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Biomedical subjects

V Lindner

Publications and source records attributed to V Lindner.

At least 19 recordsLinked to original sources
PubMed2006

Inhibition of in-stent restenosis by oral copper chelation in porcine coronary arteries.

Stress-induced release of IL-1alpha and fibroblast growth factor-1 is dependent on intracellular copper and is a major driver of neointimal hyperplasia. Therefore, we assessed the effect of tetrathiomolybdate (TTM), a clinically proven copper chelator, on in-stent restenosis. Nine pigs were treated with TTM (5 mg/kg po) twice daily for 2 wk before stent implantation and for 4 wk thereafter, and nine pigs served as controls. In-stent restenosis was assessed by quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), and histomorphometry. Serum ceruloplasmin activity was used as a surrogate marker of copper bioavailability. In TTM-treated animals, ceruloplasmin dropped 70 +/- 10% below baseline levels. Baseline characteristics were comparable in TTM-treated and control animals. At 4-wk follow-up, all parameters relevant to in-stent restenosis were significantly reduced in TTM-treated animals: minimal lumen diameter by QCA was 2.03 +/- 0.57 and 1.47 +/- 0.45 mm in TTM-treated and control animals, respectively (P < 0.05), percent stenosis diameter was 39% less in TTM-treated animals (27.1 +/- 16.6% vs. 44.5 +/- 16.1%, P < 0.05), minimal lumen area by IVUS was 60% larger in TTM-treated animals (4.27 +/- 1.56 vs. 2.67 +/- 1.19 mm(2), P < 0.05), and neointimal volume by histomorphometry was 37% less in TTM-treated animals (34.9 +/- 11.5 vs. 55.2 +/- 19.6 mm(3), P < 0.05). We conclude that systemic copper chelation with a clinically approved chelator significantly inhibits in-stent restenosis.

Animals↗
PubMed2006

[Diffuse uptake of brown fat on computed-tomography coupled positron emission tomoscintigraphy (PET-CT) for the exploration of extra-adrenal pheochromocytoma].

We report an observation of strong bilateral uptake on a PET-CT scan compatible with activation of brown adipose tissue in a patient with extra-adrenal pheochromocytoma. A 42-year-old man was hospitalized for hypersudation together with weight loss and palpitations. Heart rate was 120 bpm and fasting blood glucose 1.36 g/l. Endocrine explorations revealed elevated serum chromogranine which reached 517 ng/ml (19-38). The norepinephrine level reached 49.7 nmol/l (<4.00) and urinary norepinephrine and normetanephrine levels reached 13977 nmol/24h (<414) and 32 micromol/24h (0.4-2.5) respectively. The thoraco-abdominal and pelvic scan showed a 6 cm diameter paraaortic hypervascularized mass with an infiltrative lesion of both perirenal area and mediastinal tissue without adenopathies. The abdominal MRI revealed the mass with a low intensity signal in T1 and a slight high intensity signal in T2. MIBG and octreoscan scintigraphies were negative. 18F-DG PET showed intensed uptake in the tumor mass together with intense, diffuse and bilateral uptake above and below the diaphragm. The mass was resected. Histological examination of the surgical specimen confirmed the diagnosis of extra-adrenal pheochromocytoma with an index of 13% cellular proliferation without cell atypia. There was a hypervascularization with small islets of brown adipose tissue in the perirenal fat. Both plasmatic and urinary catecholamines decreased to the normal range after the operation and PET-scan normalized. Bilateral spread of the radiotracer uptake was probably due to brown adipose tissue activation by excessive sympathetic stimulation induced by catecholamines released by the tumor.

Abdominal Neoplasms↗
PubMed2006

[Renal tumors].

This pictural essay presents the different imaging patterns of the main renal tumor processes described in the latest pathological classification. Most of them make it possible to suggest certain histological types in order to modify the surgical approach.

Adult↗
PubMed2005

Platelet activation and platelet-leucocyte interaction in patients with migraine. Subtype differences and influence of triptans.

