Publications by authors named "Hanneke J M Meijer"

20 Publications

  • Page 1 of 1

The spatio-temporal distribution of archaeological and faunal finds at Liang Bua (Flores, Indonesia) in light of the revised chronology for Homo floresiensis.

J Hum Evol 2018 11 31;124:52-74. Epub 2018 Aug 31.

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Liang Bua, the type site of Homo floresiensis, is a limestone cave on the Indonesian island of Flores with sedimentary deposits currently known to range in age from about 190 thousand years (ka) ago to the present. Recent revision of the stratigraphy and chronology of this depositional sequence suggests that skeletal remains of H. floresiensis are between ∼100 and 60 ka old, while cultural evidence of this taxon occurs until ∼50 ka ago. Here we examine the compositions of the faunal communities and stone artifacts, by broad taxonomic groups and raw materials, throughout the ∼190 ka time interval preserved in the sequence. Major shifts are observed in both the faunal and stone artifact assemblages that reflect marked changes in paleoecology and hominin behavior, respectively. Our results suggest that H. floresiensis and Stegodon florensis insularis, along with giant marabou stork (Leptoptilos robustus) and vulture (Trigonoceps sp.), were likely extinct by ∼50 ka ago. Moreover, an abrupt and statistically significant shift in raw material preference due to an increased use of chert occurs ∼46 thousand calibrated radiocarbon (C) years before present (ka cal. BP), a pattern that continues through the subsequent stratigraphic sequence. If an increased preference for chert does, in fact, characterize Homo sapiens assemblages at Liang Bua, as previous studies have suggested (e.g., Moore et al., 2009), then the shift observed here suggests that modern humans arrived on Flores by ∼46 ka cal. BP, which would be the earliest cultural evidence of modern humans in Indonesia.
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http://dx.doi.org/10.1016/j.jhevol.2018.07.001DOI Listing
November 2018

Environmental dynamics during the onset of the Middle Stone Age in eastern Africa.

Science 2018 04 15;360(6384):86-90. Epub 2018 Mar 15.

Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.

Development of the African Middle Stone Age (MSA) before 300,000 years ago raises the question of how environmental change influenced the evolution of behaviors characteristic of early We used temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a markedly different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability. Aspects of Acheulean technology in this region imply that, as early as 615,000 years ago, greater stone material selectivity and wider resource procurement coincided with an increased pace of land-lake fluctuation, potentially anticipating the adaptability of MSA hominins.
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http://dx.doi.org/10.1126/science.aao2200DOI Listing
April 2018

Late Pleistocene songbirds of Liang Bua (Flores, Indonesia); the first fossil passerine fauna described from Wallacea.

PeerJ 2017 17;5:e3676. Epub 2017 Aug 17.

Ornithological Section, Senckenberg Research Institute, Frankfurt am Main, Germany.

Background: Passerines (Aves: Passeriformes) dominate modern terrestrial bird communities yet their fossil record is limited. Liang Bua is a large cave on the Indonesian island of Flores that preserves Late Pleistocene-Holocene deposits (∼190 ka to present day). Birds are the most diverse faunal group at Liang Bua and are present throughout the stratigraphic sequence.

Methods: We examined avian remains from the Late Pleistocene deposits of Sector XII, a 2 × 2 m area excavated to about 8.5 m depth. Although postcranial passerine remains are typically challenging to identify, we found several humeral characters particularly useful in discriminating between groups, and identified 89 skeletal elements of passerines.

Results: At least eight species from eight families are represented, including the Large-billed Crow ( cf. ) the Australasian Bushlark () a friarbird ( sp.), and the Pechora Pipit ( cf. )

Discussion: These remains constitute the first sample of fossil passerines described in Wallacea. Two of the taxa no longer occur on Flores today; a large sturnid (cf. ) and a grassbird ( sp.). Palaeoecologically, the songbird assemblage suggests open grassland and tall forests, which is consistent with conditions inferred from the non-passerine fauna at the site. cf. , found in the -bearing layers, was likely part of a scavenging guild that fed on carcasses of alongside vultures ( sp.), giant storks (), komodo dragons (), and probably as well.
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http://dx.doi.org/10.7717/peerj.3676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5563437PMC
August 2017

The extreme insular adaptation of Meijer, 2014: a giant Anseriformes of the Neogene of the Mediterranean Basin.

