bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of the Zygomatic Arch in the Statics of the Skull and Its Adaptive Shape
Authors: Witzel U. , Preuschoft H. , Sick H.
Published: August 2004

The zygomatic arch of mammals is usually considered a phylogenetic relic of the fenestrations of the skull roof which may be observed in morphological sequences of primitive vertebrate skulls. If this concept is correct, the element is comparable (though not homologous) to the jugal arches of diapsid reptiles. Two major questions then remain unanswered: why different elements are maintained in reptiles and mammals during evolution, and why the arches are maintained as relics of ancestral forms. It is tempting to respond to the latter question with a very simple answer, namely that the elements function in order to sustain mechanical stresses. In this paper, we raise the questions which quality of stresses occurs in a primate skull within the zygomatic arches and what relationship these stresses hold to the morphology of these bony elements. An answer has been sought by means of finite element stress analysis. We found that the zygomatic arch in primate skulls represents a structure which carries, under all biologically relevant conditions, either compressive or tensile stresses. In a very simple model of the human skull under bite forces, a strip of stresses occurs lateral to the orbits, which seems roughly comparable to the zygomatic arch. Once such a structure exists and is used as an insertion of adductor muscles, it will be exposed to bending stress in side view and in frontal view. Morphological details of the zygomatic arch (curvature, profile, suture) are well suited to sustain the evoked stresses by a minimum of material.
Functional Structure of the Skull in Hominoidea
Authors: Preuschoft H. , Witzel U.
Published: August 2004

Finite elements stress analysis (FESA) was used to investigate the flow of compressive forces which occur if a homogenous, three-dimensional body representing the skull is loaded by simulated bite forces against the tooth row. Model 1 represents the snout alone. Bite forces are applied simultaneously, but increase rearward. Stresses in the model concentrate along the anterior contour and the lower surface of the model, leaving unstressed a nasal opening and a wide naso-oral connection. Model 2 represents the facial region, as far as the temporomandibular joint. The orbits and the nasal cavity are assumed to be present a priori. Model 3 applies reactions to the bite forces in the temporal fossa, corresponding to the origins of the masticatory muscles. Regions of the model under compressive stress correspond closely to the arrangement of bony material in a hominoid skull. If only the stress-bearing finite elements on each section are combined, and the stress-free parts neglected, the resulting three-dimensional shape is surprisingly similar to a hominoid skull. If bite forces are applied to parts of the tooth row only, the stress patterns are lower, asymmetrical and do not spread into all regions that are stress-bearing in simultaneous biting on all teeth. In model 2, the highest stresses occur at the tooth roots and along the forehead on top of the nasal roof. There are no marked stress concentrations on top of the orbits. The resulting shape resembles that of an orang-utan. In model 3, the highest stresses also occur at the tooth roots, but the circles of force mostly close below the brain case, so that the stress concentration in the forehead region remains much less marked. In this model, however, the stress concentrations are very similar to hollow brow ridges. The entire resulting shape resembles that of gorilla or chimpanzee skulls. A typical gracile australopithecine skull (STS-5) also shows clear similarities to the patterns of stress flow in our models. Compared to our earlier study of the modern human skull, differences relate to: the relative length and width of the dental arcade, the relative size of the brain case and the position of the arcade relative to the brain case. It seems that these traits are the points of attack of selective pressures, while all other morphological details are simply consequences of stress flow.
Stresses Exerted in the Hindlimb Muscles of Common Chimpanzees (Pan troglodytes) during Bipedal Locomotion
Authors: Thorpe S.K.S. , Crompton R.H. , Wang W.J.
Published: August 2004

Recent studies have indicated that chimpanzee bipedality is mechanically inefficient and dynamically unlike that of humans, thus undermining the chimpanzee analogy for mechanical aspects of the early evolution of hominid bipedalism. This paper continues this theme by measuring the forces and stresses engendered by the muscles during bipedal locomotion, for an untrained chimpanzee and for data from chimpanzees which have been encouraged to walk bipedally, presented in the literature. Peak stresses in the triceps surae were lower for the untrained chimpanzee than for the trained subjects because during the late stance phase, when peak ankle moments occur, the centre of pressure of the ground reaction force on the foot of the untrained chimpanzee stayed close to the ankle joint. In contrast, for the trained subjects it moved closer to the toes, as in human bipedalism. Quadriceps and hip extensor stresses are approximately 30% larger for the untrained chimpanzee than for the trained subjects, because the trained chimpanzees walked with a more erect posture. These results may reflect the way in which muscles can develop in response to training, since research on humans has shown that muscle physiological cross-sectional area increases as a result of exercise, resulting in smaller stresses for a given muscle force. During a slow walk, untrained chimpanzees were found to exert far greater muscle stresses than humans do when running at moderate speed, particularly in the muscles that extend the hip, because of the bent-hip, bent-knee posture.
The Relationship between Speed, Contact Time and Peak Plantar Pressure in Terrestrial Walking of Bonobos
Authors: Vereecke Evie , D’Août Kristiaan , De Clercq Dirk , Van Elsacker Linda , Aerts Peter
Published: August 2004

