PubMed Health⌕ Search

Biomedical subjects

Peter Rehak

Publications and source records attributed to Peter Rehak.

41 records · Page 3Linked to original sources
PubMed2002

Comparison of 5-aminolaevulinic acid and porphyrin photosensitization for photodynamic therapy of malignant bronchial stenosis: a clinical pilot study.

BACKGROUND AND OBJECTIVES: Photosan, a mixture of porphyrin oligomers as sensitizer for photodynamic therapy (PDT), carry the risk of prolonged photosensitivity of the skin. New sensitizer such as 5-aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared to Photosan for PDT in malignant tracheo-bronchial stenosis. Reduction of tumor stenosis, increase in quality of life, and phototoxicity were considered as primary objectives. Improvement in clinical symptoms due to reduction of tumor stenosis, for example hemotysis, dyspnea, and poststenotic pneumonia were considered as secondary objectives. PATIENTS AND METHODS: After diagnostic work-up, photosensitization was done in 16 patients with ALA (60 mg/kg BW, oral, 6-8 hours prior to PDT) and in 24 patients with Photosan (2 mg/kg BW, i.v., 48 hours before PDT). The light dose was calculated as 100 J/cm(2) tumor length. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure. RESULTS: Stenosis diameter and Karnofsky performance status showed a significant improvement in favor of the Photosan-group, P = 0.00073 and 0.00015, respectively. In both groups no sunburn occurred due to phototoxicity of the sensitizer. CONCLUSION: Despite the limitations of a non-randomized study, photosensitization with Photosan seems to be more effective in PDT of malignant tracheo-bronchial stenosis compared to ALA.

Adenocarcinoma↗
PubMed2002

Hyperhomocyst(e)inemia and Chlamydia pneumoniae IgG seropositivity in patients with coronary artery disease.

Elevated levels of homocyst(e)ine and infection by Chlamydia pneumoniae have been hypothesized individually to play a role in coronary artery disease (CAD), but the mechanisms are unclear. Data on a possible association are not available. We investigated the correlation between IgG antibody titers against C. pneumoniae and fasting plasma homocyst(e)ine in 234 consecutive male patients with CAD. Chlamydial antibodies to a recombinant genus-specific lipopolysaccharide (LPS) were measured with ELISA. Total homocyst(e)ine (tHcy) concentrations were measured by high-performance liquid chromatography (HPLC). Thirty-seven subjects were classified hyperhomocyst(e)inemic (fasting homocyst(e)ine>14 micromol/l, group A), and 197 subjects were below cut-off (tHcy<14 micromol/l, group B). Prevalence of IgG seropositivity against C. pneumoniae was significantly higher in group A (68%) as compared to group B (39%, P=0.002). Antibody titers were also significantly higher in hyperhomocyst(e)inemic subjects than in cases with low homocyst(e)ine levels (P=0.002). Overall titers correlated significantly with tHcy levels (r(2)=0.222, P=0.001). Hyperhomocyst(e)inemia was associated with arterial hypertension (P=0.003), intake of lipid lowering drugs (P=0.022) and quite not with low folate concentration (P=0.052). No association was seen for IgG seropositivity or homocyst(e)ine and age, body mass index, smoking, diabetes, vitamin B(6) and B(12), cholesterol and triglycerides. These data indicate an association between elevated plasma homocyst(e)ine concentrations and chlamydial IgG antibody titers in patients with CAD.

Adult↗
PubMed2002

Urapidil reduces elevated pulmonary vascular resistance in patients before heart transplantation.

BACKGROUND: Elevated pulmonary vascular resistance is a major limitation for heart transplantation. Urapidil is a centrally and peripherally acting anti-hypertensive drug, able to decrease elevated pulmonary vascular resistance in patients with either chronic obstructive pulmonary disease or heart failure. Urapidil is available as an oral or intravenous drug. In this study, we evaluated the possible beneficial effects of intravenous urapidil in patients with reversible, elevated pulmonary vascular resistance who were scheduled for heart transplantation. METHODS: After approval by the Ethics Committee and written consent, 22 consecutive patients with end-stage heart failure and history of pulmonary vascular resistance >3 Wood units were enrolled into an open, prospective study. Using a (right ventricular ejection fraction) REF-Swan-Ganz catheter, hemodynamics were determined during administration of nitric oxide, and before and after 3 repeated intravenous applications of 10 mg urapidil. The treatment goal was reduction of pulmonary vascular resistance by at least 30%. RESULTS: Twenty-two patients were included to obtain complete data for 14 patients. Eight patients were not treated with urapidil: 7 patients had normal pulmonary vascular resistance at baseline, and 1 patient experienced moderate pulmonary edema before the study began. Two patients did not reach the treatment goal. In patients who responded to urapidil, the following hemodynamic changes were observed: decreased pulmonary vascular resistance (-48%), decreased transpulmonary gradient (20.0 to 13.7 mm Hg), decreased mean pulmonary arterial pressure (40 to 31 mm Hg), decreased systemic vascular resistance (-27%), mean arterial pressure (80 to 72 mm Hg), and increased right heart ejection fraction (21% to 27%). Heart rate remained unchanged. CONCLUSIONS: Intravenous urapidil lowered elevated pulmonary vascular resistance in patients before heart transplantation. In comparison with other vasodilative drugs, the major benefit of urapidil is its oral formulation.

Antihypertensive Agents↗
PubMed2002

Transesophageal echocardiography for quantifying size of patent foramen ovale in patients with cryptogenic cerebrovascular events.

BACKGROUND AND PURPOSE: Patent foramen ovale (PFO) is a risk factor for paradoxical embolism, and severe shunting and wide opening of PFO are risk factors for severe and recurrent cerebrovascular events. Neither contrast echocardiography nor 2-dimensional (2D) measurement of PFO size have been validated or compared with invasive balloon sizing. METHODS: We performed transesophageal echocardiography (TEE) in 100 patients with cryptogenic stroke and catheter closure of PFO. The amount of contrast shunting through the PFO during cubital and femoral contrast delivery and the PFO size measured by 2D TEE were compared with balloon sizing. RESULTS: There was a significant correlation (r(2)=0.8; P<0.0001) between 2D TEE measurement and invasive balloon sizing. Mean balloon-sized PFO diameter was significantly larger than mean PFO diameter measured by 2D TEE (8.3+/-2.6 versus 5.2+/-1.7 mm). Semiquantitative contrast TEE correlated with PFO size (r(2)=0.7; P<0.0001) only if the contrast agent was administered through a femoral vein. Correlation was poor when the contrast agent was administered via a cubital vein. CONCLUSIONS: We conclude that 2D TEE measurement of a PFO size is more accurate than the traditionally used contrast technique.

Adolescent↗