Relevance of laser irradiance threshold in the induction of alkaline phosphatase in human osteoblast cultures.

Induction of matrix synthesis by low-level laser has been demonstrated extensively. However, the question of dose- or power intensity-dependency is under-investigated. To address this issue we chose human osteoblast cell cultures and measured their alkaline phosphatase (ALP) activity after laser irradiation. The cell cultures were irradiated periodically by 690 nm radiation via optical transmission fiber-based laser needles, reaching into the culture dishes. The osteoblasts showed no induction of ALP activity when we used a single laser needle stimulation with a laser irradiance of 51 mW/cm(2), an increase of approximately 43% at 102 mW/cm(2) irradiance (two needles per well) and a ninefold increase at 204 mW/cm(2) irradiance (four needles per well), leaving the temperature of the culture medium unaffected. We concluded that the osteoblastic response in ALP activity to a laser stimulus shows a logarithmic relationship, with a distinct threshold, rather than a linear dose-dependency. Secondly, the laser irradiance, rather than the dose, is relevant for the impact of the laser.

Acupuncture treatment improves nerve conduction in peripheral neuropathy.

The etiology of peripheral neuropathy (PN) often remains elusive resulting in a lack of objective therapeutic strategies. We conducted a pilot study to evaluate the therapeutic effect of acupuncture on PN as measured by changes in nerve conduction and assessment of subjective symptoms. One hundred and ninety-two consecutive patients with PN as diagnosed by nerve conduction studies (NCS) were evaluated over a period of 1 year. Of 47 patients who met the criteria for PN of undefined etiology, 21 patients received acupuncture therapy according to classical Chinese Medicine as defined by the Heidelberg Model, while 26 patients received the best medical care but no specific treatment for PN. Sixteen patients (76%) in the acupuncture group improved symptomatically and objectively as measured by NCS, while only four patients in the control group (15%) did so. Three patients in the acupuncture group (14%) showed no change and two patients an aggravation (10%), whereas in the control group seven showed no change (27%) and 15 an aggravation (58%). Importantly, subjective improvement was fully correlated with improvement in NCS in both groups. The data suggest that there is a positive effect of acupuncture on PN of undefined etiology as measured by objective parameters.

Localisation of protein Z in vascular lesions of patients with atherosclerosis.

BACKGROUND: The deposition of protein Z was investigated in atherosclerotic vascular lesions of patients with diabetes mellitus or atherosclerotic vascular disease without diabetes in comparison to controls. PATIENTS AND METHODS: Protein Z antigen was evidenced by immunohistochemistry in arteries of 5 healthy control patients, 11 diabetic patients with arterio-occlusive disease and 7 patients suffering from arterio-occlusive disease without diabetes. For immunohistochemistry, a commercially available antibody was taken as first antibody, and immunopositivity was evaluated independently by two investigators (J.G.; I.K.) as negative (0), positive (+) and strongly positive (++). The results were assessed by the Whitney-Mann-Wilcoxon test. RESULTS: Macrovascular endothelial cells were stained positive for protein Z in all arteries studied. Arteries of controls did not show significant immunopositivity in cells other than macrovascular endothelial cells, while the microvascular endothelial cells of control arteries were largely negative. The proliferating subendothelial space in atherosclerotic vascular lesions showed significant immunopositivity for protein Z. In contrast to control arteries, the microvascular endothelial cells of the proliferating areas stained positive. The staining pattern of the subendothelial space was similar in atherosclerotic vessels independent of the risk factor for atherosclerosis. Plaques were immunopositive for protein Z, too. CONCLUSIONS: Protein Z is present in atherosclerotic vascular lesions of diabetic and non-diabetic patients, but not in the subendothelial space and microvascular endothelial cells of healthy controls. Since protein Z-positivity was detected in microvascular endothelium as well as in extra-vascular deposits around plaques, it may play a role in the development of these lesions.

Receptors for advance glycation end-products (AGE) - expression by endothelial cells in non-diabetic uraemic patients.

