bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF SPACEFLIGHT CONDITIONS ON FERTILIZATION AND EMBRYOGENESIS IN THE SEA URCHIN LYTECHINUS PICTUS
Authors: Schatten Heide , Chakrabarti Amitabha , Taylor Meghan , Sommer Laurel , Levine Howard , Anderson Ken , Runco Mario , Kemp Raelynn
Published: October 2002

Calcium loss and muscle atrophy are two of the main metabolic changes experienced by astronauts and crew members during exposure to microgravity in space. Calcium and cytoskeletal events were investigated within sea urchin embryos which were cultured in space under both microgravity and 1g conditions. Embryos were fixed at time‐points ranging from 3h to 8 days after fertilization. Investigative emphasis was placed upon: (1) sperm‐induced calcium‐dependent exocytosis and cortical granule secretion, (2) membrane fusion of cortical granule and plasma membranes; (3) microfilament polymerization and microvilli elongation; and (5) embryonic development into morula, blastula, gastrula, and pluteus stages. For embryos cultured under microgravity conditions, the processes of cortical granule discharge, fusion of cortical granule membranes with the plasma membrane, elongation of microvilli and elevation of the fertilization coat were reduced in comparison with embryos cultured at 1g in space and under normal conditions on Earth. Also, 4% of all cells undergoing division in microgravity showed abnormalities in the centrosome‐centriole complex. These abnormalities were not observed within the 1g flight and ground control specimens, indicating that significant alterations in sea urchin development processes occur under microgravity conditions.
MICROTUBULE FORMATION AND KINESIN‐DRIVEN MICROTUBULE GLIDING IN VITRO IN THE PRESENCE OF LIPOPOLYSACCHARIDE
Authors: Böhm Konrad J. , Russwurm Stefan , Ghaleb Nagib , Reinhart Konrad , Unger Eberhard
Published: October 2002

Lipopolysaccharide (LPS) is a main trigger substance for the development of septic shock and multiple organ failure. We showed by turbidity measurements that LPS inhibits microtubule formation in a pH‐dependent manner. Inhibition was found to be not only due to sequestration of MAP2 by LPS, but also of MAP1 and tau MAPs, indicating that LPS is able to react with a broad variety of MAPs. LPS‐induced inhibition of microtubule formation could be compensated by additional tau or by addition of taxol. Dot blots revealed that LPS binds directly to tau, but seems not to bind to tubulin. As tau is expressed in various tissue types involved in multiorgan failure, it might be regarded as a further target for LPS action. In contrast, kinesin‐dependent microtubule gliding was not affected by LPS. The toxin neither blocked the cargo (vesicle) nor the microtubule binding site of kinesin, suggesting a certain specificity of LPS‐MAP interaction.
ANDROGEN DEPENDENT EXPRESSION OF AT1 RECEPTOR AND ITS REGULATION OF ANION SECRETION IN RAT EPIDIDYMIS
Authors: Leung P. S. , Wong T. P. , Chung Y. W. , Chan H. C.
Published: October 2002

Our previous studies have provided solid evidence for the presence of an intrinsic angiotensin‐generating system in the rat epididymis, which plays an important role in the regulation of the anion and thus fluid secretion by the epididymal epithelium. In the present study, the effect of androgen on the expression of AT1receptor and its subsequent regulation of anion secretion by the epididymis were investigated using Western blotting, semi‐quantitative reverse transcription‐polymerase chain reaction (RT‐PCR) and in vitro electrophysiological approaches. Results from Western blotting analysis showed that the expression of AT1receptor protein was almost abolished by castration whereas its expression was completely restored to the control level when the castrated rats were hormonally replaced with testosterone. Efferent duct ligation, however, appeared not to affect the expression of AT1receptor protein by the epididymis. Results from RT‐PCR showed that mRNA expression of AT1receptor was consistent with that observed in protein expression. Results from short‐circuit current (ISC) showed that castration almost abolished the angiotensin II‐induced ISC. However, efferent duct ligation did not affect the angiotensin II‐induced ISC, which was completely blocked in the presence of losartan, a specific antagonist of the AT1receptor. These data indicate that the expression of epididymal AT1receptor is predominantly influenced by testicular androgens but not by testicular factors. This androgen‐dependent expression of AT1receptor could have a role in the control of AT1receptor‐mediated anion secretion and thus fluid secretion by the rat epididymis.
PRODUCTION AND CHARACTERIZATION OF ESCHERICHIA COLI ENTEROHEMOLYSIN AND ITS EFFECTS ON THE STRUCTURE OF ERYTHROCYTE MEMBRANES
Authors: Jürgens Dagmar , Özel Muhsin , Takaisi‐Kikuni Ntondo B.
Published: October 2002

