (BMC) of the distal forearm 30% below the mean value for healthy premenopausal women, were examined in a double-blind, placebo-controlled, randomized group comparison study. They were randomized to a two-year daily treatment of either 50 IU, 100 IU, 200 IU Salcatonin or placebo. All received 500 mg calcium daily. In the calcium-(placebo)-treated group the BMC of the spine increased 1%, whereas an increase of 3% was seen in the 200 IU Salcatonin treated group. There was a dose-related response to Salcatonin manifested by an increase in BMC of 1.0%/100 IU. The incidence of new fractures was significantly lower in the women treated with Salcatonin (about one third of that in the non-Salcatonin treated women). In conclusion the results suggest that, compared with calcium alone, Salcatonin given intranasally reduces the rate of fracture by two thirds in elderly women with moderate osteoporosis. Furthermore, it increases spinal bone mass in a dose dependent manner.

Administration, Intranasal↗
PubMed1993

[No increase in the prevalence of vertebral fractures among postmenopausal women over a 10-year period].

We examined whether the prevalence of vertebral fracture in otherwise healthy, 70-year-old Danish women had increased over a period of ten years. The population-based, epidemiological study included two age-matched, representative samples of postmenopausal women. Group 1 (1979) consisted of 173 healthy women without secondary causes of osteoporosis, Group 2 (1989) of 387 women. X-rays of the thoraco-lumbar spine were assessed for vertebral fracture by five radiological methods. There was no significant difference between the two groups in the prevalence of vertebral fracture and the 95% confidence intervals overlapped completely in all methods. The prevalence rates varied by method from 35% to 80% but the distribution of fracture types was similar in the two groups. We conclude that the prevalence of vertebral fractures due to postmenopausal osteoporosis has not increased since 1979 in suburban Copenhagen, and that comparison of prevalences requires the same method of radiological assessment.

Aged↗
PubMed1993

Skeletal osteoporosis.

Osteoporosis is characterized by decreased bone mass and increased susceptibility to fractures. The clinical consequences of osteoporosis are fracture, most commonly seen at the wrist, the spine, and the hip. The prevalence of osteoporotic fracture is extremely high with 30%-40% of 70-year-old women having had at least one osteoporotic fracture. The prevalence in men is lower but may constitute a larger problem than expected. Osteoporotic fracture is, therefore, a significant cause of morbidity and mortality and represents a major problem of health care. Bone is the site of substantial metabolic exchanges, with bone resorption and formation continuing throughout life. The turnover processes are carried out by osteoclasts and osteoblasts in specialized cellular units. After cessation of growth, the skeleton probably consolidates to reach the peak bone mass at the age of 35-40 years. The relatively slow subsequent age-related bone loss occurs in both men and women, but women are additionally exposed to accelerated bone losses after the menopause. Estrogen deficiency is the dominating pathogenetic factor for osteoporosis in women. The role of disturbances in the calcium-regulating hormones and vitamin D deficiency is less sure. The pathophysiologic mechanisms of osteoporosis in men are not well investigated. Those who are endowed with a low peak bone mass and/or are exposed to a large bone loss are at particular risk of developing symptomatic osteoporosis. Several risk factors have been recognized but are insufficiently sensitive and specific to predict an individual's overall risk of developing osteoporosis.

Bone and Bones↗
PubMed1993

Effect of transdermal 17 beta-estradiol and oral conjugated equine estrogens on biochemical parameters of bone resorption in natural menopause.