The aim of this paper is twofold. Firstly, we investigate whether contact times, as recorded by pedobarographic systems during quadrupedal and bipedal walking of bonobos, can be used to reliably calculate actual velocities, by applying formulae based on lateral-view video recordings. Secondly, we investigate the effect of speed on peak plantar pressures during bipedal and quadrupedal walking of the bonobo. Data were obtained from 4 individuals from a group of bonobos at the Animal Park Planckendael. From our study, we can conclude that both walking speeds calculated from contact times and lower leg length or simply from recorded contact times are good estimators for walking speed, when direct observation of the latter is impossible. Further, it was found that effects of speed on peak plantar pressures and vertical forces are absent or at least subtle in comparison to a large variation in pressure patterns. In bonobos, the same pressure patterns are used at all walking speeds, and, in consequence, we do not expect major changes in foot function.
Automatic Monitoring of Primate Locomotor Behaviour Using Accelerometers
Authors: Sellers W.I. , Crompton R.H.
Published: August 2004

Accelerometry data were transmitted by a radio collar attached to a hand-reared red-ruffed lemur housed in a large indoor/outdoor enclosure at Chester Zoo. An observer simultaneously recorded locomotor behaviour using a manually operated event recorder. Both data streams were recorded directly to hard disk to ensure accurate synchrony. Leaps were modelled using a y = x 2 – x 3 formulation for the take-off acceleration, to link peak acceleration to leap distance. Cyclic locomotor modes were analysed using power spectra and the modal frequency used to estimate stride periodicity. Comparison of the dual data shows that leaping behaviour can be recorded reliably, and acceleration magnitude provides accurate predictions of the distance travelled. Cyclic activities were less well characterised, but calibration should permit travel distance estimations equalling or bettering those from conventional techniques.Introduction
Congenital Abdominal Wall Defects: An Update
Authors: Wilson R. Douglas , Johnson Mark P.
Published: August 2004

Objective: To review published peer-reviewed literature regarding abdominal wall defects including gastroschisis and omphalocele. Methods: Review of published peer-reviewed literature using Med Line 1985–2003 and textbooks. Results: Gastroschisis and omphalocele literature is reviewed using pathology, incidence and epidemiology, prenatal evaluation, pregnancy and delivery management, postnatal outcome and fetal therapy. Conclusion: Gastroschisis and omphalocele are common abdominal wall defects and have significant morbidity and mortality.
Risk of Mosaicism and Uniparental Disomy Associated with the Prenatal Diagnosis of a Non-Homologous Robertsonian Translocation Carrier
Authors: Bruyère H. , Wilson R.D. , Langlois S.
Published: August 2004

Objective: To estimate the fetal risk of uniparental disomy (UPD) associated with the presence of a Robertsonian translocation (RT) in a parent or in the fetus, to determine whether it is clinically indicated to test these pregnancies for UPD. Methods: Retrospective analysis of our Centre’s experience in testing prenatal specimens for UPD in cases of known familial RTs or fortuitous RT finding. In addition, all reports dealing with prenatal UPD testing in similar populations obtained from PUBMED and the 1995–2001 American Society of Human Genetics Meeting’s abstracts were assessed. Results: No case of UPD 14 or 15 was found among the 51 tests performed at our Centre. Meta-analysis identified one case of UPD13 out of 687 UPD studies, conducted in 400 prenatal diagnoses. The 95% confidence interval of the risk of UPD in the population studied (1 in 738) is 0.02–0.76%. In one report, trisomy mosaicism for one of the chromosomes involved in the translocation was found in 3 cases out of 169 (95% confidence interval: 0.1–3 %). Conclusions: Fetuses carrying a Robertsonian translocation have a risk of UPD of 0.02–0.76% (95% CI). In this population, trisomy mosaicism is more frequent than UPD. This finding justifies the study of additional colonies in all cases of prenatally diagnosed RT.
HLA-G Antigen and Parturition: Maternal Serum, Fetal Serum and Amniotic Fluid Levels during Pregnancy
Authors: Hackmon Rinat , Hallak Mordechai , Krup Margalit , Weitzman Dahlia , Sheiner Eyal , Kaplan Boris , Weinstein Yacob
Published: August 2004

Objective: To determine whether soluble HLA-G1 (sHLA-G1) concentrations in maternal serum and in amniotic fluid are lower at term than in the second trimester. Methods: In this prospective study amniotic fluid and maternal serum samples were aspirated from 21 pregnant women during genetic amniocentesis at 16–20 weeks’ gestation, and from 19 women undergoing a cesarean section at term. In the latter group arterial umbilical cord blood was aspirated as well. sHLA-G1 levels were determined using ELISA assay. This assay included the anti-HLA-G monoclonal antibodies 87G and 16G1, both as capture antibodies and horseradish-peroxidase-labeled rabbit anti-human β2-microglobulin antibodies, as the detection antibody. The relative concentrations of sHLA-G1 were measured from the absorbancy of the blue product at 650 nm. Student’s t test was used for statistical analysis. Results: sHLA-G1 levels in amniotic fluid were significantly lower at term than in the second trimester (0.160 ± 0.05 vs. 0.272 ± 0.150 OD units; p < 0.05). Levels of sHLA-G1 in maternal serum declined toward term, but the difference from the second trimester was not statistically significant (0.266 ± 0.157 vs. 0.205 ± 0.120 OD units; p = 0.193). There was a strong correlation of sHLA-G1 concentrations between cord serum and maternal serum (R2 = 0.79; p < 0.001), but not between cord serum and amniotic fluid (R2 = 0.00004) or amniotic fluid and maternal serum (R2 = 0.02). Conclusions: sHLA-G1 antigen expression is higher in amniotic fluid than in maternal-fetal compartments and significantly decreases toward term. We speculate that the declining amniotic fluid sHLA-G1 levels may stimulate a maternal immunological response against the fetus and contribute to the initiation of parturition.
Spontaneous Regression and Reaccumulation of Pleural Effusion in a Fetus
Authors: Tarim Ebru , Oguzkurt Pelin , Kilicdag Esra , Bağis Tayfun , Erkanli Serkan , Aslan Erdogan , Lembet Arda
Published: August 2004

