Acute posterior myocardial infarction in a 16-year-old heart transplant recipient.
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Adolescent↗
Biomedical subjects
A Zittermann
Publications and source records attributed to A Zittermann.
Organs from donors with primary brain malignancy: the fate of cardiac allograft recipients.
BACKGROUND: The phenomenon of malignancy transmission from donors with primary brain malignancy (PBM) which is relatively well documented in renal or liver transplant recipients, has not been analyzed in cardiac allograft recipients. METHODS: We reviewed the medical records of 32 cardiac allograft recipients who were transplanted with organs from donors suffering from primary brain malignancies from 1989 to 2003. RESULTS: No case of donor-transmitted malignancy has been reported with a mean follow-up of 80.6 months. CONCLUSIONS: In our experience as well as according to a review of the literature, the risk of tumor transmission from donors with primary brain malignancy to cardiac allograft recipients seems to be extremely low. In the context of the increased donor shortage, we recommend to accept all suitable cardiac allografts harvested from donors with primary brain malignancy provided there are no detectable remote metastases.
Autopsy↗
Carbamazepine does not alter biochemical parameters of bone turnover in healthy male adults.
It is still not completely clear whether or not carbamazepine (CBZ) causes alterations in vitamin D status and in bone metabolism. The objective of this study was therefore to investigate prospectively in healthy adults the effects of CBZ on serum levels of 25-hydroxyvitamin D (25OHD) and on biomarkers of bone formation and resorption. Twenty-one free-living male adults were taking 800 mg/day CBZ for 10 weeks. The study was performed from December 1997 until September 1998 at a geographic latitude of 51 degrees N. Blood samples were collected before treatment (t1), 33 days (SE 2.5) after starting treatment (t2), and 70 days (SE 3.6) after starting treatment (t3). In 13 out of the 21 subjects blood samples were also drawn 64 days (SE 9.0) after treatment had been terminated (t4). Serum 25OHD levels remained constant during study periods t1-t3. 25OHD levels were, however, significantly higher at t4 compared to t1-t3. Serum concentrations of intact osteocalcin, a bone formation marker, and C-telopeptide, a bone resorption marker, were similar during all examinations. Moreover, serum levels of parathyroid hormone, calcium, and inorganic phosphate did not change. Data indicate that CBZ per se does not alter bone metabolism and does not lead to decreased circulating 25OHD levels in young males without epilepsy. Variations in 25OHD levels are in line with the seasonal fluctuations in vitamin D status.
Administration, Oral↗
[German physicians discover a possible correlation. Heart failure caused by vitamin D deficiency? (interview by Dr. Kirsten Westphal)].
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Heart Failure↗
Body mass index and disease duration are predictors of disturbed bone turnover in anorexia nervosa. A case-control study.
OBJECTIVE: To characterize the influence of body mass index (BMI), body composition, hormonal factors and disease duration on bone metabolism markers in anorexia nervosa (AN) patients. DESIGN: Case-control study with 51 AN patients and 51 controls matched for age, sex and body height. Assessment of anthropometric and bioimpedance data, and of biochemical serum parameters and of oral contraceptives use. RESULTS: Patients had a lower BMI, lower fat mass, lower fat-free mass and lower muscle mass (MM) compared to the controls (all P values <0.001). Moreover, serum levels of osteocalcin (bone formation marker) were lower while serum C-telopeptide concentrations (CTx; bone resorption marker) and the CTx/osteocalcin ratio (an index reflecting the balance of bone remodeling) were higher in the AN patients compared to the controls (P<0.01-0.001). In addition, patients had enhanced serum calcium and cortisol levels and reduced serum levels of thyroid hormones, insulin, and leptin (P values <0.05-0.001). Mean disease duration was 91+/-13 months. In a multiple regression analysis, BMI (P<0.0001), MM (P<0.005) and duration of the disease (P<0.005) were independent predictors of the CTx/osteocalcin ratio in the AN patients. There was a nonlinear association between BMI and the CTx/osteocalcin ratio of r=-0.72 (P<0.001) in the AN patients, but only a weak relation of r=-0.27 (P<0.05) between these parameters in the control subjects. Use of oral contraceptives had no effect on the CTx/osteocalcin ratio, neither in AN patients nor in controls. CONCLUSIONS: Data indicate an uncoupling of bone formation and bone resorption in AN, which is primarily the result of a low BMI and influenced by the duration of the disease.