As migraine is the result of an inflammatory mechanism with serotonergic signalling, leucocyte function, platelet function and intercellular communication between those cells is likely to be connected to the final pathway of the disease. We examined P-selectin expression on platelets (platelet activation) and leucocyte-platelet aggregate formation in 72 migraine patients during their attack-free interval and controls using a flow cytometric assay. Patients suffering from migraine without aura had a significantly increased platelet activation and leucocyte-platelet aggregation compared with the control group, unlike the migraine patients with aura. Patients who had taken a triptan within 3 days prior to the investigation showed platelet activation values similar to the control group. The variations in platelet activation patterns of migraine subgroups could indicate different pathomechanisms. Even outside an attack, migraine patients, particularly those without aura, show an increased level of platelet activation which seems to be down-regulated by triptans. This mechanism may account for the triptan-induced increases in headache frequency. The involvement of proinflammatory platelet-leucocyte cross-talk suggests a possible therapeutic strategy using anti-inflammatory drugs.

Female↗
PubMed2004

[Antidepressants and anticonvulsive agents. Practical utility profile in pain therapy].

Antidepressants are used in the treatment of neuropathic pain syndromes, as prophylaxis for primary headache syndromes, and in the treatment of fibromyalgia. Anticonvulsants are suited for therapy of all neuropathic pain syndromes, and can be applied as the method of second choice for certain headache syndromes. All substances tested with good results are tricyclic antidepressants. Their psychotropic action profile should be taken into consideration when planning therapy. Their antidepressive effect does not coincide with the effect of pain reduction. Therapy should start with a slow increase of the dose and can be prolonged as monotherapy or in combination with other analgetics. Carbamazepine is used in the treatment of shooting neuralgic pain attacks, whereas gabapentin has become the agent of first choice in the therapy of permanent neuropathic pain. Other substances in this group should be reserved for extraordinary situations based on their license and side effect profile.

Anticonvulsants↗
PubMed2001

CD44s and CD44v6 expression in localized T1-T2 conventional renal cell carcinomas.

To assess the prognostic value of CD44s and CD44v6 tumour expression for patients with T1-T2 conventional renal cell carcinomas, a retrospective immunohistochemical analysis of 95 patients was undertaken. These patients had undergone a radical nephrectomy, performed in three institutions in France between 1987 and 1993. The mean age of the patients was 62.9+/-10.2 years (range from 37 to 85 years) with 66.3% males. At the time of surgery, 84 patients had a T1 and 11 a T2 renal tumour. Fuhrman nuclear grading showed 44 (46.3%) tumours of grade 1, 39 (41.1%) of grade 2, and 12 (12.6%) of grade 3. The mean follow-up period was 58.1+/-36.1 months. At the end of follow-up, eight patients (8.4%) had metastatic disease and no local recurrence was seen. Immunohistochemistry showed that 26 tumours (27.4%) expressed CD44s, but none expressed CD44v6. Statistical analysis showed that CD44s expression was correlated with tumour size (p=0.006) and Fuhrman grading (p<10(-4)). Among the various parameters tested for the multivariate analysis, CD44s expression correlated only with disease-free survival (p=0.04). It is concluded that CD44s expression, but not CD44v6, is of potential prognostic interest in patients with localized T1-T2 conventional renal cell carcinomas.

Adult↗
PubMed2001

Vascular repair processes mediated by transforming growth factor-beta.

