Biomedical subjects

R Peters

Publications and source records attributed to R Peters.

At least 73 records · Page 4Linked to original sources

PubMed1999

Visualization of nuclear pore complex and its distribution by confocal laser scanning microscopy.

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3T3 Cells↗

PubMed1999

Multiple courses of high-dose ifosfamide, carboplatin, and etoposide with peripheral-blood progenitor cells and filgrastim for small-cell lung cancer: A feasibility study by the European Group for Blood and Marrow Transplantation.

PURPOSE: To determine the feasibility and safety of multiple sequential courses of high-dose chemotherapy and peripheral-blood progenitor cells (PBPCs) administered in a multicenter setting to patients with small-cell lung cancer. PATIENTS AND METHODS: Sixty-nine patients (limited disease, n = 30; extensive disease, n = 39) treated at 15 European centers were scheduled to receive three courses of high-dose chemotherapy with ifosfamide 10 g/m(2), carboplatin 1200 mg/m(2), and etoposide 1200 mg/m(2) (ICE) divided over 4 days at 28-day intervals. PBPCs were harvested before treatment and mobilized with epirubicin 150 mg/m(2) administered via an intravenous bolus divided over 2 days and filgrastim 5 microg/kg/d administered subcutaneously. RESULTS: The performed leukaphereses (one to five per patient) yielded a median of 16.6 x 10(6)/kg (range, 1.0 to 96.6 x 10(6)/kg) CD34(+) cells, which was sufficient for three reinfusions. Fifty patients (72%) completed the treatment according to schedule. Nine patients completed two courses, and six patients completed one course of treatment. The increase in dose-intensity was 290% that of a standard ICE regimen. The median duration of myelosuppression was similar between courses, namely 4 days (range, 1 to 12 days) for leukocytes less than 0.5 x 10(9)/L and 4 days (range, 0 to 22 days) for thrombocytes less than 20 x 10(9)/L. Febrile neutropenia developed in 66% of courses, severe diarrhea in 14%, mucositis in 10%, and nausea and vomiting in 21% of courses. There were six cases of toxic death (9%), most of which occurred in the first year of accrual and thus were attributable to the learning curve. The antitumor effect of the regimen was reflected in an 86% remission rate (95% confidence interval [CI], 74% to 93%), with 51% of patients achieving a complete response (95% CI, 38% to 63%). Median overall survival was 18 months for patients with limited disease and 11 months for patients with extensive disease. CONCLUSION: This multiple sequential high-dose ICE regimen could be safely administered on a multicenter basis to patients with small-cell lung cancer. The dose-intensity could be increased to 290% that of standard ICE regimen. The benefit of this approach is currently being tested in a randomized trial that aims to double the long-term rate of survival for patients with small-cell lung cancer.

Adult↗

PubMed1999

Carboxy-terminal conversion of profibrillin to fibrillin at a basic site by PACE/furin-like activity required for incorporation in the matrix.

Fibrillin-1, the main component of 10-12 nm microfibrils of the extracellular matrix, is synthesized as profibrillin and proteolytically processed to fibrillin. The putative cleavage site has been mapped to the carboxy-terminal domain of profibrillin-1, between amino acids arginine 2731 and serine 2732, by a spontaneous mutation in this recognition site that prevents profibrillin conversion. This site contains a basic amino acid recognition sequence (R-G-R-K-R-R) for proprotein convertases of the furin/PACE family. In this study, we use a mini-profibrillin protein to confirm the cleavage in the carboxy-terminal domain by both fibroblasts and recombinantly expressed furin/PACE, PACE4, PC1/3 and PC2. Site-directed mutagenesis of amino acids in the consensus recognition motif prevented conversion, thereby identifying the scissile bond and characterizing the basic amino acids required for cleavage. Using a PACE/furin inhibitor, we show that wild-type profibrillin is not incorporated into the extracellular matrix until it is converted to fibrillin. Therefore, profibrillin-1 is the first extracellular matrix protein to be shown to be a substrate for subtilisin-like proteases, and the conversion of profibrillin to fibrillin controls microfibrillogenesis through exclusion of uncleaved profibrillin.

Animals↗

PubMed1999

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality.