Adolescent↗
[Phytoestrogens].
The soy-isoflavones genistein and daidzein and the flaxseed-lignans secoisolariciresinol and matairesinol belong to the group of phytoestrogens. Epidemiological data suggest that phytoestrogens have a preventive effect against various estrogen-related diseases/symptoms such as breast cancer, menopausal symptoms, cardiovascular diseases, and osteoporosis. To prove these assumptions, available controlled clinical trials have been critically reviewed. Especially soy-isoflavones have been extensively studied. There is no scientific evidence for an effect of phytoestrogens on menopausal symptoms and risk factors of breast cancer. However, isoflavones-containing soy protein can lower total cholesterol, LDL cholesterol, and triglyceride serum levels. The strongest evidence exists for a preventive effect of soy isoflavones on postmenopausal bone loss of the lumbar spine. Distinct effects on estrogen-related diseases can be explained at least in part by the different affinity of isoflavones to estrogen receptors alpha and beta and the distinct tissue distribution of these receptors.
Anticarcinogenic Agents↗
Evidence for an acute rise of intestinal calcium absorption in response to aerobic exercise.
BACKGROUND: The acute effects of physical activity on intestinal calcium (Ca) uptake and on bone metabolism are not known. AIM OF THE STUDY: To investigate the consequences of an acute aerobic exercise bout on fractional Ca absorption and on biomarkers of bone turnover. METHODS: With the use of a cross over design, eighteen male athletes, aged 25.2 (SE 0.6) years, either had to perform a 60 min run (70 % of maximal speed) or had to rest for 60 min. Intestinal Ca absorption (Fc(240)) was assessed by the use of a stable strontium test. Moreover, calciotropic hormones and serum C-Telopeptide (CTx), a biomarker of bone collagen degradation, and serum C-terminal propeptide of type I collagen (PICP), a marker of bone collagen formation, were measured prior (t(-60)) and 3 hours after (t(240)) exercise or rest. RESULTS: Fc(240) values were significantly enhanced in response to exercise compared to rest (16.2 +/- 0.7 % vs. 14.6 +/- 0.8 %; P < 0.05). PICP values were significantly lower in response to exercise compared to rest: -9.8 % (P < 0.05). Exercise did not influence serum levels of intact parathyroid hormone and calcitriol. Serum CTx levels decreased markedly between t(-60) and t(240) during both intervention periods (both P values < 0.001), the results being in line with the circadian rhythm of serum CTx. CONCLUSIONS: A moderate exercise bout can induce an acute rise in fractional Ca absorption. Moreover, even in endurance-trained young men a moderate exercise bout acutely decreases bone collagen formation, while the physiologic fluctuations of the bone resorption marker CTx remain unaffected.
Adult↗
Oral contraceptives moderately effect bone resorption markers and serum-soluble interleukin-6 receptor concentrations.
This study investigated the effect of ethinylestradiol(EE2)-containing oral contraceptives on mineral and bone metabolism and on serum soluble-interleukin-6-receptor (sIL-6R) during the menstrual cycle. Twelve women, aged 24.3 +/- 2.9 years, were examined. Blood and 24-hour and fasting urine samples were obtained during one menstrual cycle between cycle day 3-5 (t(1)), cycle day 10-12 (t(2)), cycle day 24-26 (t(3)), and again on day 3-5 of the next cycle (t(4)). EE2 intake was 0 mg at t(1), 30 mg at t(2), 30 mg at t(3) and 0 mg at t(4). Fasting renal phosphorus and calcium excretions were slightly reduced at t(2) and t(3) compared with t(1) and t(4) (P < 0.05-0.001). Moreover, renal excretion of the bone resorption marker C-Teleopeptide was at t(3) reduced by 26% compared with t(1)(P < 0.01) and by 13% compared with t(4)(P > 0.05). Fasting sIL-6R levels were 16.5% lower at t(2) and 12% lower at t(3) than at t(4) (P < 0.01 and P < 0.05). sIL-6R was correlated with total deoxypyridinoline excretion (r = +0.35; P < 0.05) and with fasting renal excretions of calcium (r = +0.36; P < 0.05) and phosphorus (r = +0.29; P < 0.05). In summary, our data suggest that in young women, cyclic monthly oral contraceptive intake is associated with small, but significant variations in bone resorption processes and in serum sIL-6R levels. Results are a further indication that monthly fluctuations of bone resorption in young women are mediated by sex hormones and that osteoclastic activity is stimulated by cytokines in vivo.
