Biomedical subjects

W Ambrosius

Publications and source records attributed to W Ambrosius.

8 recordsLinked to original sources

PubMed2001

[Leukocytosis in the first day of acute ischemic stroke as a prognostic factor of disease progression].

It has been reported that white blood cells (WBC) may contribute to the initiation and further development of stroke. WBC count could have influence on hemorheology, thrombosis and induction of vasoconstriction in cerebral arteries. The aim of this work was to determine whether WBC count assessed in patients with acute stroke in the first day of the disease have a predictive value for the late clinical outcomes. Peripheral WBC count was measured at the admission to the hospital in 100 consecutive patients with acute stroke. Ischemic stroke was confirmed in all patients by head CT. Neurological status was evaluated with the use of modified Rankin's Scale. We assessed the following clinical outcomes: in-hospital mortality, the lack of neurological improvement on the 21st day of disease, and the need for hospital stay longer than 21 days. Odds ratio (OR) with 95% confidence interval (95% CI) adjusted for patient's age, gender, cardiovascular diseases, diabetes mellitus and previous stroke was calculated with the use of logistic regression. OR was evaluated both for the presence of WBC count > 10.000 cells/microliter and for each 1000 leukocytes/microliter increase. WBC count greater than 10.000 cells/microliter was associated with a more than seventy-fold greater risk for death (OR--75.18; 95% CI: 8.89-635.84; p = 0.0001), nearly eight times increased risk for the no-improvement status (OR--7.78; 95% CI: 2.51-24.17; p = 0.0004) and approximately four times increased risk for the prolonged hospital stay (OR--4.20; 95% CI: 1.50-11.72; p = 0.0062). Each 1000 cell/microliter increase in WBC count at the admission was associated with increased risk for in-hospital mortality (OR--2.24; 95% CI: 1.39-3.57; p = 0.0008), no neurological improvement (OR--1.43; 95% CI: 1.15-1.76; p = 0.0009) and the need for prolonged hospitalization (OR--1.26; 95% CI: 1.07-1.49; p = 0.0066). Increased WBC count within the first 12 hours of stroke is an independent and strong risk factor for mortality, no neurological improvement, and the need for prolonged hospitalization in the course of acute ischemic stroke.

Aged↗

PubMed2000

Patients' perception of stopping or continuing treatment of cervical dystonia with botulinum toxin type A.

Despite widespread commercial acceptance of botulinum toxin (BTX) for idiopathic cervical dystonia (ICD), no follow up has been performed to determine when and why some patients stop therapy. It has been suggested that some patients who stop BTX treatment may do so because of permanent improvement. We surveyed 155 patients with ICD who were treated over 6 years with BTX to determine when and why patients stopped treatment with BTX, and what adverse events and changes in dose and/or frequency of treatments occurred in those who continued treatment. Of the 133 (86.6%) individuals returning the surveys, 104 continued on BTX treatment and 29 had stopped therapy. Of the 29 subjects no longer receiving BTX, 11 individuals had only received one or two injections. Prior surgical treatment for ICD did not influence their decision to stop therapy. Of those 104 of 133 continuing on BTX treatments, two thirds of the subjects reported the injections always help, whereas one quarter estimated one set of injections did not help. One third of those continuing treatment reported the first injection was most helpful, whereas another one third felt all injections were similarly effective. After an initial adjustment, BTX dosages and frequency of treatment remained stable in this group.

Adult↗

PubMed2000

Forced expiratory flows and volumes in infants. Normative data and lung growth.

Forced expiratory flows (FEF) can be measured in infants from lung volumes initiated near total lung capacity. In order to establish reference values and to evaluate lung growth, we obtained measurements in 155 healthy subjects between 3 and 149 wk of age. Forced vital capacity (FVC) was highly correlated with body length; however, after accounting for length, age was also significant. When subjects were divided at the median age (40 wk) younger compared with older subjects had a significantly larger slope for length (3.7 versus 2.8; p = 0.002). The flow parameters (FEF(50), FEF(75), FEF(85), and FEF(25-75)) were highly correlated with length, and those infants whose mothers smoked had lower flows. For FEF(75), male subjects had lower flows than female subjects. The relationship between FEF and volume was assessed using FEV(0.5)/FVC, which decreased with increasing length. Smaller subjects emptied their lung volume proportionately faster. We conclude that our study provides reference values for this age group and demonstrates that smoke-exposed infants and male subjects have decreased FEF. In addition, our findings indicate that lung volume increases most rapidly during the first year of life and that airways are large relative to lung volume very early in life.