R Soc Open Sci 2017 Jan 11;4(1):160722. Epub 2017 Jan 11.

Department of Geology and Paleontology , Natural History Museum Vienna , Burgring 7, 1010 Vienna , Austria.

New skeletal elements of the recently described endemic giant anseriform Meijer, 2014 are presented, coming from the type-area of the Gargano and from Scontrone, southern and central Italy, respectively. The new remains represent the first bird remains found at Scontrone so far, and another shared element between these two localities, both part of the Apulia-Abruzzi Palaeobioprovince. The presence of a very reduced carpometacarpus confirms its flightlessness, only previously supposed on the basis of the very large size, while the morphologies of tarsometatarsus and posterior phalanges clearly indicate the adaptation of to a terrestrial, non-aquatic, lifestyle. Its very large body size is similar to that observed in different, heavily modified, insular waterfowl and has been normally interpreted as the response to the absence of terrestrial predators and a protection from the aerial ones. The presence of a carpal knob in the proximal carpometacarpus also indicates a fighting behaviour for this large terrestrial bird species.
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http://dx.doi.org/10.1098/rsos.160722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319340PMC
January 2017

Intranodal signal suppression in pelvic MR lymphography of prostate cancer patients: a quantitative comparison of ferumoxtran-10 and ferumoxytol.

PeerJ 2016 20;4:e2471. Epub 2016 Oct 20.

Department of Radiology and Nuclear Medicine, Radboudumc , Nijmegen , The Netherlands.

Objectives: The key to MR lymphography is suppression of T2* MR signal in normal lymph nodes, while retaining high signal in metastatic nodes. Our objective is to quantitatively compare the ability of ferumoxtran-10 and ferumoxytol to suppress the MR signal in normal pelvic lymph nodes.

Methods: In 2010, a set of consecutive patients who underwent intravenous MR Lymphography (MRL) were included. Signal suppression in normal lymph nodes in T2*-weighted images due to uptake of USPIO (Ultra-Small Superparamagnetic Particles of Iron Oxide) was quantified. Signal suppression by two USPIO contrast agents, ferumoxtran-10 and ferumoxytol was compared using Wilcoxon's signed rank test.

Results: Forty-four patients were included, of which all 44 had a ferumoxtran-10 MRL and 4 had additionally a ferumoxytol MRL. A total of 684 lymph nodes were identified in the images, of which 174 had been diagnosed as metastatic. USPIO-induced signal suppression in normal lymph nodes was significantly stronger in ferumoxtran-10 MRL than in ferumoxytol MRL ( < 0.005).

Conclusions: T2* signal suppression in normal pelvic lymph nodes is significantly stronger with ferumoxtran-10 than with ferumoxytol, which may affect diagnostic accuracy.
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http://dx.doi.org/10.7717/peerj.2471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5075689PMC
October 2016

Age and context of the oldest known hominin fossils from Flores.

Nature 2016 06;534(7606):249-53

Centre for Archaeological Science, School of Earth &Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Recent excavations at the early Middle Pleistocene site of Mata Menge in the So'a Basin of central Flores, Indonesia, have yielded hominin fossils attributed to a population ancestral to Late Pleistocene Homo floresiensis. Here we describe the age and context of the Mata Menge hominin specimens and associated archaeological findings. The fluvial sandstone layer from which the in situ fossils were excavated in 2014 was deposited in a small valley stream around 700 thousand years ago, as indicated by (40)Ar/(39)Ar and fission track dates on stratigraphically bracketing volcanic ash and pyroclastic density current deposits, in combination with coupled uranium-series and electron spin resonance dating of fossil teeth. Palaeoenvironmental data indicate a relatively dry climate in the So'a Basin during the early Middle Pleistocene, while various lines of evidence suggest the hominins inhabited a savannah-like open grassland habitat with a wetland component. The hominin fossils occur alongside the remains of an insular fauna and a simple stone technology that is markedly similar to that associated with Late Pleistocene H. floresiensis.
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http://dx.doi.org/10.1038/nature17663DOI Listing
June 2016

Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia.

Nature 2016 Apr 30;532(7599):366-9. Epub 2016 Mar 30.

Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts and remains of other extinct endemic fauna, were dated to between about 95 and 12 thousand calendar years (kyr) ago. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13-11 kyr cal. BP). Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago--potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans--is an open question.
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http://dx.doi.org/10.1038/nature17179DOI Listing
April 2016

The avian fossil record in Insular Southeast Asia and its implications for avian biogeography and palaeoecology.

PeerJ 2014 11;2:e295. Epub 2014 Mar 11.

Institut Català de Paleontologia Miquel Crusafont , Cerdanyola del Vallès , Spain.

Excavations and studies of existing collections during the last decades have significantly increased the abundance as well as the diversity of the avian fossil record for Insular Southeast Asia. The avian fossil record covers the Eocene through the Holocene, with the majority of bird fossils Pleistocene in age. Fossil bird skeletal remains represent at least 63 species in 54 genera and 27 families, and two ichnospecies are represented by fossil footprints. Birds of prey, owls and swiftlets are common elements. Extinctions seem to have been few, suggesting continuity of avian lineages since at least the Late Pleistocene, although some shifts in species ranges have occurred in response to climatic change. Similarities between the Late Pleistocene avifaunas of Flores and Java suggest a dispersal route across southern Sundaland. Late Pleistocene assemblages of Niah Cave (Borneo) and Liang Bua (Flores) support the rainforest refugium hypothesis in Southeast Asia as they indicate the persistence of forest cover, at least locally, throughout the Late Pleistocene and Holocene.
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http://dx.doi.org/10.7717/peerj.295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3961167PMC
April 2014

Lymphotropic nanoparticle-enhanced MRI in prostate cancer: value and therapeutic potential.

Curr Urol Rep 2014 Mar;15(3):389

Department of Radiology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands,

Nodal staging in prostate cancer is suboptimal both with respect to current imaging modalities and pelvic lymph node dissection, and thus other techniques are being explored. Lymphotropic nanoparticle-enhanced MRI, also called magnetic resonance lymphography (MRL), is a technique that has shown high sensitivity (65-92 %) and excellent specificity (93-98 %) in detecting prostate cancer lymph node metastases. This technique aids in the detection of metastases in non-enlarged small nodes. MRL has been useful in determining the location and pathways of spread in nodal chains. Knowledge of the location of lymph node involvement is important for decisions regarding appropriate therapeutic options, such as image-guided therapy.. A geographic miss in radiotherapy can be avoided with the use of MRL-guided focal therapy. This paper provides an overview of current literature, lessons learned, and new therapeutic options with nanoparticle-enhanced MRI.
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http://dx.doi.org/10.1007/s11934-013-0389-7DOI Listing
March 2014

A retrospective analysis of the prognosis of prostate cancer patients with lymph node involvement on MR lymphography: who might be cured.

Radiat Oncol 2013 Jul 30;8:190. Epub 2013 Jul 30.

Background: The prognosis of prostate cancer patients with lymph node metastases so small they can only be visualized by new imaging techniques as MR lymphography (MRL) is unknown. The purpose of this study was to investigate the prognosis of prostate cancer patients with non-enlarged metastatic lymph nodes on MRL and to identify a subgroup of MRL-positive patients who might be candidates for curative treatment.

Methods: The charts of 138 prostate cancer patients without enlarged lymph nodes on CT, in whom a pre-treatment MRL was performed were reviewed. Endpoints were distant metastases-free survival and overall survival. Relation between the following factors and outcome were investigated: T-stage, PSA value at diagnosis, Gleason score, diameter (short axis and long axis) of the largest MRL-positive lymph node, number of MRL-positive lymph nodes, the presence of extra-pelvic nodal disease, and the extent of resection of the positive lymph nodes. Kaplan-Meier analysis was performed to estimate the survival functions.

Results: Of the 138 patients, 24 (17%) had a positive MRL. Patients with a short axis of the largest positive lymph node of ≤8 mm had a significantly better 5-year distant metastases-free (79% vs 16%) and overall survival (81% vs 36%) than patients with larger positive lymph nodes. This also accounted for patients with a largest long axis of ≤10 mm (71% vs 20% and 73% vs 40%, respectively). Outcome was also better in patients in whom all positive lymph nodes had been resected.

Conclusion: A selection of MRL-positive patients with a good prognosis could be identified, consisting of patients with small positive lymph nodes. In these patients, cure might be pursued.
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http://dx.doi.org/10.1186/1748-717X-8-190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3737042PMC
July 2013

Individualized image-based lymph node irradiation for prostate cancer.