Adult↗
Effects of vitamin K on calcium and bone metabolism.
The K vitamins, a group of napthoquinones, are required for the carboxylation of a limited number of proteins including the bone matrix protein osteocalcin. Vitamin K1 (phylloquinone) and vitamin K2 (menaquinones), differ regarding food source (green vegetables and fermented products, respectively), bioavailability and intermediate metabolism. Epidemiological studies provide evidence for an association between a low vitamin K intake and an enhanced osteoporotic fracture risk. Doses of vitamin K1 up to 15 times the current recommended dietary allowance have successfully been used to reduce the percentage of undercarboxylated osteocalcin in the circulation. Studies demonstrating clear beneficial effects on bone health, however, are still lacking. In contrast, therapy with very high pharmacological doses of the vitamin K2 menatetrenone has impressively been used to prevent further bone mineral loss and fracture risk in osteoporotic patients.
Biological Availability↗
Seasonal variation in bone turnover: dependence on calcium nutrition.
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Amino Acids↗
Nitrogen metabolism and bone metabolism markers in healthy adults during 16 weeks of bed rest.
BACKGROUND: The associations between nitrogen metabolism and bone turnover during bed rest are still not completely understood. METHODS: We measured nitrogen balance (nitrogen intake minus urinary nitrogen excretion) and biochemical metabolic markers of calcium and bone turnover in six males before head-down tilt bed rest (baseline), during 2, 10, and 14 weeks of immobilization, and after reambulation. RESULTS: The changes in nitrogen balance were highest between baseline and week 2 (net change, -5.05 +/- 1.30 g/day; 3.6 +/- 0.6 g/day at baseline vs -1.45 +/- 1.3 g/day at week 2; P<0.05). In parallel, serum intact osteocalcin (a marker of bone formation) was already reduced and renal calcium and phosphorus excretions were increased at week 2 (P <0.05). Fasting serum calcium and phosphorus values and renal excretion of N-telopeptide (a bone resorption marker) were enhanced at weeks 10 and 14 (P <0.05-0.001), whereas serum concentrations of parathyroid hormone, calcitriol, and type I collagen propeptide (a marker of bone collagen formation) were decreased at week 14 (P <0.05-0.01). Significant associations were present between changes of serum intact osteocalcin and 24-h calcium excretion (P <0.001), nitrogen balance and 24-h phosphorus excretion (P <0.001), nitrogen balance and renal N-telopeptide excretion (P <0.05), and between serum osteocalcin and nitrogen balance (P <0.025). CONCLUSIONS: Bone formation decreases rapidly during immobilization in parallel with a higher renal excretion of intestinally absorbed calcium. These changes appear in association with the onset of a negative nitrogen balance, but decreased bone collagen synthesis and enhanced collagen breakdown occur after a time lag of several weeks.
Adult↗
Exercise-trained young men have higher calcium absorption rates and plasma calcitriol levels compared with age-matched sedentary controls.
The effect of physical activity on human calcium (Ca) metabolism is still not completely understood. Thus, we investigated fractional Ca absorption using a stable strontium test (Fc(240)), calciotropic hormones, and renal Ca excretion in 31 young men with a high activity level (GH) and in 26 age-matched sedentary control subjects (GL). Weekly hours spent on physical activity, obtained with a questionnaire were 15.0 +/- 6.6 (GH) and 1.0 +/- 1.4 (GL), respectively. Serum testosterone levels were significantly lower in GH compared with GL (P < 0.005). Dietary Ca intake (4-day food record) was twice as high in GH compared with GL men (P < 0.001). GH had significantly higher serum calcitriol levels and Fc(240) values than GL (P < 0.001 and P < 0.01, respectively). In a stepwise multiple regression analysis including serum levels of 25-hydroxyvitamin D, calcitriol, testosterone, and dietary Ca intake, only calcitriol was significantly correlated with Fc(240) (P = 0. 017). Twenty-four hour renal Ca excretion was only slightly higher in GH compared with GL (P < 0.05). However, additional Ca losses might have occurred through the extensive sweating of GH, as indicated by a difference of 1.7 liter between fluid intake and renal fluid excretion (P < 0.001). In summary, we observed a higher fractional Ca absorption rate in physically active young men compared with sedentary controls which is probably mediated by calcitriol. The low testosterone serum levels of the athletes were obviously not a limiting factor in Ca absorption efficiency. An additional Ca retention might, however, only be obtained if absorbed Ca exceeded total obligatory Ca losses.