Anthropometry↗

PubMed2000

Effect of calcium or 25OH vitamin D3 dietary supplementation on bone loss at the hip in men and women over the age of 60.

Dietary supplements that prevent bone loss at the hip and that can be applied safely in the elderly are likely to reduce hip fractures. A daily dietary supplement of 750 mg calcium or 15 microg 25OH vitamin D3 on bone loss at the hip and other sites, bone turnover and calcium-regulating hormones were studied over 4 yr in elderly volunteers using a randomized, double-blind, placebo-controlled trial. Bone mineral density (BMD) was measured by dual x-ray absorptiometry and bone structure by radiographs. Calcium biochemistry and bone turnover markers were measured in blood and urine. The 316 women entering the trial had a mean age of 73.7 yr and the 122 men of 75.9 yr. Baseline median calcium intake was 546 mg/day, and median serum 25OH vitamin D3 was 59 nmol/L. On placebo, loss of BMD at total hip was 2% and femoral medulla expansion was 3% over 4 yr. Calcium reduced bone loss, secondary hyperparathyroidism, and bone turnover. 25OH vitamin D3 was intermediate between placebo and calcium. Fracture rates and drop-out rates were similar among groups, and there were no serious adverse events with either supplement. A calcium supplement of 750 mg/day prevents loss of BMD, reduces femoral medullary expansion, secondary hyperparathyroidism, and high bone turnover. A supplement of 15 microg/day 25OH vitamin D3 is less effective, and because its effects are seen only at low calcium intakes, suggests that its beneficial effect is to reverse calcium insufficiency.

Aged↗

PubMed1998

Bone mass and structure at the hip in men and women over the age of 60 years.

Bone mass and structure at the proximal femur are important predictors of hip fracture. The aims of this study were to compare in a large sample of elderly men and women the precision of measurements of bone mass and structure at multiple sites at the proximal femur, to examine their interrelationships, to establish their relationships with age and body size, and to examine criteria for defining geometric and architectural variables in bone structure. Women (n = 336) and men (n = 141) over the age of 60 years were studied cross-sectionally. Bone mineral density (BMD) and content (BMC) at the proximal femur were measured in duplicate by dual-energy X-ray absorptiometry (DXA). Shaft and total upper femur (hip) sites in addition to femoral neck, Ward's triangle and trochanter were measured. Structural variables, measured from radiographs and from DXA images, including cortical thickness at calcar femorale, lateral cotex and midfemur, width of the femur and medulla, Singh grade, hip and femoral axis length, femoral head and neck width and the center of mass of the femoral neck. BMD and BMC had high reproducibility and there were significant differences in reproducibility across sites. Among sites, total upper femur and shaft had the highest reproducibility. Duplicate measurements substantially improved reliability of the measurement and are recommended when the value is close to a diagnostic level or when it will be used to establish rates of change. Reproducibility of structural variables was also high except for the lateral cortex, center of mass and Singh grade. Variance due to measurement error did not change with either age or gender. Women were significantly different from men, after controlling for differences in body size, in all variables except Singh grade and medulla width. BMD and BMC were negatively related to age and positively to body size. Structural variables examined in relation to age and body size fell into two categories. The first comprised variables that were not age-related but were body-size-related suggesting that they could be classified as geometric variables. The second comprised variables that were both body-size-related and age-related, suggesting that they could be classified as architectural variables. Using these criteria, calcar and lateral cortex were architectural variables, whereas shaft width, hip and femoral axis length, femoral head and neck width, and center of mass were geometric in both men and women. In women, shaft cortex width and medulla width were age-related, whereas in men they were not. Singh grade showed no consistent pattern with age or body size in women and men.

Absorptiometry, Photon↗

PubMed1998

Does microdamage accumulation affect the mechanical properties of bone?

