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- Johannsson, Gudmundur, 1960, et al.
(författare)
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Growth hormone and the acquisition of bone mass.
- 1997
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Ingår i: Hormone research. - 0301-0163. ; 48 Suppl 5, s. 72-7
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Forskningsöversikt (refereegranskat)abstract
- Bone remodelling is a continuous, closely coupled process of bone resorption followed by bone formation. This process is regulated by factors and hormones which include GH, IGF-I and gonadal steroids. GH deficiency in childhood results in short stature and delayed bone maturation and a reduced peak bone mass might account for reduced BMC and BMD. Possible pathophysiological mechanisms for reduced bone mass in both childhood- and adult-onset GH deficiency are discussed. GH treatment effects on bone metabolism include increased remodelling, with increases in BMC, BMD and bone area. Increases in BMC and BMD are delayed while these changes are incorporated into the skeleton. BMC increases to a greater extent than BMD. At a cellular level, GH and IGF-I have direct and indirect effects on osteoblast and osteoclast precursors and fully differentiated cells. Osteoblasts possess both oestrogen and androgen receptors and bone loss accelerates with the loss of gonadal function. There are gender differences in GH effects on bone. BMD is related to fracture risk in the hip and lumbar spine in women. GH treatment might decrease fracture risk at a level comparable to oestrogen or bisphosphonate treatment. Patients with the lowest BMD prior to treatment derive the greatest benefit from GH therapy.
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| 2. |
- Kiviranta, Ilkka, et al.
(författare)
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Effects of mechanical loading and immobilization on the articular cartilage
- 1997
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Ingår i: Bailliere's Clinical Orthopaedics. - 1074-8814. ; 2:1, s. 109-122
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Forskningsöversikt (refereegranskat)abstract
- Articular cartilage provides nearly frictionless surfaces for joint movemants and reduces contact pressures, protecting the underlying suchondral bone from excess stress. The unique properties of articular cartilage are based on the interaction of the main components of the extracellular matrix: proteoglycans (PGs), collagen and interstitial fluid. Animal experiments and in vitro studies demonstrate that one of the most important regulators of the extracellular matrix metabolism is mechanical loading acting on the joints. Unloading and immobilization leads to PG depletion and softening of articular cartilage, increasing the risk of permanent cartilage degeneration. Moderate running exercise and increased weight bearing increases cartilage thickness, PG concentration and improves biomechanical properties of articular cartilage. With further increase in training intensity this positive influence of exercise disappears and cartilage shows changes analogous to immobilization of the joint, i.e. PG depletion and softening of the tissue. In humans most epidemiological studies have failed to prove the connection between running training and cartilage degeneration, but there is evidence that sports activities exposing joints to impact loading might increase the risk of osteoarthrosis.
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| 3. |
- Rangert, B, et al.
(författare)
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Design, maintenance and biomechanical considerations in implant placement.
- 1997
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Ingår i: Dental update. - 0305-5000. ; 24:10, s. 416-20
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Forskningsöversikt (refereegranskat)abstract
- Successful treatment using implants involves careful consideration of fixture placement and prosthesis design if the biomechanical conditions are to be optimized. These parameters may be related to the implant/tissue interface at the individual fixture level, and thence to the relationship between the components of a prosthesis. The influence of the nature and magnitude of occlusal forces can also be significant and should be carefully assessed before placement.
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| 4. |
- Roos, J, et al.
(författare)
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An update on the clinical documentation on currently used bone anchored endosseous oral implants.
- 1997
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Ingår i: Dental update. - 0305-5000. ; 24:5, s. 194-200
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Forskningsöversikt (refereegranskat)abstract
- In order to achieve safe and predictable results with oral implant therapy, the clinician has to rely on the scientific documentation when choosing a particular implant system. This review condenses the relevant clinical documentation on currently used endosseous oral implant systems and may help in the process of choosing an implant system.
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| 5. |
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| 7. |
- Bjermer, Leif, et al.
(författare)
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Long-acting beta(2)-agonists: how are they used in an optimal way?
- 1997
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Ingår i: Respiratory Medicine. - 1532-3064. ; 91:10, s. 587-591
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Forskningsöversikt (refereegranskat)abstract
- Inhaled long-acting beta(2)-agonists are frequently used for the treatment of asthma. When introduced to the market, the drug was accompanied by a debate among physicians and scientists raising warnings against the use of beta(2)-agonists, leading to a risk of tachyphylaxis and worsening of asthma control. During recent years, much of these warnings have been counter proved and there has been a tendency to institute treatment with long-acting beta(2)-agonists somewhat earlier in the course than before. However, the exact place for long-acting beta(2)-agonists in the asthma treatment plans, still needs to be established. While beta(2)-agonists have been shown to have anti-inflammatory activity in vitro and after single allergen exposure, this effect seems to disappear with regular treatment. The same phenomena have been shown to protect against obstruction caused by metacholine inhalation or exercise. Although the protective effect diminishes or even disappears, no signs of rebound phenomena or increased susceptibility to provocative stimulus has been shown. Thus, in contrast to earlier reports after regular use of short-acting beta(2)-agonists, no signs of tachyphylaxis have been reported after use of long-acting beta(2)-agonists. Moreover, the bronchodilatatory effect seems to be fairly stable after regular treatment, even though some reports claims that this effect diminishes over time. The present article is a review of some data involved in this debate. The authors conclude that long-acting beta(2)-agonists are a valuable contribution to the asthma treatment repertoire. However, the drugs should be regarded as long-acting bronchodilatators, supplementing the use of inhaled corticosteroids. The rapid appearing tolerance towards allergen-induced and provoked bronchial obstruction prevents these drugs from being used as monotherapy; they should be used only in combination with sufficient anti-inflammatory treatment, i.e. inhaled corticosteroids.
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| 9. |
- Christensson, A, et al.
(författare)
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The significance of serpins in the regulation of proteases in the male genital tract
- 1997
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Ingår i: Advances in Experimental Medicine and Biology. - Boston, MA : Springer US. - 0065-2598. ; 425, s. 76-163
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Forskningsöversikt (refereegranskat)abstract
- The male genital tract is rich in proteases, delivered by the male accessory sex glands, that are delicately balanced in their action by serpins, non-serpin class protease inhibitors and other regulatory mechanisms. Still, the biological function of the serpins and their target enzymes in the male genital tract and possible involvement in the regulation of normal reproductive function mainly remains to be elucidated. However, it is important with careful control of the catalytic activity of serine proteases, in particular in the different extracellular compartments, where they may produce significant potential hazards for biological structures. Immunochemical measurements of the serine protease prostate-specific antigen (PSA) in serum have gained widespread use in the monitoring and detection of prostate cancer. Moreover, the rapidly growing body of data on the disease-related variations in the proportion of different forms of PSA in serum which relate to the covalent complex formation between the serpin α1-antichymotrypsin and PSA has significantly improved the diagnostic specificity in blood testing for early detection of prostate cancer.
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