Hemolysins are cell‐damaging protein toxins produced by pathogenic bacteria, which are usually released into the extracellular medium. Escherichia coli enterohemolysin is an intracellular toxin produced during the log phase of growth, with a maximal intracellular accumulation in the late log phase. In the present study, we have employed electron microscopy and SDS‐PAGE to assess the effects of enterohemolysin on erythocyte membranes from different species. The erythrocyte cell damage began immediately after exposure to enterohemolysin with chemically detectable changes in cell membrane permeability, and the formation of surface lesions which increased rapidly in size. This process resulted in complete cell destruction. Ring‐shaped structures with a diameter of 10nm were observed by electron microscopy after treatment of horse erythrocyte membranes with enterohemolysin. The ring structures were found clustered and irregularly distributed on the surface of the membranes. Following incubation of the toxin with horse erythrocyte ghosts and detergent‐solubilization, the enterohemolysin was isolated from the cytoplasm in its membrane‐bound form by sucrose density gradient. SDS‐PAGE and silver staining of deoxycholate‐solubilized target membranes revealed heterogeneous forms of the toxin. By using SDS‐PAGE and gel filtration, the molecular weight of the toxin was estimated to be 35kDa. With respect to species specificity, horse erythrocytes showed the highest sensitivity to the enterohemolysin, followed by human and guinea pig erythrocytes. The hemolytic sensitivity correlated with the toxin binding capacity of erythrocyte membranes of different animal species. The degree of hemolysis was unaffected by temperature in the range of 4°C–37°C and was optimal at pH 9.0. In contrast to pore‐forming cytolysins, the hemolytic activity of enterohemolysin was enhanced continuously in the presence of increasing concentrations of dextran 4 and dextran 8 within the range of 5 to 30mM. Trypsin sensitivity of membrane‐bound enterohemolysin indicates that the cell surface is the most likely target site for this toxin. Additionally, the fact that proteinase and phosphatase inhibitors failed to inhibit lysis suggests that enterohemolysin alters and disrupts cell membranes by a detergent‐like mechanism.
EFFECT OF ANTISENSE hTERT mRNA OLIGODEOXYNUCLEOTIDE ON TELOMERASE ACTIVITY OF LEUKEMIC CELLS
Authors: Zhang Y. , He D. M.
Published: October 2002

The effect of antisense hTERT mRNA oligodeoxynucleotide on telomerase activity of leukemia cells was explored and investigated in the present study. Telomerase activity was measured by the telomerase PCR ELISA assay kit (TRAP); hTERT mRNA expression by reverse transcription polymerase chain reaction (RT‐PCR) assay and gel‐image system, hTERT protein by immunochemistry and flowcytometry. Results showed Incubation of leukemic cells (HL‐60 and K562 cell lines) with 10μmol/l AS PS‐ODN would significantly reduce the their mRNA levels and in vitro expression of hTERT protein 24h later, so that the telomerase activity would be significantly down‐regulated or inhibited. In conlusion, the hTERT AS PS‐ODN is an excellent inhibitor for telomerase activity.
ORGANIZATION OF HIGHER‐LEVEL CHROMATIN STRUCTURES (CHROMOMERE, CHROMONEMA AND CHROMATIN BLOCK) EXAMINED USING VISIBLE LIGHT‐INDUCED CHROMATIN PHOTO‐STABILIZATION
Authors: Sheval E. V. , Prusov A. N. , Kireev I. I. , Fais D. , Polyakov V. Yu.
Published: October 2002