BACKGROUND: Cellular actions of advanced glycation end-products (AGE) are mediated by a receptor for AGE (RAGE), a novel integral membrane protein. Immunohistochemical studies show only low-level RAGE antigen expression in endothelial cells. Design. It was the purposes of the study to compare expression of RAGE antigen by endothelial cells in non-diabetic uraemic patients (n=8) with non-uraemic controls (n=11). Samples of arterial tissue were obtained at the time of renal transplantation (in uraemic patients) and abdominal surgery (in controls). RAGE antigen was visualized using guinea-pig anti-RAGE IgG and PAP technique. RESULTS: Marked staining for RAGE was noted in endothelial cells, both arterial endothelium and endothelium of vasa vasorum of normoglycaemic uraemic patients, but was not demonstrable in endothelial cells of large arteries and only faintly expressed in vasa vasorum of non-uraemic individuals. CONCLUSION: Normal endothelial cells do not constitually express RAGE antigen; in contrast it is expressed by arterial and capillary endothelial cells of uraemic patients. The observation is of note in view of the putative role of AGE of causing atherosclerotic and non-atherosclerotic vascular lesions.

Intravenous somatic gene transfer with antisense tissue factor restores blood flow by reducing tumor necrosis factor-induced tissue factor expression and fibrin deposition in mouse meth-A sarcoma.

Fibrin is deposited on the endothelial cell surface in the vasculature of murine methylcholanthrene A-induced sarcomas after injection of tumor necrosis factor (TNF). Capillary endothelial cells of the tumor vascular bed become positive for tissue factor after TNF injection, based on immunocytochemistry and in situ hybridization. Intravascular clot formation was not dependent on tissue factor derived from tumor cells, since in vessels of tumors not expressing tissue factor, TNF also induced fibrin/fibrinogen deposition. However, the time course of fibrin/fibrinogen deposition after TNF differed in tumors expressing no, little, or greater amounts of tissue factor. Fibrin/fibrinogen deposition was more rapid in tumors in which the neoplastic cells expressed tissue factor than in tumors not expressing tissue factor. In the tumors not expressing tissue factor, activation of coagulation was dependent on TNF-induced synthesis of tissue factor by host cells, i.e., endothelium or monocytes/macrophages. Intravenous somatic gene transfer with tissue factor cDNA in the antisense orientation (but not sense or vector alone) reduced intravascular fibrin/fibrinogen deposition and restored blood flow to the tumor, showing that de novo tissue factor expression is central in TNF-induced activation of the coagulation mechanism.

Mechanism of the tumor necrosis factor alpha-mediated induction of endothelial tissue factor.

This study examines the regulation of the human tissue factor (TF) promotor in vitro and in vivo. Transient transfections were performed in bovine aortic endothelial cells to investigate the role of two fundamentally different AP-1 sites and a closely located NF-kappa B site in the human TF promoter. The NF-kappa B site is functionally active, since overexpression of NF-kappa B(p65) resulted in induction of TF mRNA and activity. Promoter analysis showed that NF-kappa B induction was dependent on the integrity of the region from base pair -188 to -181. Over-expression of Jun/Fos resulted in TF induction of transcription and protein/activity. Functional studies revealed that the proximal AP-1 site, but not the distal, was inducible by Jun/Fos heterodimers. The distal AP-1 site, which has a G-->A switch at position 4, was inductible by Jun homodimers. Electrophoretic mobility shift assays, using extracts of tumor necrosis factor alpha (TNF alpha)-stimulated bovine aortic endothelial cells, demonstrated TNF alpha-inducible binding to the proximal AP-1 site, comprising JunD/Fos heterodimers. At the distal AP-1 site, only minor induction of binding activity, characterized as proteins of the Jun and ATF family, was observed. Consistently, this site only marginally participates in TNF alpha induction. Functional studies with TF promotor plasmids confirmed that deletion of the proximal AP-1 or the NF-kappa B site decreased TNF alpha-mediated TF induction to a higher extend than loss of the distal AP-1 site. However, integrity of both AP-1 sites and the NF-kappa B site was required for optimal TNF alpha stimulation. The relevance of these in vitro data was confirmed in vivo in a mouse tumor model. Expression plasmids for a dominant negative Jun mutant or I-kappa B were packaged in liposomes. When either mutated Jun or I-kappa B were injected intravenously 48 h before TNF alpha, a reduction in TNF alpha-mediated TF expression in the tumor endothelial cells was observed. Simultaneously, fibrin/fibrinogen deposition decreased and free blood flow could be restored. Thus, TNF alpha-induced up-regulation of endothelial cell TF depends on a concerted action of members of the bZIP and NF-kappa B family.