Adult↗
Microgravity inhibits intestinal calcium absorption as shown by a stable strontium test.
BACKGROUND: Little is known about the onset and degree of biochemical and functional alterations in calcium metabolism during microgravity. OBJECTIVE: To evaluate the effect of microgravity on intestinal calcium absorption and calcium-regulating hormones under metabolic ward conditions. MATERIALS AND METHODS: Fractional calcium absorption (Fc240 in percentage of dose administered) was determined pre-flight, in-flight and post-flight, by use of a stable strontium test in one cosmonaut who spent 20 days in space. Moreover, a sequence of blood samples was collected for the determination of serum parathyroid hormone (PTH), 25-hydroxyvitamin D, calcitriol and serum C-telopeptide (CTx, biomarker of bone resorption) levels. During all periods of data collection, calcium intake was held constant at a minimum level of 1.000 mg day(-1) and a daily supplement of 16.6 microg vitamin D2 was given. Personal ultraviolet (UV) light exposure was measured during the whole mission using a biologically weighting UV dosimeter. RESULTS: Fc240 was markedly reduced on flight day 19 (4.4%) as compared to pre-flight and post-flight data (13.4% and 17.2%, respectively). Serum calcitriol levels fell from 40.6 pg mL(-1) (mean pre-flight level) to 1.3 pg mL(-1) on flight day 18 and returned into the normal range after recovery. Serum CTx increased during the flight, while serum PTH and 25-hydroxyvitamin D levels did not change significantly. CONCLUSIONS: Intestinal calcium absorption can be diminished after only three weeks of microgravity. Changes are associated with a severe suppression of circulating calcitriol levels, but are independent of exogenous vitamin D supply and serum PTH levels.
Adult↗
Decreased urinary calcium loss and lower bone turnover in young oral contraceptive users.
The effect of ethinyl estradiol-containing oral contraceptives (OCs) on bone health is still not completely understood. This study was therefore performed to investigate the effect of OC use on biochemical parameters of calcium (Ca) and bone metabolism in young women. Twelve OC users ([OC+ group] age, 24.8 +/- 0.6 years) and 19 eumenorrheic nonusers ([OC-group] age, 25.5 +/- 0.8 years) were studied. Three individual urine samples (fasting 2-hour and 24-hour specimen) and 3 blood samples collected at intervals of 28 days were pooled for data evaluation. Energy, nutrient intake (7-day food record), the body mass index, and serum 25-hydroxyvitamin D levels of the 2 groups were comparable. Serum levels of estradiol (E2) and sex hormone-binding globulin (SHBG) in the 2 groups mirrored the use and nonuse of OCs. Fasting 2-hour renal Ca excretion was markedly lower in the OC+ group compared with the OC- group (80.2 +/- 14.7 v 185.1 +/- 18.8 micromol/mmol creatinine [Cr], P < .001), indicating a decrease in the urinary loss of endogenous, bone-derived Ca. Moreover, 24-hour renal Ca excretion was reduced in the OC+ group (3.65 +/- 1.46 v5.03 +/- 1.90 mmol/d, respectively, P < .01). In addition, serum Ca levels were lower in the OC+ group versus the OC- group (2.19 +/- 0.07 v 2.29 +/- 0.02 mmol/L; P < .05). The OC+ group had lower serum levels of carboxy-terminal propeptide of type I procollagen ([PICP] a biomarker of bone formation) compared with the OC- group (78.3 +/- 3.6 ng/mL in the OC+ group v 96.9 +/- 5.5 ng/mL in the OC- group, P < .001) and lower renal hydroxyproline (OHPr) excretion (a biomarker of bone resorption, 8.3 +/- 1.0 v 11.3 +/- 1.0 micromol/mmol, Cr, P < .001). In summary, OCs reduce urinary Ca loss and slow bone turnover in young women. The results may help to explain the OC effect on bone mass in young women.