OBJECTIVES: The goal of this study was to determine the role of transforming growth factor-beta (TGF-beta) family members in arterial repair processes related to vascular injury. BACKGROUND: TGF-beta plays important roles in many tissues including calcifying tissues and blood vessels. The family members of TGF-beta 1, -beta 2, and -beta 3 have overlapping functions and signal via the same receptor complex. To examine the role of TGF-beta in vascular remodeling and intimal hyperplasia we disrupted this signaling pathway using recombinant soluble TGF-beta receptor II (TGF-beta R:Fc). METHODS: The balloon catheter injury model of the rat carotid artery was used and TGF-beta R:Fc was injected every other day for a period of two weeks after which the vessels were harvested for analysis by histology, morphometry, and Northern blotting. RESULTS: In situ hybridization showed TGF-beta receptor II expression in smooth muscle cells (SMC) of the injured vessel wall while the same cells also revealed abundant expression of all three TGF-beta ligands. Injection of TGF-beta R:Fc localized to the adventitia and developing neointima in the injured carotid artery, causing a reduction in intimal lesion formation (65%) and an increase in lumen area (88%). The increase in lumen area was largely due to inhibition of negative remodeling which coincided with reduced adventitial fibrosis and collagen synthesis. Four days after injury, TGF-beta R:Fc treatment almost completely inhibited the induction of smooth muscle alpha-actin expression in adventitial cells. CONCLUSIONS: These results identify TGF-beta isoforms as the major mediators of adventitial fibrosis and negative remodeling after arterial injury, which is a major cause for restenosis following angioplasty.

Animals↗
PubMed2001

Members of the Jagged/Notch gene families are expressed in injured arteries and regulate cell phenotype via alterations in cell matrix and cell-cell interaction.

The Jagged/Notch signaling pathways control cell fate determination and differentiation, and their dysfunction is associated with human pathologies involving cardiovascular abnormalities. To determine the presence of these genes during vascular response to injury, we analyzed expression of Jagged1, Jagged2, and Notch1 through 4 after balloon catheter denudation of the rat carotid artery. Although low levels of Jagged1, Jagged2, and constitutive expression of Notch1 were seen in uninjured endothelium, expression of all was significantly increased in injured vascular cells. High Jagged1 expression was restricted to the regenerating endothelial wound edge, whereas Notch transcripts were abundant in endothelial and smooth muscle cells. To understand the basis for Jagged/Notch control of cellular phenotype, we studied an in vitro model of NIH3T3 cells transfected with a secreted form of the extracellular domain of Jagged1. We report that the soluble Jagged1 protein caused decreased cell-matrix adhesion and cell migration defects. Cadherin-mediated intercellular junctions as well as focal adhesions were modified in soluble Jagged1 transfectants, demonstrating that cell-cell contacts and adhesion plaques may be targets of Jagged/Notch activity. We suggest that Jagged regulation of cell-cell and cell-matrix interactions may contribute to the control of cell migration in situations of tissue remodeling in vivo.

3T3 Cells↗
PubMed2001

A novel TNF receptor family member binds TWEAK and is implicated in angiogenesis.

TWEAK is a member of the TNF ligand family that induces angiogenesis in vivo. We report cloning of a receptor for TWEAK (TweakR) from a human umbilical vein endothelial cell (HUVEC) library. The mature form of TweakR has only one hundred and two amino acids and six cysteine residues in its extracellular region. Five different assays demonstrate TWEAK-TweakR binding, and the interaction affinity constant (Kd) is within a physiologically relevant range of 2.3 +/- 0.1 nM. The TweakR cytoplasmic domain binds TRAFs 1, 2, and 3. Cross-linking of TweakR induces HUVEC growth, and mRNA levels are upregulated in vitro by a variety of agents and in vivo following arterial injury. Soluble TweakR inhibits endothelial cell migration in vitro and corneal angiogenesis in vivo.

Amino Acid Sequence↗
PubMed2001

Efficacy and tolerability of rizatriptan 10 mg in migraine: experience with 70 527 patient episodes.