Nat Rev Urol 2013 Jul 28;10(7):376-85. Epub 2013 May 28.

Department of Radiation Oncology [875], Radboud University Nijmegen Medical Centre, P O Box 9101, 6500 HB Nijmegen, The Netherlands.

Controversy surrounds the benefit of whole pelvis radiotherapy (WPRT) over prostate-only radiotherapy (PORT) for intermediate-risk and high-risk patients with prostate cancer. In the PSA screening era, two large randomized trials as well as multiple retrospective studies comparing WPRT with PORT have been performed, albeit with contradictory results. Data regarding the use of WPRT in patients with biochemical recurrence after prostatectomy are scarce. As a consequence, the practice of WPRT varies worldwide. Advanced highly accurate imaging methods for the detection of lymph node metastases in patients with prostate cancer have been developed, such as PET, single photon emission computed tomography (SPECT), diffusion-weighted MRI and magnetic resonance lymphography (MRL). The use of these new imaging methods might improve nodal irradiation, as they can be used not only for selection of patients, but also for accurately determining the target volume to reduce geographical miss. Furthermore, these new techniques can enable dose escalation to involved lymph nodes.
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http://dx.doi.org/10.1038/nrurol.2013.111DOI Listing
July 2013

Geographical distribution of lymph node metastases on MR lymphography in prostate cancer patients.

Radiother Oncol 2013 Jan 27;106(1):59-63. Epub 2012 Nov 27.

Department of Radiation Oncology, Radbound University Nijmegen, Medical Centre, Nijmegen, The Netherlands.

Purpose: To investigate the pattern of lymph node spread on magnetic resonance lymphography (MRL) in prostate cancer patients and compare this pattern to the clinical target volume for elective pelvis irradiation as defined by the radiation therapy oncology group (RTOG-CTV).

Methods And Materials: The charts of 60 intermediate and high risk prostate cancer patients with non-enlarged positive lymph nodes on MRL were reviewed. Positive lymph nodes were assigned to a lymph node region according to the guidelines for delineation of the RTOG-CTV. Five lymph node regions outside this RTOG-CTV were defined: the para-aortal, proximal common iliac, pararectal, paravesical and inguinal region.

Results: Fifty-three percent of the patients had an MRL-positive lymph node in a lymph node region outside the RTOG-CTV. The most frequently involved aberrant sites were the proximal common iliac, the pararectal and para-aortal region, which were affected in 30%, 25% and 18% respectively.

Conclusion: More than half of the patients had an MRL-positive lymph node outside the RTOG-CTV. To reduce geographical miss while minimizing the toxicity of radiotherapy, image based definition of an individual target volume seems to be necessary.
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http://dx.doi.org/10.1016/j.radonc.2012.10.021DOI Listing
January 2013

Magnetic resonance lymphography findings in patients with biochemical recurrence after prostatectomy and the relation with the Stephenson nomogram.

Int J Radiat Oncol Biol Phys 2012 Dec 18;84(5):1186-91. Epub 2012 Apr 18.

Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.

Purpose: To estimate the occurrence of positive lymph nodes on magnetic resonance lymphography (MRL) in patients with a prostate-specific antigen (PSA) recurrence after prostatectomy and to investigate the relation between score on the Stephenson nomogram and lymph node involvement on MRL.

Methods And Materials: Sixty-five candidates for salvage radiation therapy were referred for an MRL to determine their lymph node status. Clinical and histopathologic features were recorded. For 49 patients, data were complete to calculate the Stephenson nomogram score. Receiver operating characteristic (ROC) analysis was performed to determine how well this nomogram related to the MRL result. Analysis was done for the whole group and separately for patients with a PSA <1.0 ng/mL to determine the situation in candidates for early salvage radiation therapy, and for patients without pathologic lymph nodes at initial lymph node dissection.

Results: MRL detected positive lymph nodes in 47 patients. ROC analysis for the Stephenson nomogram yielded an area under the curve (AUC) of 0.78 (95% confidence interval, 0.61-0.93). Of 29 patients with a PSA <1.0 ng/mL, 18 had a positive MRL. Of 37 patients without lymph node involvement at initial lymph node dissection, 25 had a positive MRL. ROC analysis for the Stephenson nomogram showed AUCs of 0.84 and 0.74, respectively, for these latter groups.