Adult↗
Lactose does not enhance calcium bioavailability in lactose-tolerant, healthy adults.
BACKGROUND: There is evidence from animal studies that lactose has a beneficial effect on intestinal calcium absorption. However, data concerning the effect of lactose on calcium absorption in lactose-tolerant adults are inconclusive. OBJECTIVE: Our objective was to investigate the effect of lactose on calcium bioavailability in humans by the use of a stable-strontium test under controlled metabolic conditions. DESIGN: Eleven healthy, lactose-tolerant subjects (8 women, 3 men) randomly received a bolus of 2.27 mmol strontium alone (load A), the bolus with 35 g lactose (load B), or the bolus with 17.5 g glucose and 17.5 g galactose (load C). Blood samples were drawn at 0, 15, 30, 60, 90, 180, 240, and 300 min. Urine specimens were collected during the time intervals -2 to 0, 0-2, 2-4, 4-6, and 6-24 h. RESULTS: Pharmacokinetic parameters of strontium bioavailability were comparable for all 3 loads. In detail, fractional absorption at 240 min for loads A, B, and C was 12.1 +/- 0.7%, 13.0 +/- 1.1%, and 12.2 +/- 0.7%, respectively. Areas under the curve for 0-240 min were 70.8 +/- 6.3, 69.6 +/- 3.5, and 65.8 +/- 5.1 micromol*h/L for loads A, B, and C, respectively (NS). Moreover, fractional strontium excretion values of 5.1 +/- 0.8% (load A), 5.8 +/- 0.4% (load B), and 5.2 +/- 0.8% (load C) were not significantly different. CONCLUSIONS: Lactose does not have a beneficial effect on calcium bioavailability in lactose-tolerant adults.
Adult↗
Physiologic fluctuations of serum estradiol levels influence biochemical markers of bone resorption in young women.
We investigated the effect of physiologic variations in sex hormone levels during the menstrual cycle on biomarkers of bone turnover. Blood and 24-h and fasting urine samples were obtained in nine women (age, 25.1+/-3.0 yr) with regular menstrual cycles during the early follicular period (t1), 3 days before ovulation (t2), 3 days after ovulation (t3), at the midluteal period (t4) and again during the early follicular period of the next cycle (t5). All subjects had a calcium intake covering current dietary recommendations (above 1,000 mg/day, standardized food record). Serum calcium, phosphorus, calcitriol, 24-h and 2-h fasting urinary calcium, and phosphorus excretion remained constant during the menstrual cycle. Serum 25-hydroxyvitamin D3 levels decreased slightly from the beginning until the end of the study (P<0.05), indicating low cutaneous vitamin D synthesis during wintertime. The serum levels of sex hormones showed typical monthly variations, with the lowest estradiol (E2) levels at t1 and t5. Fasting 2-h pyridinoline (Pyd) concentrations (a marker of bone resorption) fell from t1 to t3 and rose again at t5 (P<0.01). Similar variations were observed for the resorption marker deoxypyridinoline (Dpd; P<0.05). The amplitude of the two biomarkers was 32% and 33%, respectively. The serum levels of the carboxyterminal propeptide of type I collagen (a marker of bone formation) showed an inverse cyclic pattern, as compared with the pyridinium cross-links. Low concentrations were observed at t1; a rise occurred until t3 and was followed by a decrease until t5 (P<0.05). A similar cyclic pattern was observed for serum PTH levels, with the highest concentrations at t3 (P<0.05). Dpd and Pyd values were significantly correlated with serum E2 levels (r = 0.52; P<0.0001 and r = 0.50; P<0.001, respectively). Neither progesterone nor LH nor FSH was correlated with Pyd or Dpd levels. The data suggest that normal menstrual cycling in young women is associated with monthly fluctuations in bone turnover. This physiological effect of the menstrual cycle is most probably related to variations in serum E2 concentrations.