As patients who suffer from migraine need long-term treatment, the safety and consistent efficacy of such therapy is very important. Concurrent illness and additional medication can interfere with the treatment chosen for the attacks of migraine. The objective of this open-label study was to investigate the efficacy and tolerability of rizatriptan, in the treatment of up to three attacks of migraine, in the clinical setting. From October 1998 to July 1999, 6 174 doctors enrolled 33 147 patients into the study (26 644 women, 650 men). The mean age was 42.7 years. We were able to examine standardized migraine diaries relating to 25 501 patients and 70 537 migrainous episodes. Rizatriptan scored consistently high on efficacy and showed a consistently rapid onset. There was no evidence of tolerance to repeated use. An effect was reported within 1 hour of ingestion in 79% of attacks treated. In 27.8% of attacks, remission of headache was complete at 1 hour. Two hours after ingestion, 74% of attacks had subsided completely. Repeated administration of rizatriptan was well tolerated, and few adverse effects were seen. The most common unwanted effects were dizziness, weakness, fatigue, and nausea. No cardiovascular disturbance was seen. In the clinical setting, rizatriptan, 10 mg, is an effective and well-tolerated agent for the treatment of migraine attacks. Particularly noteworthy is the rapid onset of effect, with swift disappearance of headache. Rizatriptan has a favorable side effect profile, and, provided contraindications are observed, severe adverse cardiovascular complications are extremely unlikely.

Adult↗
PubMed2001

Developmental aspects of parathyroid hormone-related protein biology.

Parathyroid hormone-related protein (PTHrP) has been discovered as a parathyroid hormone (PTH)-like factor responsible for the humoral hypercalcaemia of malignancies. Further studies revealed that PTHrP is ubiquitously expressed, in mature as well as in developing normal tissues from various species. Although not completely understood, the biological roles of PTHrP concern a variety of domains, including calcium phosphorus metabolism and bone mineralization, smooth muscle relaxation, cell growth and differentiation, and embryonic development. As a poly-hormone, PTHrP is now acknowledged to act via the paracrine, autocrine, and even the intracrine pathways. This review focuses on the main developmental features of the biology of PTHrP. During embryonic development, PTHrP is considered to be involved as a growth factor that promotes cell proliferation and delays cell terminal maturation. PTHrP has been shown to intervene in the development of various tissues and organs such as the skeleton, skin, hair follicles, tooth, pancreas, and the kidney. In addition, through its midregion sequence, which is able to promote an active transplacental calcium transport, PTHrP may intervene indirectly in the mineralization of the foetal skeleton. PTHrP has also been shown to be necessary for the normal development of the mammary gland, while huge amounts of PTHrP are found in the human milk. Finally, observations of physiologic, vasodilating effects of PTHrP in the kidney suggest its involvment in the control of renal hemodynamics, especially in the perinatal period.

Animals↗
PubMed2001

Characterization of a mouse model for thrombomodulin deficiency.

Mutations in the gene encoding thrombomodulin (TM), a thrombin regulator, are suspected risk factors for venous and arterial thrombotic disease. We have previously described the generation of TM(Pro/Pro) mice carrying a TM gene mutation that disrupts the TM-dependent activation of protein C. Here, it is shown that inbred C57BL/6J TM(Pro/Pro) mice exhibit a hypercoagulable state and an increased susceptibility to thrombosis and sepsis. Platelet thrombus growth after FeCl(3)-induced acute endothelial injury was accelerated in mutant mice. Vascular stasis after permanent ligation of the carotid artery precipitated thrombosis in mutant but not in normal mice. Mutant mice showed increased mortality after exposure to high doses of endotoxin and demonstrated altered cytokine production in response to low-dose endotoxin. The severity of the hypercoagulable state and chronic microvascular thrombosis caused by the TM(Pro) mutation is profoundly influenced by mouse strain-specific genetic differences between C57BL/6 and 129SvPas mice. These data demonstrate that in mice, TM is a physiologically relevant regulator of platelet- and coagulation-driven large-vessel thrombosis and modifies the response to endotoxin-induced inflammation. The phenotypic penetrance of the TM(Pro) mutation is determined by as-yet-uncharacterized genetic modifiers of thrombosis other than TM.

Animals↗
PubMed2000

Evaluation of microsatellite analysis in urine sediment for diagnosis of bladder cancer.