Isolated pleural effusion is rare and occurs when varying degrees of fluid surround the fetal lung without concomitant hydrops. The effusion may regress spontaneously, remain stable in size, or progress to involve both sides of the chest causing fetal hydrops. This may result in pulmonary hypoplasia and fetal or neonatal demise. In this article, we report a case in which spontaneous resolution of an isolated right-sided fetal pleural effusion occurred at 23 weeks of gestation and reappeared bilaterally at 34 weeks. Serial ultrasonographic evaluation of the fetus should be continued even if a spontaneous resolution of a preexisting pleural effusion has occurred.
Thoracoamniotic Shunts: Fetal Treatment of Pleural Effusions and Congenital Cystic Adenomatoid Malformations
Authors: Wilson R. Douglas , Baxter Jason K. , Johnson Mark P. , King Mary , Kasperski Stefanie , Crombleholme Timothy M. , Flake Alan W. , Hedrick Holly L. , Howell Lori J. , Adzick N. Scott
Published: August 2004

Objective: To determine whether fetuses that underwent thoracoamniotic shunt placement for treatment of pleural effusion (PE) or macrocystic congenital cystic adenomatoid malformation (CCAM) have an improved outcome as compared with an untreated population. Methods: A retrospective review from a single tertiary center was performed using thoracoamniotic shunt placement to treat PE or macrocystic CCAM between 1998 and 2001. Thoracoamniotic shunts were used on 26 occasions in 19 pregnancies. Results: The average gestational age at the diagnosis of PE and CCAM was 22 + 4 and 20 + 0 weeks, respectively. Shunts were offered in pregnancies complicated by hydrops or at significant risk for pulmonary hypoplasia. Shunts were placed at 26 + 2 weeks (average) and 23 + 1 weeks (average) in the PE and CCAM groups, respectively. In CCAM patients, the mean pre- and postshunting mass volumes were 50.5 and 25.7 cm3, representing a 51% reduction in mass volume following shunt placement. In the PE group, the average delivery age was 33 + 5 weeks, with an average shunt placement to delivery time of 7 + 3 weeks. In the CCAM group, the average delivery was 33 + 3 weeks, with an average shunt placement to delivery time of 10 + 2 weeks. The postnatal survival rates were 67% (6/9) and 70% (7/10) in the PE and CCAM groups, respectively. Conclusions: (1) Thoracoamniotic shunts should be considered as a treatment option for selected PE or macrocystic CCAM fetuses with hydrops or a significant risk for pulmonary hypoplasia; (2) the neonatal survival with shunting was similar for PE and CCAM groups and was improved as compared with literature reports, and (3) fetuses with CCAM presented earlier with hydrops than those with PE. Successful shunting resulted in a prolongation of pregnancy into the 3rd trimester in both groups.
Prenatal Sonographic Patterns in Six Cases of Wolf-Hirschhorn (4p–) Syndrome
Authors: Boog Georges , Le Vaillant Claudine , Collet Michel , Dupré Pierre François , Parent Philippe , Bongain André , Benoit Bernard , Trastour Claire
Published: August 2004

This multicentric study presents 6 cases of Wolf-Hirschhorn syndrome (deletion of 4p) detected after a sonographic prenatal diagnosis of early intrauterine growth retardation with fetal abnormalities. Standard karyotyping on regular G-banding during pregnancy was normal in half of the cases. Fortunately, the associated sonographic signs of a typical face, cystic cerebral lesions, midline fusion defects and bilateral renal hypoplasia may help to refine specific indications for high-resolution banding and molecular analysis by in situ hybridization.
Epinephrine Affects Hemodynamics of Noninnervated Normal and All-Trans Retinoic Acid-Treated Embryonic Chick Hearts
Authors: Kroese Jeanne Margot , Broekhuizen Monique L.A. , Poelmann Rob E. , Mulder Paul G.H. , Wladimiroff Juriy W.
Published: August 2004

Objective: To study the acute effect of epinephrine on hemodynamics of noninnervated normal and retinoic-acid-treated embryos. Design: Prospective interventional study design. Methods: A total of 190 stage 15 (50–55 h of incubation) chick embryos were randomly treated with 1 µg all-trans retinoic acid and reincubated. At stage 20 (day 3) and stage 24 (day 4), dorsal aortic flow velocities were measured with a 20-MHz pulsed Doppler velocity meter, in normal and retinoic-acid-treated embryos. Flow velocity waveforms were assessed both before and after the administration of epinephrine (5 or 10 µg). Results: Epinephrine caused a significant increase (p < 0.05) in heart rate, peak and mean velocities, peak acceleration, peak and mean blood flows, stroke volume and dorsal aortic area of both stage 20 and stage 24 normal and retinoic-acid-treated chick embryos. However, before epinephrine administration, stage 24 retinoic-acid-treated embryos displayed a significantly lesser increase in all outcome variables with the exception of dorsal aortic area. This was even observed after epinephrine administration. The effect of retinoic acid on cardiac output could not be compensated by epinephrine application. Conclusion: Epinephrine affects hemodynamics in both normal embryos and retinoic-acid-treated embryos prior to sympathetic innervation. A significant difference in hemodynamics exists between stage 24 normal and retinoic-acid-treated embryos. The underlying mechanism for the observed hemodynamic changes will need to be investigated.
Anomalies of the Fetal Venous System: A Report of 26 Cases and Review of the Literature
Authors: Viora E. , Sciarrone A. , Bastonero S. , Errante G. , Mortara G. , Chiappa E. , Campogrande M.
Published: August 2004

