Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1440
    Keywords: Medullary thyroid carcinoma ; Prognostic factors ; Sporadic and familial form ; Age ; Sex ; Tumor stage at diagnosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A retrospective study of 741 patients with medullary thyroid carcinoma diagnosed between 1967 and 1991 was carried out by members of the German Medullary Thyroid Carcinoma Study Group to evaluate prognostic factors. A total of 559 patients (75%) were considered to have sporadic disease, and 182 (25%) had the familial type. The sex ratio (male to female) was 1:1.4 in sporadic disease patients, and the mean age at diagnosis was 45.9 years (range 5-81 years). For familial disease patients the sex ratio was 1:1.1, and the mean age at diagnosis was 33.4 (range 5–77 years). The follow-up time for 630 patients ranged from 1 month to 20.8 years (mean 13.0 years). The overall adjusted survival rate was 86.7% at 5 years and 64.2% at 10 years. In a univariate analysis the stage of disease at diagnosis, age, sex, and type of disease (sporadic, familial) were relevant prognostic factors, with a better prognosis for young female patients with familial disease and diagnosed at an early stage. In a multivariate proportional hazards analysis, the difference in the survival rate of patients with familial disease versus those with the sporadic form disappeared, while prognostic information provided by age and sex was still significant. The poorer prognosis of patients with sporadic medullary thyroid carcinoma may be related to the patients' older age at detection and more advanced tumor stage at diagnosis. There seems to be no difference in biological behavior between tumors of the sporadic and those of the familial type.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 54 (1994), S. 96-100 
    ISSN: 1432-0827
    Keywords: Bone ; Material quality ; Sound transmission ; Frequency of resonance ; Age ; Bone width
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In women before and after the age of peak bone mass, identical values of bone mineral density (BMD) can be obtained. However, there is a much higher incidence of osteoporotic fractures in older women. We investigated whether a deterioration of bone material quality with increasing age might contribute to this phenomenon. Material properties of bone tissue can be characterized by the modulus of elasticity, which is correlated to the square of sound transmission velocity. In this study, sound transmission velocity was determined in cortical bone by measuring the frequency of resonance in the ulna in the direction of the bone's longitudinal axis and correcting the values by multiplying by ulna length. Validation of this method indicated acceptable reproducibility: interobserver variability determined as the mean coefficient of variation was 1.82%. In a clinical study, 21 young women (22.5±1.2 years old) were compared with 21 middle-aged women (52.9±2.7 years old). Pairs were matched that had identical values of BMD in the nondominant forearm at a location representing mainly cortical bone (SPA). The product of ulna length and frequency of resonance in the ulna in the younger women was found to be 61.4±5.8 m/second, and in the middle-aged women 55.7±4.5 m/second. The difference was highly significant with P〈0.005. Our results confirm recent findings indicating a deterioration of bone material quality independent of BMD with increasing age. As shown by comparing ulna width at the site of measurement of bone mineral density between both groups of women, the deterioration of bone material quality in ulnar cortical bone with increasing age might at least in part be functionally compensated by an increase of the moment of inertia due to greater bone width [8, 10].
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1434-9949
    Keywords: Ultrasound ; Bone ; Material Quality ; Modulus of Elasticity ; Age ; Bone Mineral Density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influence the result. In humans APU was measured in the mediolateral direction at the midphalanx of the middle finger. In 53 healthy subjects (15–81 years old; 27 women, 26 men), there was a decrease of APU with age (r=−0.30, p〈0.05). Further, when comparing the results of both hands intraindividually almost identical values indicated constant intraindividual architecture of bone at this location. There was no evidence for a relation of APU to physical load comparing dominant and nondominant hand and relating the results to subjectively estimated physical load. In a second group of 43 perimenopausal women (47–60 years old), APU, which again decreased with age (r=−0.33, p〈0.05), was found not be correlated to BMD measured by SPA at the distal forearm (cortical bone). In a third group of 40 women (17–78 years old), APU again decreased with age (r=−0.60, p〈0.001) and was not correlated to BMD measured by SPA at the midphalanx of the middle finger, i.e. the same measuring location as APU. We conclude that this method provides information about the modulus of elasticity of bone with negligible influence of bone mineral density. Our results indicate that there is a deterioration of bone material quality with age independent of decreasing bone mineral density.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...