The method of chromatin photo‐stabilization by the action of visible light in the presence of ethidium bromide was used for investigation of higher‐level chromatin structures in isolated nuclei. As a model we used rat hepatocyte nuclei isolated in buffers which stabilized or destabilized nuclear matrix. Several higher‐level chromatin structures were visualized: 100nm globules—chromomeres, chains of chromomeres—chromonemata, aggregates of chromomeres—blocks of condensed chromatin. All these structures were completely destroyed by 2M NaCl extraction independent of the matrix state, and DNA was extruded from the residual nuclei (nuclear matrices) into a halo. These results show that nuclear matrix proteins do not play the main role in the maintenance of higher‐level chromatin structures. Preliminary irradiation led to the reduction of the halo width in the dose‐dependent manner. In regions of condensed chromatin of irradiated nucleoids there were discrete complexes consisting of DNA fibers radiating from an electron‐dense core and resembling the decondensed chromomeres or the rosette‐like structures. As shown by the analysis of proteins bound to irradiated nuclei upon high‐salt extraction, irradiation presumably stabilized the non‐histone proteins. These results suggest that in interphase nuclei loop domains are folded into discrete higher‐level chromatin complexes (chromomeres). These complexes are possibly maintained by putative non‐histone proteins, which are extracted with high‐salt buffers from non‐irradiated nuclei.
SIMPLE SEPARATION OF CHICKEN GONADAL PRIMORDIAL GERM CELLS WITH AND WITHOUT FOREIGN GENES
Authors: Jeong Dong Kee , Hong Yeong Ho , Han Jae Yong
Published: October 2002

Simplicity is the key element of an inexpensive technique described that is superior in performance to previous methods. It can make it the rapid method of choice to obtain reasonable yields of purified primordial germ cells (PGCs) for immediate production of germline chimeric chickens with integrated foreign genes. After Ficoll centrifugation, the purity of PGCs from gonads was 80.9±0.08% (mechanical) compared with 86.1±0.19% (enzymatic). GFP gene and lacZ‐transduced chicken gonadal primordial germ cells (gPGCs) examined 72h after transduction had a transfection efficiency of ∼61% and ∼64%, respectively. After 10 days of G418 selection, approximately 90 and 92% of pure gPGCs did not contain other cells following this Ficoll gradient centrifugation method of preparation.
Cetradonia, a New Genus in the New Family Cetradoniaceae (Lecanorales, Ascomycota)
Authors: Wei Jiang-chun , Ahti Teuvo
Published: October 2002

A taxonomic revision of the lichen genus Gymnoderma Nyl. sensu Yoshimura & Sharp (Cladoniaceae) based on an integrative analysis of polyphasic characters supports the segregation of a new genus Cetradonia J.-C.Wei & Ahti in a new family Cetradoniaceae J.-C.Wei & Ahti. The monotypic genus and family are based on Cladonia linearis Evans. In addition, two species are recognized in genus Neophyllis F. Wilson and two species are retained in the genus Gymnoderma Nyl. of the Cladoniaceae.
Stereocaulon Cumulatum Comb, nov., Another Crustose Species in the Genus
Authors: Timdal E.
Published: October 2002

The new combination Stereocaulon cumulatum (Sommerf.) Timdal is made for the northern Eurasian and Greenlandic, arctic-alpine, terricolous lichen presently known as Toninia cumulate (Sommerf.) Th. Fr.
Late Pleistocene and Holocene Paleoenvironments of Chalco Lake, Central Mexico
Authors: Lozano-Garcı́a Maria Socorro , Ortega-Guerrero Beatriz , Caballero-Miranda Margarita , Urrutia-Fucugauchi Jaime
Published: October 2002

In order to establish paleoenvironmental conditions during the late Quaternary, four cores from the Basin of Mexico (central Mexico) were drilled in Chalco Lake, located in the southeastern part of the basin. The upper 8 m of two parallel cores were studied, using paleomagnetic, loss-on-ignition, pollen, and diatom analyses. Based on 11 14C ages, the analyzed record spans the last 19,000 14C yr B.P. Volcanic activity has affected microfossil abundances, both directly and indirectly, resulting in absence or reduction of pollen and diatom assemblages. Important volcanic activity took place between 19,000 and 15,000 yr B.P. when the lake was a shallow alkaline marsh and an increase of grassland pollen suggests a dry, cold climate. During this interval, abrupt environmental changes with increasing moisture occurred. From 15,000 until 12,500 yr B.P. the lake level increased and the pollen indicates wetter conditions. The highest lake level is registered from 12,500 to ca. 9000 yr B.P. The end of the Pleistocene is characterized by an increase in humidity. From 9000 until ca. 3000 yr B.P. Chalco Lake was a saline marsh and the pollen record indicates warmer conditions. After 3000 yr B.P. the lake level increased and human disturbance dominates the lacustrine record.
Relative Dating of Terraces of the Owens River, Northern Owens Valley, California, and Correlation with Moraines of the Sierra Nevada
Authors: Pinter Nicholas , Keller Edward A. , West Robert B.
Published: October 2002