Alterations at microsatellite DNA markers in cells exfoliated in urine have been correlated to the presence of bladder cancer. To check the feasibility of such noninvasive analysis to routinely diagnose bladder cancers, we have developed a highly sensitive method using fluorescent PCR to search for DNA microsatellite alterations in urine sediment compared with a blood paired sample. One hundred eighty-three patients were included in our study. This population comprised 103 bladder cancers (64 pTa stages), the complement representing controls and other benign or malignant diseases. Results of the analysis at 17 loci in a blinded study were compared with cystoscopy and/or pathology. The high reproducibility of this technique and the analysis of 26 control patients allowed us to determine for each microsatellite a cutoff characterizing a significant allelic imbalance. For bladder cancer detection, the overall sensitivity of the test was 84%. Using this procedure, we identified alterations in 81%, 84%, 91%, and 100% of pTa, pT1, pT2, and >pT2 stages, respectively. This corresponds to 79%, 82%, and 96% sensitivity for grades I, II, and III, respectively. Interestingly, for routine purposes, we observed an overall sensitivity of 80% (76% for pTa stages) when only the eight most rearranged microsatellites were considered. In conclusion, the noninvasive feature combined with the rapidity of this fluorescent and highly sensitive technique for the detection of early stages provides us with a useful help for the diagnosis of bladder cancer.

Adolescent↗
PubMed2000

Strain-dependent vascular remodeling phenotypes in inbred mice.

We have recently established a mouse model of arterial remodeling in which flow in the left common carotid artery of FVB mice was interrupted by ligation of the vessel near the carotid bifurcation, resulting in a dramatic reduction of the lumen as a consequence of a reduction in vessel diameter and intimal lesion formation. In the present study we applied this model to various inbred strains of mice. Wide variations in the remodeling response with regard to reduction in vessel diameter, intimal lesion formation, lumen area, and medial hypertrophy were found. On carotid artery ligation SJL/J mice revealed the most extensive inward remodeling leading to an approximate 78% decrease in lumen area while lumen narrowing in FVB/NJ mice was largely due to extensive neointima formation as a result of smooth muscle cell (SMC) proliferation. Significant positive remodeling in the contralateral right carotid artery with a >20% increase in lumen area was observed in SM/J and A/J mice. An in vitro comparison of growth properties of SMC isolated from FVB/NJ mice and a strain that exhibited very little SMC proliferation (C3H/HeJ) demonstrated accelerated growth of SMC from FVB/NJ following serum stimulation. In vivo, SMC proliferation in the FVB/NJ strain was preceded by a 37% loss of medial SMC occurring within the 2 days after ligation, however, cell death was not detectable in C3H/HeJ mice. These findings suggest that the mechanisms leading to lumen narrowing in the vascular remodeling process are genetically controlled.

Animals↗
PubMed2000

Alterations in expression of myosin and myosin light chain kinases in response to vascular injury.

Histochemical analysis of balloon-injured rat carotid arteries revealed a coordinated expression of nonmuscle myosin heavy chain-A and -B (NM-A and NM-B) in response to injury. Expression of these nonmuscle myosin forms shifts from the media to the adventitia and intima. In contrast, expression of smooth muscle myosin heavy chain-1 (SM-1) within the media is not altered, whereas smooth muscle myosin heavy chain-2 (SM-2) expression declines. Western blotting shows a statistically significant increase in expression of NM-A that occurs within 6 h in response to carotid injury, suggesting this myosin form may be an appropriate experimental marker for proliferating, migrating cells in injured vessels. No overall change in the relative expression level of NM-B was detected, suggesting that compensatory declines in media expression are balanced by increases in the intima and adventitia. Expression of SM-1 did not change in response to injury, whereas the expression of SM-2 significantly declined between 24 h and 7 days. Expression of myosin light chain kinase is also negatively regulated, and the decline in its expression parallels downregulation of SM-2.

Animals↗