Conclusion: MRL detected positive lymph nodes in 72% of candidates for salvage radiation therapy, in 62% of candidates for early salvage radiation therapy, and in 68% of initially node-negative patients. The Stephenson nomogram showed a good correlation with the MRL result and may thus be useful for identifying patients with a PSA recurrence who are at high risk for lymph node involvement.
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http://dx.doi.org/10.1016/j.ijrobp.2012.02.039DOI Listing
December 2012

Value of PET/CT and MR lymphography in treatment of prostate cancer patients with lymph node metastases.

Int J Radiat Oncol Biol Phys 2012 Nov 13;84(3):712-8. Epub 2012 Mar 13.

Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.

Purpose: To determine the clinical value of two novel molecular imaging techniques: (11)C-choline positron emission tomography (PET)/computed tomography (CT) and ferumoxtran-10 enhanced magnetic resonance imaging (magnetic resonance lymphography [MRL]) for lymph node (LN) treatment in prostate cancer (PCa) patients. Therefore, we evaluated the ability of PET/CT and MRL to assess the number, size, and location of LN metastases in patients with primary or recurrent PCa.

Methods And Materials: A total of 29 patients underwent MRL and PET/CT for LN evaluation. The MRL and PET/CT data were analyzed independently. The number, size, and location of the LN metastases were determined. The location was described as within or outside the standard clinical target volume for elective pelvic irradiation as defined by the Radiation Therapy Oncology Group. Subsequently, the results from MRL and PET/CT were compared.

Results: Of the 738 LNs visible on MRL, 151 were positive in 23 of 29 patients. Of the 132 LNs visible on PET/CT, 34 were positive in 13 of 29 patients. MRL detected significantly more positive LNs (p < 0.001) in more patients than PET/CT (p = 0.002). The mean diameter of the detected suspicious LNs on MRL was significantly smaller than those detected by PET/CT, 4.9 mm and 8.4 mm, respectively (p < 0.0001). In 14 (61%) of 23 patients, suspicious LNs were found outside the clinical target volume with MRL and in 4 (31%) of 13 patients with PET/CT.

Conclusion: In patients with PCa, both molecular imaging techniques, MRL and (11)C-choline PET/CT, can detect LNs suspicious for metastasis, irrespective of the existing size and shape criteria for CT and conventional magnetic resonance imaging. On MRL and PET/CT, 61% and 31% of the suspicious LNs were located outside the conventional clinical target volume. Therefore, these techniques could help to individualize treatment selection and enable image-guided radiotherapy for patients with PCa LN metastases.
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http://dx.doi.org/10.1016/j.ijrobp.2011.12.093DOI Listing
November 2012

Dodo remains from an in situ context from Mare aux Songes, Mauritius.

Naturwissenschaften 2012 Mar 27;99(3):177-84. Epub 2012 Jan 27.

Division of Birds, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-70122, USA.

Since 2005, excavations at Mare aux Songes, Mauritius, have revealed the presence of a very rich, ∼4,200-year-old fossil bone bed including dodo (Raphus cucullatus) bones and bone fragments. The recently excavated dodo assemblage comprises at least 17 individuals and is characterised by the presence of small and fragile skeletal elements, a dominance of leg elements and an absence of juveniles. The hydrology of the area suggests that dodos, like many other species, were probably lured to Mare aux Songes by the presence of freshwater during times of drought. The most likely scenario for the origin of the fossil deposit is that animals became trapped in the sediment in repeated miring events, which would favour the conservation of hindlimbs. Such a scenario is fully in accordance with the taphonomic characteristics of the bone assemblage.
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http://dx.doi.org/10.1007/s00114-012-0882-8DOI Listing
March 2012

High occurrence of aberrant lymph node spread on magnetic resonance lymphography in prostate cancer patients with a biochemical recurrence after radical prostatectomy.

Int J Radiat Oncol Biol Phys 2012 Mar 2;82(4):1405-10. Epub 2011 Jun 2.

Department of Radiation Oncology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.

Purpose: To investigate the pattern of lymph node spread in prostate cancer patients with a biochemical recurrence after radical prostatectomy, eligible for salvage radiotherapy; and to determine whether the clinical target volume (CTV) for elective pelvic irradiation in the primary setting can be applied in the salvage setting for patients with (a high risk of) lymph node metastases.