In the northern Owens Valley, the Owens River has cut and preserved three terraces uplifted above its modern floodplain. We have analyzed soils and used other relative-dating techniques in order to differentiate the terrace surfaces, to correlate from the terraces to moraines of the eastern Sierra Nevada, and to test the effects of relief and climatic differences on relative-dating results. Most of the relative-dating techniques attempted were successful in differentiating the terraces of the Owens River sequence. In addition, weathering rinds, soil descriptions, and an early Holocene14C date for the youngest terrace support correlation of the three terrace levels with the three post-Sherwin-age glacial stages (Tioga, Tahoe, and pre-Tahoe) found in nearby canyons of the Sierra Nevada. Other relative-dating techniques that are commonly employed, however, suggest distinct differences between the terrace and moraine sequences. These differences probably reflect the difference in relief, such that slow erosion of the moraine crests may have retarded soil development relative to the flat terrace surfaces and altered surface-weathering processes. Use of relative-dating analyses to correlate between dissimilar geomorphic systems requires caution but use of a broad range of techniques and absolute-age calibration may make correlation possible.
High-Resolution Paleotemperature Proxy Record for the Last Interglaciation Based on Norwegian Speleothems
Authors: Lauritzen Stein-Erik
Published: October 2002

Two speleothems from a coastal lowland and an alpine cave site in northern Norway grew in isotopic equilibrium during Termination II and marine isotope stage 5 (150,000-80,000 yr B.P.), as dated by the U-series technique. The stable isotope record (δ18O, δ13C) displays a time resolution down to ∼20 yr. The δ18Oc signal in the two speleothems appears to be mainly dominated by the meteoric signal; i.e., there is a positive relationship between δ18Oc and temperature [∂(δ18Oc/∂T > 0]. The FM-2 couplet, a Younger Dryas type two-step structure in Termination II at 132,000 ± 5000 and 129,000 ± 5000 yr is prominent in the speleothem record. The record correlates well with details and gross features of the GRIP ice core and confirms the time scale and the unstable climate proposed for substage 5e. The isotopic response in Termination II is delayed relative to the Devil's Hole record and is in accord with the SPECMAP chronology, but cooling at the end of substage 5e seems to be synchronous between Devil's Hole and the Norwegian flowstones.
Was There a Pliocene-Pleistocene Fluvial-Lacustrine Connection between Death Valley and the Colorado River?
Authors: Brown William J. , Rosen Michael R.
Published: October 2002

Since the turn of the century, a Pliocene-Pleistocene connection between the Death Valley-Owens River pluvial system and the Colorado River drainage basin has been frequently postulated. The two most commonly proposed routes involve (1) a southward overflow from the Death Valley Lake system or (2) southward migration of the Mojave River between its present course and a more southerly route. Under the present topographic regime, a Death Valley Lake capable of overflowing the bedrock saddle at Ludlow, California and discharging southward into the Bristol, Cadiz, and Danby Lake basins (and eventually the Colorado River) would be over 12,000 km2 in size. Few surface and subsurface indicators exist to support either a fluvial or lacustrine connection. Evidence from deep cores and boreholes drilled in Soda, Bristol, Cadiz, and Danby dry lake basins indicate that a hydrologic connection has not occurred during the past 4 myr. No well-documented paleoshoreline features have been located at elevations corresponding to the above hydrologic systems in Death Valley, Silver-Soda, Bristol, or Danby Lake basins. In the Cadiz, Silurian, and Broadwell basins these features have not been found at all. Therefore, we conclude that a hydrologic connection between the Death Valley-Owens River system and the Colorado River has not occurred along either of these routes since the middle Pliocene.
Stability of Wood Anatomy of Living and Holocene Thuja occidentalis L. Derived from Exposed and Submerged Portions of the Niagara Escarpment
Authors: Larson Douglas W. , Melville Lewis
Published: October 2002