Objective: To evaluate sonographic appearance, natural history, and neonatal outcome of fetal venous anomalies. Methods: We performed an observational study, including all fetuses affected by abnormalities of the venous system diagnosed by ultrasound during the prenatal period. Results: 26 fetuses were identified. Other malformations were present in 5 cases (19.2%), 1 fetus had trisomy 21, and 1 fetus had intrauterine growth retardation (IUGR). Twenty-five pregnancies ended in liveborn infants, and there was 1 case of unexplained intrauterine death in the fetus with IUGR affected by varix of the umbilical vein. Conclusions: Fetal venous anomalies are very rare and may be associated with fetal malformations or IUGR. Conservative management appears to be an adequate medical practice in the absence of other fetal problems, but in the presence of a varix of the umbilical vein, serial follow-up scans are needed to exclude the onset of hydrops or thrombosis of the varix.
Intrafetal Alcohol Chemosclerosis of Acardiac Twins: A Multicenter Experience
Authors: Sepulveda Waldo , Corral Edgardo , Aiello Horacio , Otaño Lucas , Paredes Ricardo , Escobar Maria F. , Heredia Fernando , Quiroz Victor
Published: August 2004

Objective: To report a multicenter experience with intrafetal alcohol chemosclerosis in the treatment of pregnancies complicated with the twin reversed arterial perfusion sequence. Methods: Percutaneous injection of 1– 2 ml of absolute alcohol into the intra-abdominal segment of the single umbilical artery was performed in 8 acardiac twins. Cases were collected from 5 centers following a standardized protocol. The procedure was performed under continuous ultrasound control, using color Doppler ultrasound to identify the main arterial vessel entering the abdomen of the acardiac twin and passing a 20-gauge spinal needle into the targeted vessel. Intraoperative and short-term complications were noted. Information on pregnancy outcome was obtained by reviewing the medical records or contacting the referring obstetrician. Result: At the time of the procedure, the acardiac twin was severely hydropic and the size exceeded 70% of the size of the pump twin in all cases. In addition, there were associated complications in all the pump twins including polyhydramnios in 8 cases (100%), cardiac insufficiency in 5 (63%), and fetal growth restriction in 1 (13%). The procedure was performed at a mean gestational age of 24.7 weeks (range 20–32), and it was technically successful in all cases. However, it was complicated with thrombosis of the umbilical vessels of the pump twin in 1 case, and transient bradycardia in 2 others. These 3 pump twins died in utero as a result of the procedure. The other 5 procedures were technically and clinically successful, resulting in an overall survival rate of 63%. In 4 pregnancies, the pump twin was delivered after 35 weeks and had no neonatal complications. Conclusions: Intrafetal alcohol chemosclerosis is a simple procedure that can be performed in any fetal medicine center around the world to stop the vascular supply to acardiac twins. However, the main concern with this technique is intravascular transfer of the ablative material to the circulation of the pump twin. The use of this technique should therefore be restricted to those pregnancies with poor prognostic factors and in countries where more sophisticated methods for the treatment of this condition are not available.
Mediastinal Fetus in fetu
Authors: Beaudoin S. , Gouizi G. , Mezzine S. , Wann A.R. , Barbet P.
Published: August 2004

Fetus in fetu is an extremely rare condition defined by the presence of both axial skeleton and organoid formations in the parasitic mass. Besides some authors assuming that fetus in fetu and highly-differentiated teratomas are part of the same pathogenic spectrum, it has been emphasized that these criteria indicate a rather different embryogenetic mechanism. We herein report the first case to our knowledge developed in the ventral mediastinum that was thought to be a tumor before birth. The literature is reviewed and we propose a new explanation for the development of this rare anomaly, based on a defective implantation.
Low Pregnancy-Associated Plasma Protein-A at 10+1 to 14+6 Weeks of Gestation and a Possible Mechanism Leading to Miscarriage
Authors: Santolaya-Forgas J. , De Leon J.A. , Cullen Hopkins R. , Castracane V.D. , Kauffman R.P. , Sifuentes G.A.
Published: August 2004