Methods And Materials: The charts of 47 prostate cancer patients with PSA recurrence after prostatectomy who had positive lymph nodes on magnetic resonance lymphography (MRL) were reviewed. Positive lymph nodes were assigned to a lymph node region according to the guidelines of the Radiation Therapy Oncology Group (RTOG) for delineation of the CTV for pelvic irradiation (RTOG-CTV). We defined four lymph node regions for positive nodes outside this RTOG-CTV: the para-aortal, proximal common iliac, pararectal, and paravesical regions. They were referred to as aberrant lymph node regions. For each patient, clinical and pathologic features were recorded, and their association with aberrant lymph drainage was investigated. The distribution of positive lymph nodes was analyzed separately for patients with a prostate-specific antigen (PSA) <1.0 ng/mL.

Results: MRL detected positive aberrant lymph nodes in 37 patients (79%). In 20 patients (43%) a positive lymph node was found in the pararectal region. Higher PSA at the time of MRL was associated with the presence of positive lymph nodes in the para-aortic region (2.49 vs. 0.82 ng/mL; p = 0.007) and in the proximal common iliac region (1.95 vs. 0.59 ng/mL; p = 0.009). There were 18 patients with a PSA <1.0 ng/mL. Ten of these patients (61%) had at least one aberrant positive lymph node.

Conclusion: Seventy-nine percent of the PSA-recurrent patients had at least one aberrant positive lymph node. Application of the standard RTOG-CTV for pelvic irradiation in the salvage setting therefore seems to be inappropriate.
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http://dx.doi.org/10.1016/j.ijrobp.2011.04.054DOI Listing
March 2012

Magnetic resonance lymphography-guided selective high-dose lymph node irradiation in prostate cancer.

Int J Radiat Oncol Biol Phys 2012 Jan 13;82(1):175-83. Epub 2010 Nov 13.

Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.

Purpose: To demonstrate the feasibility of magnetic resonance lymphography (MRL) -guided delineation of a boost volume and an elective target volume for pelvic lymph node irradiation in patients with prostate cancer. The feasibility of irradiating these volumes with a high-dose boost to the MRL-positive lymph nodes in conjunction with irradiation of the prostate using intensity-modulated radiotherapy (IMRT) was also investigated.

Methods And Materials: In 4 prostate cancer patients with a high risk of lymph node involvement but no enlarged lymph nodes on CT and/or MRI, MRL detected pathological lymph nodes in the pelvis. These lymph nodes were identified and delineated on a radiotherapy planning CT to create a boost volume. Based on the location of the MRL-positive lymph nodes, the standard elective pelvic target volume was individualized. An IMRT plan with a simultaneous integrated boost (SIB) was created with dose prescriptions of 42 Gy to the pelvic target volume, a boost to 60 Gy to the MRL-positive lymph nodes, and 72 Gy to the prostate.

Results: All MRL-positive lymph nodes could be identified on the planning CT. This information could be used to delineate a boost volume and to individualize the pelvic target volume for elective irradiation. IMRT planning delivered highly acceptable radiotherapy plans with regard to the prescribed dose levels and the dose to the organs at risk (OARs).

Conclusion: MRL can be used to select patients with limited lymph node involvement for pelvic radiotherapy. MRL-guided delineation of a boost volume and an elective pelvic target volume for selective high-dose lymph node irradiation with IMRT is feasible. Whether this approach will result in improved outcome for these patients needs to be investigated in further clinical studies.
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http://dx.doi.org/10.1016/j.ijrobp.2010.09.023DOI Listing
January 2012

Myofascial force transmission also occurs between antagonistic muscles located within opposite compartments of the rat lower hind limb.

J Electromyogr Kinesiol 2007 Dec 23;17(6):690-7. Epub 2007 Mar 23.

Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands.