Expression of receptors for advanced glycation end products in peripheral occlusive vascular disease.

The cellular interactions of advanced glycation end products (AGEs), which have been hypothesized to contribute to the development of vascular lesions, occur, at least in part, through their binding to a novel integral membrane protein, the receptor for AGEs (RAGE). Studies of human vascular segments show that endothelial RAGE expression at the antigen and mRNA level was variable and usually at low levels in samples from healthy individuals. In contrast, patients with a range of peripheral occlusive vascular diseases, with or without underlying diabetes, demonstrated prominent enhancement of endothelial RAGE expression. Smooth muscle cells and nerves in the vessel wall showed constitutively high levels of RAGE expression that were unchanged with aging (from 1 to 92 years) or by the presence of vascular disease. These data suggest that RAGE is likely to have ligands other than AGEs, and that multiple factors in addition to AGEs impact on its expression. Taken together, our findings suggest that RAGE may contribute to the pathogenesis of a range of vascular disorders.

Intracellular compartmentation of troponin T: release kinetics after global ischemia and calcium paradox in the isolated perfused rat heart.

The marked differences in troponin T serum concentrations observed in patients with reperfused and non-reperfused myocardial infarction may be due to a perfusion dependent wash-out of an unbound fraction of cardiac troponin T. To test the release kinetics of troponin T experimentally, the isolated rat heart (Langendorff preparation) was damaged either by the calcium paradox or by no-flow ischemia. Following membrane damage by the calcium paradox troponin T (TNT) showed the same release kinetics in the coronary effluent as the cytosolic markers creatine kinase (CK) or lactate dehydrogenase (LDH). Peak levels of troponin T (282 +/- 58 micrograms/l), CK (6754 +/- 1642 U/l), and LDH (5817 +/- 1730 U/l) occurred 5 min after onset of reperfusion with calcium containing buffers and returned to 9.9%, 1.3%, and 1% of their respective peak levels within 55 min of reperfusion. During reperfusion after no-flow ischemia different release kinetics were found for cytosolic enzymes and troponin T. After 60 min of ischemia, troponin T levels in the coronary effluent increased over the entire reperfusion period of 55 min, almost doubling the 5 min value (191%). In contrast, cardiac enzymes rapidly declined to 18% (CK) and 23% (LDH) of their respective 5 min values at the end of reperfusion. Light microscopy after reperfusion with carbon black revealed a complete and homogeneous reperfusion of Langendorff hearts after no-flow ischemia. Immunoblot analysis confirmed the release of an undegraded 39 kDa troponin T molecule, both after global ischemia and the calcium paradox. These data indicate that prolonged ischemia induces a continuous liberation of cardiac troponin T, most probably from disintegrating myofibres, whereas membrane damage leads almost exclusively to leakage of a functionally unbound troponin T pool. These findings may explain the biphasic serum concentration changes of cardiac troponin T in patients with reperfused myocardial infarction.

Expression of receptors for advanced glycosylated end-products in renal disease.

BACKGROUND: Advanced glycation endproducts (AGEs) are believed to mediate long-term complications in diabetes mellitus. In this context we studied the expression of the receptor for AGEs (RAGE) in the kidney of patients with a variety of different renal diseases. METHODS: RAGE was detected by immunocytochemistry in renal biopsies. We compared the staining for RAGE in nine patients with diabetic nephropathy, 20 with inflammatory and/or immune complex and 10 with non-inflammatory renal diseases. Normal renal tissue from seven patients with tumour nephrectomies served as controls. RESULTS: In controls the only cells expressing RAGE constitutively were interstitial cells and vascular smooth muscle cells (6/7), while distal tubular cells were rarely positive (1/7). Endothelial cells of arteries/arterioles, glomerular endothelial cells, podocytes, and capsular epithelial cells were consistently negative. In diabetic nephropathy, inflammatory and/or immune complex, and non-inflammatory renal diseases, all cell types mentioned above became positive for RAGE. Whilst the distribution of RAGE in the tissue was quite similar, staining intensity in inflammatory and/or immune complex diseases was higher than in diabetic nephropathy. CONCLUSION: RAGE induction in the kidney is not specific for diabetic nephropathy and occurs in other types of renal diseases as well.