A stereogenic center at the position beta to the metallocene backbone is present in ferrocenyl ligands 2, which are interesting for asymmetric catalysis. These planar-chiral compounds are accessible for the first time by a highly diastereoselective and enantioselective synthesis (de=93-97 %; ee>/=96 %) from the ferrocenyl ketones 1. A variety of donor groups (E(1)=Ph(2)P small middle dotBH(3), SMe, SiPr; E(2)=SMe, STol, SePh, Ph(2)P small middle dotBH(3), iPr(2)P small middle dotBH(3)) can be introduced as electrophiles. Tol=tolyl=CH(3)C(6)H(4).

Journal Article↗

PubMed1999

Persistent hyperplastic primary vitreous with myopia: a case study.

BACKGROUND: Persistent hyperplastic primary vitreous (PHPV) is a congenital disorder that manifests a range of ocular anomalies, including leukocoria, microphthalmia, cataract, and a retrolental fibrovascular membrane. In general, the prognosis for visual acuity with PHPV has been poor. A recent report on six patients who have myopia associated with PHPV showed that these patients were not microphthalmic, did not manifest leukocoria, and showed a mean visual acuity at final followup of 20/160. CASE REPORT: The case of a 3-year-old boy with myopic PHPV of the left eye is presented. Full-time wear of the cycloplegic refraction, combined with patching of the non-amblyopic eye, resulted in an improvement in visual acuity. RESULTS: PHPV with myopia may constitute a distinct subtype of PHPV. Patients with myopic PHPV tend to seek treatment later than patients with anterior or posterior PHPV as a result of the lack of microphthalmia and leukocoria. These individuals do not show the long-term complications, such as secondary glaucoma and intraocular hemorrhages, associated with PHPV. CONCLUSION: The acuity improvement in this case of myopic PHPV suggests that a more conservative approach to its surgical management may be appropriate while pursuing refractive correction and amblyopia therapy to attain the best acuity possible.

Child, Preschool↗

PubMed1999

Low-molecular weight heparins in venous and arterial thrombotic disease.

INTRODUCTION: Since the introduction of low-molecular-weight heparins (LMWHs) in the early 1980's, the use of these compounds has been extensively investigated as a substitute for unfractionated heparin (UFH) in patients with venous and arterial thrombotic diseases. LMWHs have several advantages as compared to UFH, such as the subcutaneous route of administration, the predictable anticoagulant response and the lack of the need for laboratory monitoring. The present systematic review evaluates randomised clinical trials which investigated the efficacy and safety of LMWH in the acute treatment of venous thromboembolism, myocardial infarction, unstable coronary syndromes and ischemic stroke. METHODS: A computerised and manual search was performed to identify all relevant clinical trials. All randomised studies, with an a priori defined study population, clinical outcome measurement and adequate follow-up, were reviewed by two independent assessors. Whenever possible a common effect estimate of the included studies was calculated. RESULTS: Thirteen studies in approximately 4000 patients with acute venous thromboembolism revealed an odds ratio for the 3-month recurrent thromboembolism rate and major bleeding complications during exposure of 0.77 (C.I. 0.57-1.04) and 0.61 (C.I. 0.39-0.95), respectively, in favour of LMWH as compared to UFH. In patients with acute myocardial infarction, one study suggested a reduction in the incidence of reinfarction and cardiac death in LMWH recipients compared to UFH, while a placebo-controlled study revealed no beneficial effect of LMWH on these outcomes. In six studies including over 7000 patients with acute unstable coronary syndromes, there was an odds ratio for recurrent angina, myocardial infarction, urgent revascularisation and major bleedings of 0.88 (C.I. 0.76-1.01), 0.84 (C.I. 0.69-1.01), 0.83 (C.I. 0.70-0.99), 1.09 (C.I. 0.70-1.70), respectively, in favour of LMWH compared to UFH. The three studies comparing LMWH treatment with placebo in approximately 1000 patients with acute ischemic stroke revealed an odds ratio for the 10-day recurrent stroke, death or disability after 3 months and major bleeding complications of 0.68 (C.I. 0.41-1.13), 0.94 (C.I. 0.78-1.15), 2.92 (C.I. 1.88-4.55), respectively. CONCLUSION: Fixed-dose subcutaneous LMWH appears to be a safe and effective alternative for dose-adjusted intravenous heparin in the treatment of patients with acute venous thrombotic disease as well as in patients with acute unstable coronary syndromes. The effectiveness of LMWH in patients with acute myocardial infarction remains unclear. There seems to be no beneficial effect of LMWH treatment as compared to placebo in patients with acute ischemic stroke, while the risk of major bleeding was clearly increased.

Fibrinolytic Agents↗

PubMed1998