OBJECTIVE: To evaluate and compare the effects or oral and transdermal estrogen replacement therapy on biochemical markers of bone resorption in early postmenopausal women. DESIGN: Controlled, randomized group comparison. SETTING: Outpatient clinic for menopausal women and research into osteoporosis. SUBJECTS: Sixty healthy women menopausal for less than 5 years and who had never received any medications interfering with bone metabolism. INTERVENTIONS: The 60 women were randomly allocated to 3 months therapy with either oral conjugated estrogens (0.625 mg/day) (n = 28) or transdermal estradiol (50 micrograms/day) (n = 32) in cyclical combination with medroxyprogesterone acetate (5 mg/day). MAIN OUTCOME MEASURES: Traditional (urinary calcium/creatinine and hydroxyproline/creatinine) and the new specific (urinary pyridinoline/creatinine and deoxypyridinoline/creatinine) markers of bone resorption were determined before and after 3 months of treatment. RESULTS: In both groups, circulating levels of estrone and estradiol were significantly (P < 0.001) increased during treatment. In women treated with oral conjugated equine estrogens, urinary calcium/creatinine and hydroxyproline/creatinine ratios were significantly (P < 0.05) reduced. Pyridinoline/creatinine ratio fell from 69.1 (4) [mean (SEM)] to 50 (4) mumol/mumol (P < 0.01) and deoxypyridinoline/creatinine ratio fell from 10.8 (1) [mean (SEM)] to 8.3 (0.8) mumol/mumol (P < 0.01). In the group treated with transdermal estradiol, urinary hydroxyproline/creatinine ratio was significantly (P < 0.05) reduced. Pyridinoline/creatinine ratio fell from 66.3 (4) [mean (SEM)] to 46.2 (3) mumol/mumol (P < 0.01) and deoxypyridinoline/creatinine ratio fell from 11.5 (1.5) [mean (SEM)] to 7.7 (0.6) mumol/mumol (P < 0.01). There were no differences between the evolution of the biochemical variables in the two groups. CONCLUSION: These results suggest that oral conjugated equine estrogens and transdermal estradiol, in the given doses, are equally effective in reducing postmenopausal bone resorption.

Administration, Cutaneous↗
PubMed1993

The effect of the menopause and hormone replacement therapy on serum carboxyterminal propeptide of type I collagen.

We investigated the effect of the menopause and postmenopausal hormone replacement therapy on the serum concentration of carboxyterminal propeptide of type I procollagen (PICP), which is a biochemical marker of type I collagen synthesis. A group of 124 healthy postmenopausal women, aged 45-53 years, had about 20% higher serum PICP than did a group of 40 healthy premenopausal women aged 35-52 years (114 +/- 35 micrograms/l vs. 95 +/- 26 micrograms/l (mean +/- SD); p = 0.002). The 124 postmenopausal women were also participating in a double-masked longitudinal study with two placebo groups and four different hormone replacement therapy groups. The four hormone regimens resulted in similar responses in serum PICP. Compared with placebo, 1 year of treatment with any of the four hormone replacement therapies significantly decreased serum PICP to premenopausal levels. We conclude that the formation of type I collagen is increased shortly after the menopause and that hormone replacement therapy reverses this increase.

Adult↗
PubMed1993

Human growth hormone and growth hormone releasing hormone: a double-masked, placebo-controlled study of their effects on bone metabolism in elderly women.

We treated 42 postmenopausal women with decreased bone mass for 12 weeks with human growth hormone, growth hormone releasing hormone, or placebo. Bone density and biochemical markers were determined before and during treatment, and 4 weeks after withdrawal. Biochemical markers of bone formation and resorption increased significantly in the group treated with growth hormone, whereas no changes were seen in the other groups. After withdrawal of therapy the bone markers declined without reaching baseline values. Bone density in the forearm, spine and proximal femur was unchanged in all groups. We conclude that treatment with growth hormone stimulates bone metabolism in elderly postmenopausal women with decreased bone mass.

Absorptiometry, Photon↗
PubMed1993

Running induces menstrual disturbances but bone mass is unaffected, except in amenorrheic women.