Objective: To compare pregnancy-associated plasma protein-A (PAPP-A) serum levels at 10+1 to 14+6 weeks gestation in groups of patients with different obstetrical outcomes. Patients and Methods: The medical records of women who had consented to donate blood for biochemical research purposes while their pregnancies were uncomplicated were reviewed to define the clinical groups. After the clinical groups were defined, the donated maternal serum samples were thawed and PAPP-A measured by ELISA. ANOVA was used to compare mean values within groups. Result: All groups had similar gestational ages at blood donation (overall mean 12.5 weeks; no difference in gestational age was found within groups, p = 0.18). The overall PAPP-A serum level was 2.01 mIU/ml with only the spontaneous abortion group having a statistical different PAPP-A level (0.09 mIU/ml; p < 0.001). Conclusion: These data suggest that those women who experienced spontaneous abortions had significantly different mean PAPP-A serum levels at 10+1 to 14+6 weeks gestation. Several lines of evidence suggest that downregulation of insulin-like growth factor-II availability due to a decreased PAPP-A serum level may be the cause of spontaneous abortion in these women.
Suitability of a CMV/EGFP cassette to monitor stable expression from human artificial chromosomes but not transient transfer in the cells forming viable clones
Authors: Laner A. , Schwarz T. , Christan S. , Schindelhauer D.
Published: August 2004

Human artificial chromosomes (HACs) were generated by transfer of telomerized PAC constructs containing alpha satellite DNA of various human chromosomes. To monitor which cells took up constructs and subsequently formed stable clones under blasticidin S (BS) selection, a CMV/EGFP expression cassette was inserted into a HAC construct based on chromosome 5 alpha satellite DNA (142 kb). Lipofection into HT1080 cells resulted in a small proportion of cells exhibiting bright green fluorescence on day 1. Areas containing such early green cells were marked, and plates monitored over 2 weeks. In only one out of 41 marked areas, a viable clone developed. In the remaining 40 areas, the green cells ceased division at 1–8 cells. In contrast, outside the marked areas, 16 stable clones formed which did not exhibit green fluorescence during the first cell divisions, but all cells of each became green around day 4–6. Fluorescence in situ hybridization (FISH) analysis of isolated clonal lines demonstrated low copy HAC formation without integration. We conclude that transient expression of an EGFP marker on HAC DNA is not a suitable means for the identification of the proportion of transfected cells which are capable of forming viable clones. One explanation could be that the high copy number required to consistently detect transient EGFP expression (Schindelhauer and Laner, 2002) impairs viability and clone formation.
Strand-specific fluorescence in situ hybridization: the CO-FISH family
Authors: Bailey S.M. , Goodwin E.H. , Cornforth M.N.
Published: August 2004

The ability to prepare single-stranded chromosomal target DNA allows innovative uses of FISH technology for studies of chromosome organization. Standard FISH methodologies require functionally single-stranded DNAs in order to facilitate hybridization between the probe and the complementary chromosomal target sequence. This usually involves denaturation of double-stranded probes to induce temporary separation of the DNA strands. Strand-specific FISH (CO-FISH; Chromosome Orientation-FISH) involves selective removal of newly replicated strands from DNA of metaphase chromosomes which results in single-stranded target DNA. When single-stranded probes are then hybridized to such targets, the resulting strand-specific hybridization is capable of revealing a level of information previously unattainable at the cytogenetic level. Mammalian telomeric DNA consists of tandem repeats of the (TTAGGG) sequence, oriented 5′→3′ towards the termini of all vertebrate chromosomes. Based on this conserved structural organization, CO-FISH with a telomere probe reveals the absolute 5′→3′ orientation of DNA sequences with respect to the pter→qter direction of chromosomes. Development and various applications of CO-FISH will be discussed: detection of cryptic inversions, discrimination between telomeres produced by leading- versus lagging-strand synthesis, and replication timing of mammalian telomeres.
Characterization of all human male synaptonemal complexes by subtelomere multiplex-FISH
Authors: Codina-Pascual M. , Kraus J. , Speicher M.R. , Oliver-Bonet M. , Murcia V. , Sarquella J. , Egozcue J. , Navarro J. , Benet J.
Published: August 2004

During meiotic prophase I, homologous chromosomes synapse and recombine. Both events are of vital importance for the success of meiosis. When homologous chromosomes synapse, a proteinaceous structure called synaptonemal complex (SC) appears along the pairing axis and meiotic recombination takes place. The existence of immunolabeling techniques for SC proteins (SCP1, SCP2 and SCP3) and for DNA mismatch repair proteins present in late recombination nodules (MLH1) allow analyses of both synapsis and meiotic recombination in the gametocyte I. In situ hybridization methods can be applied afterwards because chromatin is preserved during cell fixation for immunoanalysis. The combination of both methodologies allows the analysis of synapsis and the creation of recombination maps for each bivalent. In this work we apply the seven-fluorochrome subtelomere-specific multiplex FISH assay (stM-FISH) to human male meiotic cells previously labeled by immunofluorescence (SCP1, SCP3, MLH1, CENP) to assess its utility for human SC karyotyping. This FISH method consists of microdissected subtelomeric probes labeled combinatorially with seven different fluorochromes. Results prove its usefulness for the identification of all human SCs. Furthermore, by labeling subtelomeric regions this one-single-step method enables the characterization of interstitial and terminal SC fragments and SC delineation even if superposition is present in pachytene spreads.
Alteration of the metaphase checkpoint by B chromosomes
Authors: Herron W.B. , Lluesma S.M. , Arana P. , Wise D.
Published: August 2004