Force transmission via pathways other than myotendinous ones, is referred to as myofascial force transmission. The present study shows that myofascial force transmission occurs not only between adjacent synergistic muscles or antagonistic muscles in adjacent compartments, but also between most distant antagonistic muscles within a segment. Tibialis anterior (TA), extensor hallucis longus (EHL), extensor digitorum longus (EDL), peroneal muscles (PER) and triceps surae muscles of 7 male anaesthetised Wistar rats were attached to force transducers, while connective tissues at the muscle bellies were left fully intact. The TA+EHL-complex was made to exerted force at different lengths, but the other muscles were held at a constant muscle-tendon complex length. With increasing TA+EHL-complex length, active force of maximally activated EDL, PER and triceps surae decreased by maximally approximately 5%, approximately 32% and approximately 16%, respectively. These decreases are for the largest part explained by myofascial force transmission. Particularly the force decrease in triceps surae muscles is remarkable, because these muscles are located furthest away from the TA+EHL-complex. It is concluded that substantial extramuscular myofascial force transmission occurs between antagonistic muscles even if the length of the path between them is considerable.
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http://dx.doi.org/10.1016/j.jelekin.2007.02.004DOI Listing
December 2007

Myofascial force transmission between antagonistic rat lower limb muscles: effects of single muscle or muscle group lengthening.

J Electromyogr Kinesiol 2007 Dec 26;17(6):698-707. Epub 2007 Mar 26.

Instituut voor Fundamentele en Klinische Bewegingswetenschappen, Faculteit Bewegingswetenschappen, Vrije Universiteit, van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands.

Effects of lengthening of the whole group of anterior crural muscles (tibialis anterior and extensor hallucis longus muscles (TA+EHL) and extensor digitorum longus (EDL)) on myofascial interaction between synergistic EDL and TA+EHL muscles, and on myofascial force transmission between anterior crural and antagonistic peroneal muscles, were investigated. All muscles were either passive or maximally active. Peroneal muscles were kept at a constant muscle tendon complex length. Either EDL or all anterior crural muscles were lengthened so that effects of lengthening of TA+EHL could be analyzed. For both lengthening conditions, a significant difference in proximally and distally measured EDL passive and active forces, indicative of epimuscular myofascial force transmission, was present. However, added lengthening of TA+EHL significantly affected the magnitude of the active and passive load exerted on EDL. For the active condition, the direction of the epimuscular load on EDL was affected; at all muscle lengths a proximally directed load was exerted on EDL, which decreased at higher muscle lengths. Lengthening of anterior crural muscles caused a 26% decrease in peroneal active force. Extramuscular myofascial connections are thought to be the major contributor to the EDL proximo-distal active force difference. For antagonistic peroneal complex, the added distal lengthening of a synergistic muscle increases the effects of extramuscular myofascial force transmission.
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http://dx.doi.org/10.1016/j.jelekin.2007.02.006DOI Listing
December 2007

Intermuscular interaction between synergists in rat originates from both intermuscular and extramuscular myofascial force transmission.

Cells Tissues Organs 2005 ;181(1):38-50

Center for Human Movement Studies, School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA, USA.

The purpose of the present study is to investigate the origin of mechanical interactions between the rat extensor digitorum longus (EDL) muscle and the grouped tibialis anterior and extensor hallucis longus muscles (TA+EHL). The proximal and distal tendons of EDL as well as the tied distal tendons of TA+EHL were transected and connected to force transducers. Connective tissues at the muscle bellies of the anterior crural compartment were left intact. Supramaximal stimulation of the common peroneal nerve activated all muscles maximally and simultaneously. Length-isometric force characteristics of distal TA+EHL were assessed. Simultaneously, forces exerted at the proximal and distal tendons of EDL, kept at constant muscle-tendon complex length and position, were measured. Intermuscular interaction was tested in two conditions: (a) after full longitudinal compartmental fasciotomy, and (b) after blunt dissection of the intermuscular connective tissue linkages between EDL and TA+EHL. Note that in the latter condition, intermuscular myofascial pathways were eliminated. In the initial condition, lengthening TA+EHL by 12 mm increased proximal (by 0.14 N, i.e. 9.5%) and decreased distal EDL force (by 0.21 N, i.e. 11.8%), despite the fact that EDL muscle-tendon complex length was kept constant. Blunt dissection decreased TA+EHL and distal EDL forces at low TA+EHL lengths only, while proximal EDL force decreased for all TA+EHL lengths tested. The dissection caused no changes in the TA+EHL length effects on proximal EDL force. In contrast, the amplitude of change in the distal EDL force curve decreased significantly (by 39%) subsequent to blunt dissection. It is concluded that mechanical interaction between synergists originates from both intermuscular as well as extramuscular connective tissues. The highest contribution, however, should be ascribed to the extramuscular pathway.
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http://dx.doi.org/10.1159/000089967DOI Listing
March 2006