PURPOSE: To investigate the prevalence of exercise-related menstrual and sex hormonal disturbances and the effect of exercise on bone mass and metabolism in female runners at various training levels. SUBJECTS AND METHODS: Two hundred five premenopausal women (running 0 to 140 km a week) were recruited from a large population of female runners who had responded to a questionnaire regarding exercise habits. Maximum oxygen uptake was determined by treadmill testing. Gynecologic status was assessed on entries in a menstrual calendar and by transvaginal ultrasonography; sex hormonal status was measured three times with 10-day intervals. Bone mass was measured in the lumbar spine, proximal femurs, and total body by dual-energy x-ray absorptiometry, and in the forearm by single-photon absorptiometry. Bone turnover was assessed by measurement of plasma osteocalcin, serum alkaline phosphatase, and urinary calcium and hydroxyproline. RESULTS: Sex hormonal disturbances were significantly related to training intensity. Compared with the normally active women, the baseline levels and fluctuations of estradiol and progesterone in the elite runners were reduced by up to 25% to 44% (0.01 < p < 0.05). The prevalence of amenorrhea increased from 1% in the normally active subjects to 11% in the elite runners. No statistically significant relation was found between running activity and bone mineral measurements or bone turnover. However, the group of amenorrheic runners had a 10% reduction in lumbar bone density as compared with the normally menstruating runners (p < 0.05), but the bone turnover was similar. CONCLUSION: In the large majority of the female runners, no skeletal affection was found despite significant sex hormonal and menstrual disturbances. Only the runners with amenorrhea might be at increased risk of osteoporosis.

Adult↗
PubMed1993

Effect of an energy-restrictive diet, with or without exercise, on lean tissue mass, resting metabolic rate, cardiovascular risk factors, and bone in overweight postmenopausal women.

PURPOSE: To study the effect of exercise added to an energy-restrictive diet in overweight postmenopausal women. SUBJECTS AND METHODS: In a longitudinal clinical study, 121 healthy, overweight postmenopausal women (age 53.8 +/- 2.5 years, body mass index: 29.7 +/- 3.1 kg/m2) were randomly assigned to 3 groups: controls, a 4,200 kJ/d diet, or a 4,200 kJ/d diet with combined aerobic and anaerobic exercise. Body composition (measured by dual-energy x-ray absorptiometry), fat distribution, resting metabolic rate, blood pressure, serum lipids and lipoproteins, bone mineral densities, and markers of collagen and bone turnover were measured before and after 12 weeks of intervention. RESULTS: One hundred eighteen women completed the study. The mean loss of body weight (9.5 kg versus 10.3 kg, NS) was similar in the intervention groups, but compared with the diet-only group, the diet-plus-exercise group lost more fat (7.8 kg versus 9.6 kg, p < 0.001) and no lean tissue mass (1.2 kg versus -0.0 kg, p < 0.001). The resting metabolic rate (per kg wt) was increased in the diet-plus-exercise group compared with the control group (11% versus 4%, p < 0.009). The levels of serum triglycerides, total cholesterol, low-density lipoprotein, and very-low-density lipoprotein decreased, and the ratio of high-density lipoprotein to low-density lipoprotein increased by 20% to 30% in both intervention groups compared with the control group (p < 0.001). The systolic blood pressure dropped, and the waist-to-hip circumference ratio and abdominal-to-total body fat decreased in both intervention groups compared with the control group (10%, p < 0.003, and 3.5%, p < 0.0001). There were no consistent, major differences between the groups in terms of changes in total body, spinal, or forearm bone mineral densities, or in markers of collagen and bone turnover. CONCLUSION: Overweight postmenopausal women benefit from addition of combined aerobic and anaerobic exercise to an energy-restrictive diet. The diet itself has a positive effect on cardiovascular risk factors.

Blood Pressure↗
PubMed1993

Impact of regional and total body composition and hormones on resting energy expenditure in overweight postmenopausal women.

The independent impact of regional and total body composition and sex and thyroid hormone levels on resting energy expenditure (REE) was assessed in 121 healthy, overweight (body mass index [BMI], 25 to 42 kg/m2), postmenopausal women (aged 49 to 58 years). REE was measured by indirect calorimetry with a ventilated hood, and the total, trunk, and peripheral body composition by dual-energy x-ray absorptiometry (DXA). Sex and thyroid hormone levels were also measured. REE correlated significantly (P < .05) better with trunk lean tissue mass ([LTM] r = .61) than with total-body (r = .53) or peripheral LTM (r = .30). Trunk LTM (R2 = .37), total-body fat tissue mass ([FTM] R2 = .04), androstenedione (R2 = .03), and total triiodothyronine ([T3] R2 = .02) were all significantly independently associated with REE. Together they explained 46% (model R2) of the interindividual variation in REE, with a standard error of estimate (SEE) of 549 kJ/d. We conclude that the interindividual variation in REE is explained mainly by differences in the visceral component of LTM, with additional minor information from the total-body FTM, androstenedione, and T3.