The B chromosome polymorphism in Spanish populations of the grasshopper, Eyprepocnemis plorans (Charpentier) is ancient and widespread. Meiocytes containing B chromosomes were analyzed in our laboratory using the 3F3/2 monoclonal antibody, which binds to a kinetochore phosphoepitope whose degree of phosphorylation is sensitive to tension applied to the kinetochore. Further, the tension created by the spindle at metaphase controls a checkpoint (the metaphase checkpoint) that allows the cell to begin anaphase when all chromosomes are aligned at the metaphase plate. Fluorescence patterns of the 3F3/2 phosphoepitope in cells containing B chromosomes were determined using confocal laser scanning microscopy. The phosphorylation pattern of kinetochores in these cells was shown to be different from that of cells without Bs. This suggests that the metaphase checkpoint has been modified in some way. We propose that B chromosomes in these grasshopper populations may have survived during evolution due to an alteration of the metaphase checkpoint, making it more permissive to the presence of misaligned chromosomes.
Imaging of human metaphase chromosomes by atomic force microscopy in liquid
Authors: Hoshi O. , Owen R. , Miles M. , Ushiki T.
Published: August 2004

Human metaphase chromosomes were observed using an intermittent contact mode of atomic force microscopy (AFM) in a phosphate-buffered saline solution to clarify their conformation close to that in the physiological state. In the AFM images in liquid, symmetric alternating ridges and grooves were evident on their surface of the paired sister chromatids. The number of the ridges and grooves were rather specific to the type of the chromosome. The structural changes of chromosomes caused by trypsin treatment were also directly observable using AFM in liquid. These results suggest that the intermittent contact mode AFM is useful not only for analyzing the structure of chromosomes in a liquid condition but also for studying the effect of chemical treatments on chromosomes in relation to their structural changes.
LNA-modified oligonucleotides are highly efficient as FISH probes
Authors: Silahtaroglu A. , Pfundheller H. , Koshkin A. , Tommerup N. , Kauppinen S.
Published: August 2004

Fluorescence in situ hybridization (FISH) is a highly useful technique with a wide range of applications including the delineation of complex karyotypes, prenatal diagnosis of aneuploidies, screening for diagnostic or prognostic markers in cancer cells, gene mapping and gene expression studies. However, it is still a fairly time-consuming method with limitations in both sensitivity and resolution. Locked Nucleic Acids (LNAs) constitute a novel class of RNA analogs that have an exceptionally high affinity towards complementary DNA and RNA. Substitution of DNA oligonucleotide probes with LNA has shown to significantly increase their thermal duplex stability as well as to improve the discrimination between perfectly matched and mismatched target nucleic acids. To exploit the improved hybridization properties of LNA oligonucleotides in FISH, we have designed several LNA substituted oligonucleotide probes specific to different human-specific repetitive elements, such as the classical satellite-2, telomere and alpha-satellite repeats. In the present study we show that LNA modified oligonucleotides are excellent probes in FISH, combining high binding affinity with short hybridization time.
Genome architecture studied by nanoscale imaging: analyses among bacterial phyla and their implication to eukaryotic genome folding
Authors: Takeyasu K. , Kim J. , Ohniwa R.L. , Kobori T. , Inose Y. , Morikawa K. , Ohta T. , Ishihama A. , Yoshimura S.H.
Published: August 2004

The proper function of the genome largely depends on the higher order architecture of the chromosome. Our previous application of nanotechnology to the questions regarding the structural basis for such macromolecular dynamics has shown that the higher order architecture of the Escherichia coli genome (nucleoid) is achieved via several steps of DNA folding (Kim et al., 2004). In this study, the hierarchy of genome organization was compared among E. coli, Staphylococcus aureus and Clostridium perfringens. A one-molecule-imaging technique, atomic force microscopy (AFM), was applied to the E. coli cells on a cover glass that were successively treated with a detergent, and demonstrated that the nucleoids consist of a fundamental fibrous structure with a diameter of 80 nm that was further dissected into a 40-nm fiber. An application of this on-substrate procedure to the S. aureus and the C. perfringens nucleoids revealed that they also possessed the 40- and 80-nm fibers that were sustainable in the mild detergent solution. The E. coli nucleoid dynamically changed its structure during cell growth; the 80-nm fibers releasable from the cell could be transformed into a tightly packed state depending upon the expression of Dps. However, the S. aureus and the C. perfringens nucleoids never underwent such tight compaction when they reached stationary phase. Bioinformatic analysis suggested that this was possibly due to the lack of a nucleoid protein, Dps, in both species. AFM analysis revealed that both the mitotic chromosome and the interphase chromatin of human cells were also composed of 80-nm fibers. Taking all together, we propose a structural model of the bacterial nucleoid in which a fundamental mechanism of chromosome packing is common in both prokaryotes and eukaryotes.
Protein composition of human metaphase chromosomes analyzed by two-dimensional electrophoreses
Authors: Uchiyama S. , Kobayashi S. , Takata H. , Ishihara T. , Sone T. , Matsunaga S. , Fukui K.
Published: August 2004