It has never been demonstrated that microcrack accumulation in bone leads to impaired mechanical properties. We hypothesized that microdamage accumulation is positively and linearly correlated with a reduction in bone's elastic modulus. We also tested the hypothesis that damage accumulates more rapidly in tensile cortices, but crack growth is greater in compressive cortices. Canine femurs (n = 26) were tested in four-point cyclic bending under load control until they had lost between 5 and 43% of their stiffness. Ten femurs were used as nonloaded controls. The loaded portion of the bone was stained en bloc with basic fuchsin to detect the presence of microdamage. The number of stained microcracks, their lengths and the area of damaged bone were measured under the microscope. Crack numerical density, surface density, mean crack length, and the percentage of damaged area were calculated. Significant microdamage accumulation was not detected until the bone had lost 15% of its elastic modulus. The relationship between crack density and stiffness loss was approximately quadratic, but the relationship between damaged area and stiffness loss was linear. There were significantly more microcracks in tensile cortices, but on average cracks were significantly longer in compressive cortices. We conclude that microcrack accumulation impairs the mechanical properties of bone by reducing its elastic modulus. We also conclude that damage accumulates more rapidly in tensile cortices, but crack growth is greater in compressive cortices.

Animals↗

PubMed1997

Lower respiratory illness in infants and young children with cystic fibrosis: evaluation of treatment with intravenous hydrocortisone.

The purpose of our study was to assess the effect on pulmonary function of adding intravenous hydrocortisone to the standard treatment of infants with cystic fibrosis (CF) hospitalized for lower respiratory illnesses (LRI). Twenty CF infants were randomized and received 10 days of hydrocortisone (10 mg/kg/day) or placebo in addition to standard treatment with intravenous antibiotics, chest physiotherapy, and an aerosolized beta-agonist with cromolyn. Functional residual capacity (FRC) and forced expiratory flows (V'mak,FRC) were measured on admission, on Day 10 of hospitalization, and as outpatients 1-2 months following hospital discharge. Pulmonary function values were adjusted for differences in body length and expressed as Z-scores. Upon admission flows were decreased, and FRC was increased in both groups; there were no differences between the groups. The change in pulmonary function from admission to Day 10 of hospitalization was not different for the two groups. From admission to outpatient follow-up after hospitalization, there was a significant increase in flows for the steroid group, but not for the placebo group. In addition, the direction of change in FRC was significantly different for the two groups; the steroid group had a small decrease in FRC, while the placebo group had a small increase in FRC. These findings suggest that the addition of intravenous hydrocortisone to the standard treatment of CF infants hospitalized for a LRI may produce a greater or a more sustained improvement in lung function following hospitalization.

Anti-Inflammatory Agents↗

PubMed1997

Trabecular bone volume and microdamage accumulation in the femoral heads of women with and without femoral neck fractures.

Repetitive loading causes fragility and microdamage accumulation in the skeleton, but it is not clear whether microcracks accumulate with age in the human skeleton, or whether older women with femoral neck fractures have more microdamage than older women without fracture. This study tested the hypotheses that: (1) microcracks accumulate in the femoral head with age; and (2) older women with femoral neck fractures have significantly more microcracks than similar aged women without fractures. Nonosteoarthritic femoral heads from 9 young (16-66 years) and 12 old (73-88 years) female cadavers and those from 7 females with femoral neck fractures (56-90 years) were dissected. Midfrontal slabs were block stained with 1% basic fuchsin and 150-microm-thick specimens were measured histomorphometrically. Percent trabecular bone area (TbxAr) significantly decreased in older and fractured subjects compared with young subjects (p < or = 0.05). Microcrack density (CrxDn) was significantly higher in women older than 70 years compared with those younger than 70 (p = 0.005; Spearman's r = 0.41, p = 0.032), but was not different between older women with and without fractures. Osteocyte lacunar density (OtxDn) was significantly less in old and fractured subjects compared with young subjects (p < or = 0.01), and inversely correlated to crack density (r = -0.49, p = 0.011). CrxDn was higher in women with low TbxAr (Spearman's r = -0.56; p = 0.004), and varied inversely with OtxDn (Spearman's r = -0.47; p = 0.014). This is consistent with the idea that cracks accumulate more rapidly in women with low bone density. It is also consistent with the idea that the osteocyte network detects microcracks, and signals for their repair.

Adolescent↗