Absorptiometry, Photon↗
PubMed1993

Accuracy of measurements of body composition by dual-energy x-ray absorptiometry in vivo.

The accuracy of body-composition measurements in vivo by dual-energy x-ray absorptiometry (DEXA) was assessed in seven pigs (weight: 35-95 kg) by measurement by DEXA in vivo and chemical analysis after postmortem homogenization. The regression lines between these measurements were not significantly different from the line of identity (P > 0.05), the r values were > 0.97, and the corresponding SEEs were 2.9%, 1.9 kg, and 2.7 kg for percent fat, fat tissue mass, and lean body mass, respectively. Changes in fat and lean tissue mass (simulated by placing 8.8 kg porcine lard on the trunk of six women) were accurately measured by DEXA. The measured total-body bone mineral (TBBM) was significantly affected by the lard (P < 0.05). In conclusion, DEXA is an accurate method for measurement of soft-tissue body composition. TBBM measurements in longitudinal studies may, however, be difficult to interpret if considerable change in soft-tissue composition has occurred.

Absorptiometry, Photon↗
PubMed1993

Wine for type 2 diabetic patients?

To ensure an acceptable quality of life for Type 2 diabetic patients, the food recommendations have to be as liberal and individualized as possible. Unfortunately, disagreements exists about the consumption of different types of wine. Diabetic patients are advised by some to restrain their wine intake and to use dry wine containing little carbohydrate, while others are more liberal. The purpose of this study was to evaluate the effects of dry and sweet wine on the glycaemic control in Type 2 diabetes. Twelve diabetic patients consumed a light meal with either 300 ml tap water 300 ml dry white wine, 300 ml sweet white wine with ethanol added or 300 ml dry white wine with glucose added. Similar glucose, insulin, and triglyceride responses were obtained in all four situations. There was a greater suppression of the free fatty acid levels in the three situations with wine as compared with water (p < 0.001). This effect may be caused by an attenuation of the free fatty acid mobilization and esterification of free fatty acids to triglycerides induced by alcohol. Our results indicate that patients with well-controlled Type 2 diabetes can drink moderate amounts of wine with meals without risking acute deterioration of glycaemic control. Whether the wine is dry or sweet has no impact on the glycaemic control.

Adult↗
PubMed1993

Low bone mass and high bone turnover in male long distance runners.

Running is a popular sport, but in some studies long distance running in women has been related to reduced bone mass and a potential risk of osteoporosis. To investigate the impact of running on bone mass in men, 120 healthy, physically active men (19-56 yr old; running 0-160 km/week) were studied. Bone mineral content was measured in the lumbar spine, total body, and proximal femurs by dual energy x-ray absorptiometry and in the forearm by single photon absorptiometry. Bone turnover was assessed by urinary pyridinium cross-links, plasma osteocalcin, and serum alkaline phosphatase. Lumbar bone mineral content was negatively correlated to the weekly distance run (r = -0.37; P < 0.0001), with a difference of 19 +/- 5% (mean +/- SEM) between controls and elite runners. A similar relation was found for all measurement sites. After adjustment for possible confounders, the correlations remained statistically significant in areas with a high proportion of trabecular bone. Bone turnover parameters were 20-30% higher in the elite runners, whereas sex hormone status was unrelated to running activity. We conclude that male long distance runners had reduced bone mass and increased bone turnover compared to controls, which suggests accelerated bone loss. The pathophysiological explanation was not clear, but sex hormones did not seem to play a key role.

Adult↗