A large amount of metaphase chromosomes were isolated from synchronized human cell lines by a polyamine procedure. All the chromosomal proteins extracted by an acetic acid extraction method were fully dissolved into the sample solutions for isoelectric focusing (IEF) or radical free and highly reduced (RFHR) two-dimensional electrophoreses (2-DEs). As a result, well-separated and highly reproducible 2-DE patterns were obtained. This could not be attained by an ordinary acetone precipitation method. The 2-DE patterns visualized using Coomassie Brilliant Blue (CBB) staining indicated that more than one hundred proteins were involved in the isolated metaphase chromosomes, although the most abundant proteins, histones, occupied a greater part of the chromosomal proteins. It was also shown that colcemid treatment for cell cycle synchronization had little effect on the 2-DE pattern compared to that obtained without the treatment. Furthermore, no significant differences were observed in the 2-DE patterns among the chromosomal proteins prepared from two different human cell lines, BALL-1 and K562. However, 2-DE analysis of isolated metaphase chromosomes from HeLa cells apparently showed a smaller number of proteins than the BALL-1 and K562 cell lines at a neutral pI range. The present study paves the way for elucidating protein composition of human metaphase chromosomes.
Small supernumerary marker chromosomes (sSMC) in humans
Authors: Liehr T. , Claussen U. , Starke H.
Published: August 2004

Small supernumerary marker chromosomes (sSMC), defined as additional centric chromosome fragments too small to be identified or characterized unambiguously by banding cytogenetics alone, are present in 0.043% of newborn children. Several attempts have been made to correlate certain sSMC with a specific clinical picture, resulting in the description of several syndromes such as the i(18p)-, der(22)-, i(12p)- (Pallister Killian syndrome) and inv dup(22)- (cat-eye) syndromes. However, most of the remaining sSMC including minute-, ring-, inverted-duplication- as well as complex-rearranged chromosomes, have not yet been correlated with clinical syndromes, mostly due to problems in their comprehensive characterization. Here we present an overview of sSMC, including the first attempt to address problems of nomenclature and their modes of formation, problems connected with mosaicism plus familial occurrence. The review also discusses the frequency of sSMC in prenatal, postnatal, and clinical cases, their chromosomal origin and their association with uniparental disomy. A short review of the up-to-date approaches available for sSMC characterization is included. Clinically relevant correlations concerning the presence of a specific sSMC and its phenotypic consequences should become available soon.
Cloning of the breakpoints of a de novo inversion of chromosome 8, inv (8)(p11.2q23.1) in a patient with Ambras syndrome
Authors: Tadin-Strapps M. , Warburton D. , Baumeister F.A.M. , Fischer S.G. , Yonan J. , Gilliam T.C. , Christiano A.M.
Published: August 2004

Ambras syndrome (AMS) is a unique form of universal congenital hypertrichosis. In patients with this syndrome, the whole body is covered with fine long hair, except for areas where normally no hair grows. There is accompanying facial dysmorphism and teeth abnormalities, including retarded first and second dentition and absence of teeth. In 1993, Baumeister et al. reported an isolated case of Ambras syndrome in association with a pericentric inversion of chromosome 8. Subsequently, another patient with congenital hypertrichosis and rearrangement of chromosome 8 was reported by Balducci et al. (1998). Both of these patients have a breakpoint in 8q22 in common suggesting that this region of chromosome 8 contains a gene involved in regulation of hair growth. In order to precisely determine the nature of the rearrangement in the case of Ambras syndrome, we have used fluorescent in situ hybridization (FISH) analysis. We have cloned the inversion breakpoints in this patient and generated a detailed physical map of the inversion breakpoint interval. Analysis of the transcripts that map in the vicinity of the breakpoints revealed that the inversion does not disrupt a gene, and suggests that the phenotype is caused by a position effect.
High-resolution cDNA microarray CGH mapping of genomic imbalances in osteosarcoma using formalin-fixed paraffin-embedded tissue
Authors: Zielenska M. , Marrano P. , Thorner P. , Pei J. , Beheshti B. , Ho M. , Bayani J. , Liu Y. , Sun B.C. , Squire J.A. , Hao X.-S.
Published: August 2004

Formalin-fixed paraffin embedded (FFPE) tumor tissue provides an opportunity to perform retrospective genomic studies of tumors in which chromosomal imbalances are strongly associated with oncogenesis. The application of comparative genomic hybridization (CGH) has led to the rapid accumulation of cytogenetic information on osteosarcoma (OS); however, the limited resolving power of metaphase CGH does not permit precise mapping of imbalances. Array CGH allows quantitative detection and more precise delineation of copy number aberrations in tumors. Unfortunately the high cost and lower density of BACs on available commercial arrays has limited the ability to comprehensively profile copy number changes in tumors such as OS that are recurrently subject to genomic imbalance. In this study a cDNA/EST microarray including 18,980 human cDNAs (which represent all 22 pairs of autosomal chromosomes and chromosome X) was used for CGH analysis of eight OS FFPE. Chromosomes 1, 12, 17, and X harbored the most imbalances. Gain/amplification of X was observed in 4/8 OS, and in keeping with other recent genomic analyses of OS, gain/amplification of 17p11.2 was often accompanied by a distal deletion in the region of the p53 gene. Gain/amplification of the X chromosome was verified using interphase FISH carried out on a subset of OS FFPE sections and OS tissue arrays.
The relationship between male infertility and increased levels of sperm disomy
Authors: Tempest H.G. , Griffin D.K.
Published: August 2004