Adult↗
Calcium metabolism in microgravity.
Unloading of weight bearing bones as induced by microgravity or immobilization has significant impacts on the calcium and bone metabolism and is the most likely cause for space osteoporosis. During a 4.5 to 6 month stay in space most of the astronauts develop a reduction in bone mineral density in spine, femoral neck, trochanter, and pelvis of 1%-1.6% measured by Dual Energy X-ray Absorption (DEXA). Dependent on the mission length and the individual turnover rates of the astronauts it can even reach individual losses of up to 14% in the femoral neck. Osteoporosis itself is defined as the deterioration of bone tissue leading to enhanced bone fragility and to a consequent increase in fracture risk. Thinking of long-term missions to Mars or interplanetary missions for years, space osteoporosis is one of the major concerns for manned spaceflight. However, decrease in bone density can be initiated differently. It either can be caused by increases in bone formation and bone resorption resulting in a net bone loss, as obtained in fast looser postmenopausal osteoporosis. On the other hand decrease in bone formation and increase in bone resorption also leads to bone losses as obtained in slow looser postmenopausal osteoporosis or in Anorexia Nervosa patients. Biomarkers of bone turnover measured during several missions indicated that the pattern of space osteoporosis is very similar to the pattern of Anorexia Nervosa patients or slow looser postmenopausal osteoporosis. However, beside unloading, other risk factors for space osteoporosis exist such as stress, nutrition, fluid shifts, dehydration and bone perfusion. Especially nutritional factors may contribute considerably to the development of osteoporosis. From earthbound studies it is known that calcium supplementation in women and men can prevent bone loss of 1% bone per year. Based on these results we studied the calcium intake during several European missions and performed an experiment during the German MIR 97 mission where we investigated the effects of high calcium intake (>1000 mg/d) and vitamin D supplementation (650 IU/d) on the calcium and bone metabolism during 21 days in microgravity. In the MIR 97 mission high calcium intake and vitamin D supplementation led to high ionized calcium levels and a marked decrease in calcitriol levels together with decreased bone formation and increased bone resorption markers. Our conclusion from the MIR 97 mission is that an adequate calcium intake and vitamin D supplementation during space missions is mandatory but, in contrast to terrestrial conditions, does not efficiently counteract the development of space osteoporosis.
Bone and Bones↗
Wheat bran supplementation does not affect biochemical markers of bone turnover in young adult women with recommended calcium intake.
We investigated the effect of wheat bran on biochemical indicators of Ca and bone metabolism in nineteen healthy women, aged 25.5 (SE 0.9) years. Subjects received six wheat bran biscuits or six white flour biscuits per day for a period of 4 weeks (crossover). Wheat bran consumption increased fibre intake from 17.7 (SE 1.3) to 29.6 (SE 1.3) g/d (7 d food record) and enhanced P intake from 1225 (SE 59) mg/d to 1663 (SE 65) mg/d; P < 0.001. Mean daily Ca intake during wheat bran consumption (1110 (SE 82) mg/d) significantly (P = 0.008) exceeded Ca ingestion during the white flour period (955 (SE 67) mg/d). Wheat bran increased the number of defecations per week from 7.9 (SE 0.8) to 12.2 (SE 1.4) (P = 0.0018). Urinary Ca excretion over 24 h significantly (P = 0.021) decreased from 473 (SE 53) mumol/mmol creatinine (control period) to 339 (SE 37) mumol/mmol creatinine (wheat bran period). Serum 25-hydroxyvitamin D, 2 h fasting urinary Ca/creatinine excretions and 24 h urinary P excretion remained constant. No differences in serum levels of carboxy-terminal propeptide of type I procollagen (biomarker of bone formation) or in 2 h fasting urinary hydroxyproline/creatinine excretions (biomarker of bone resorption) were observed at the end of the two cycles of dietary supplementation. We conclude that a high fibre intake of approximately 30 g/d has no significant adverse effects on bone turnover in subjects with Ca intakes above 1000 mg/d and that the reduction in 24 h urinary Ca excretion is most probably the result of an adaptation process, induced by a decrease in net absorbed Ca.
Adult↗