Sperm chromosome abnormalities cut across a number of areas relevant to ICC XV. The association between increased levels of sperm aneuploidy (usually disomy) and male infertility has implications for the sessions on reproduction, sex chromosomes, aneuploidy and meiosis and was, to the best of our knowledge, first reported in 1995. Since then most studies have reported similar increases of varying degrees but, despite this, a small number of laboratories have presented results that demonstrate no significant association. The purpose of this article is to review the state of the art in this area and to speculate as to reasons for the differences in reports from different laboratories. The findings are broken down by chromosome with studies of the sex chromosomes being broken down further to indicate meiotic stages of origin. We conclude that comparisons are difficult to make since many studies do not clearly define patient and control groups. Nevertheless, despite these and other differences (such as scoring criteria, technical differences, demographics, etc.), the consensus in the literature is that a strong correlation exists between sperm aneuploidy and male infertility. The nature of that relationship will be further defined when andrological criteria are more closely taken into account and protocols for preparation and scoring are standardised.
Low level chromosome instability in embryonic cells of primary aneuploid mice
Authors: Lightfoot D.A. , Höög C.
Published: August 2004

Karyotypic analyses of Down syndrome patients have identified a low level of chromosome mosaicism, suggesting that the primary aneuploid status of the cells promotes further chromosomal segregation errors. Sycp3-null female mice produce aneuploid oocytes, which after fusion with normal haploid sperm, result in offspring with systemic whole chromosome, aneuploid embryo cells. Using the Sycp3-null female as a model, we observe an increase in the number of embryonic cells at E7.0 that exhibit abnormal chromosomal bridges at the anaphas estage of mitosis. This result suggests that global changes in gene expression patterns resulting from primary aneuploidy can affect mitotic chromosome segregation, resulting in a low level of chromosomal instability. The increased level of chromosomal instability could in the absence of mitotic checkpoints, lead to chromosomal mosaicism within the adult organism, as seen in Down syndrome patients.
Chromosomal localization of telomeric sequences in three species of Akodon (Rodentia, Sigmodontinae)
Authors: Viera A. , Ortiz M.I. , Pinna-Senn E. , Dalmasso G. , Bella J.L. , Lisanti J.A.
Published: August 2004

The distribution of the vertebrate telomeric sequence T2AG3 in three species of the rodent genus Akodon was examined by FISH with a peptide nucleic acid probe. In addition to the expected telomeric hybridization, non-telomeric signals were observed in the three species. In A. dolores, centromeric signals were visible in two of the four biarmed autosome pairs featuring Robertsonian polymorphism, indicating the retention of at least part of the telomeric sequences during the fusion process, and an interstitial signal of lower intensity was observed in the short arm of another. In A. boliviensis, a strong signal was observed near the centromeric end of the first chromosome pair. The first pair of A. azarae (homologous to the first pair of A. boliviensis) showed a similar but markedly amplified signal, and a subcentromeric signal in the X chromosome corresponding to a heterochromatic region; additionally, interstitial signals of lower intensity were present in one to four chromosomes in the majority of cells examined.
Molecular characterization of the porcine TYK2 gene on SSC 2q1.3→q2.1
Authors: Leeb T. , Martins-Wess F. , Kuiper H. , Lassnig C. , Distl O. , Müller M.
Published: August 2004

TYK2 is a member of the janus protein kinase family and plays an important role in the signal transduction of various cytokines including interferon α/β. Cloning and characterization of the porcine TYK2 gene revealed a conserved organization with respect to other mammalian TYK2 orthologs. The porcine gene consists of 25 exons spanning approximately 26 kb and encoding a 5.3-kb mRNA. It is located in a GC-rich and gene-rich chromosome region and contains several CpG islands. The predicted 132-kDa TYK2 protein consists of 1,184 amino acids and shows 85% identity to the human TYK2 protein. The porcine TYK2 gene was localized by FISH and RH-mapping on SSC 2q1.3→q2.1, which is in good agreement with established human-mouse-pig comparative maps.
A reassessment of imprinting regions and phenotypes on mouse chromosome 6: Nap1l5 locates within the currently defined sub-proximal imprinting region
Authors: Beechey C.V.
Published: August 2004

Previous studies (Beechey, 2000) have shown that mouse proximal chromosome (Chr) 6 has two imprinting regions. An early embryonic lethality is associated with two maternal copies of the more proximal imprinting region, while mice with two maternal copies of the sub-proximal imprinting region are growth retarded at birth, the weight reduction remaining similar to adulthood. No detectable postnatal imprinting phenotype was seen in these earlier studies with two paternal copies of either region. The sub-proximal imprinting region locates distal to the T77H reciprocal translocation breakpoint in G-band 6A3.2 and results reported here show that it does not extend beyond the breakpoint of the more distal T6Ad translocation in 6C2. It has been confirmed that the postnatal growth retardation observed with two maternal copies of the sub-proximal region is established in utero, although placental size was normal. A new finding is that 16.5–18.5-dpc embryos, with two paternal copies of the sub-proximal imprinting region, were larger than their normal sibs, although placental size was normal. As no postnatal growth differences have been observed in these mice, the fetal overgrowth must normalize by birth. The imprinted genes Peg1/Mest, Copg2, Copg2as and Mit1/Lb9 map to the sub-proximal imprinting region and are thus candidates for the observed imprinting phenotypes. Another candidate is the recently reported imprinted gene Nap1l5. Expression studies of Nap1l5 in mice with two maternal or two paternal copies of different regions of Chr 6 have demonstrated that the gene locates within the sub-proximal imprinting region. FISH has mapped Nap1l5 to G-band 6C1, within the sub-proximal imprinting region but several G-bands distal to the Peg1/Mest cluster. This location, and the 30-Mb separation of these loci on the sequence map, makes it probable that Nap1l5 defines a new imprinting domain within the currently defined sub-proximal imprinting region.