Millennium-long tree-ring chronologies have recently been derived fromThuja occidentalis L. growing on the exposed cliffs of the Niagara Escarpment, Canada. Lengthening of these chronologies may be possible by incorporating tree-ring series from subaerially exposed and submerged subfossil wood, provided that its anatomy is not significantly influenced by time or treatment. In order to determine if Holocene-age samples would be suitable for incorporation into very long tree-ring chronologies, a study was undertaken comparing wood structure of living trees, dead trees exposed to the air during the late Holocene, and dead trees submerged since the early Holocene. The results show that the impact of time and environment on wood anatomy is considerably less than expected. The anatomy of annual rings in Holocene trees is similar to that found in modern specimens. High magnification scanning electron micrographs show that tracheid walls lose their rectangular appearance after 8000 yr, but few other signs of deterioration are present. The results mean that Holocene wood can be used to add to the long dendrochronological record that has already been produced from the Niagara Escarpment.
Isotopic Fingerprints of Paleoclimates during the Last 30,000 Years in Deep Confined Groundwaters of Southern India
Authors: Sukhija Balbir Singh , Reddy Dontireddy Venkat , Nagabhushanam Pasupuleti
Published: October 2002

Isotopic and geochemical evidence of paleoclimates, especially for the last glaciation, has been obtained from deep confined groundwaters of southern India. The δ13C, δ18O, chloride, and deuterium analyses of groundwaters show distinct excursions inferred to be related to climatic variations. The arid climatic episode associated with the last glaciation (18,000 ± 2000 yr B.P.) is conspicuously identified by signatures of relatively enriched δ13C (−10 to −12‰ PDB) and δ18O (−5.3 to −4.8‰ SMOW) values, and high chloride concentration (80 to 160 mg/l). The transition from an arid to humid period ca. 12,000–8000 yr B.P. is shown by a decreasing trend in the δ13C (−9.5 to −17‰) and δ18O (−4.5 to −6.3‰) contents of groundwaters. The late Holocene (since 4000 yr B.P.), marked by a more humid but unstable climate, is identified by further depletion of δ13C (−13 to −20‰) and δ18O (−5.2 to −6.3‰). Similar variation between δ18O and chloride values in confined groundwaters further demonstrates two distinct climatic excursions (arid and humid) governed by the “amount effect.” This is the first time that isotopic and geochemical signatures related to changing paleoclimates have been identified in the confined groundwaters of the southern Indian landmass.
What are X-Machines?
Authors: Holcombe Mike
Published: October 2002

X-machines were introduced by S. Eilenberg in 1974 ([Eil74]) as a mathematical framework for examining the relationships between languages and automata. The X-machine definition provided a very general concept that captured in a simple and elegant way a wide variety of existing models and their computational behaviour. Thus finite state machines, pushdown automata and Turing machines all provided different examples of X-machines obtained by varying some of the components of the X-machine's definition.
Demonstrating the Cognitive Plausibility of Interactive System Specifications
Authors: Butterworth Richard , Blandford Ann , Duke David
Published: October 2002

Much of the behaviour of an interactive system is determined by its user population. This paper describes how assumptions about the user can be brought into system models in order to reason about their behaviour. We describe a system model containing reasonable assumptions about the user as being ‘cognitively plausible’. Before asserting the plausibility of a model however we must first be able to make the assumptions made in that model inspectable.

There is a tension between the inspectability of user assumptions and the tractability of models; inspectable models tend to not be very tractable and
vice versa
. We describe how we can get round this tension, by deriving tractable models from explicit user assumptions. The resulting models may not of themselves be very inspectable to human-factors workers, but the process by which they are derived is inspectable. Hence we claim that we can have both tractability and inspectability. We exemplify our claims using a simple cognitive model and ‘Meeting Maker’, an interactive electronic diary system.
A Nitpick Analysis of Mobile IPv6
Authors: Jackson Daniel , Ng Yu-Chung , Wing Jeannette
Published: October 2002

A lightweight formal method enables partial specification and automatic analysis by sacrificing breadth of coverage and expressive power. NP is a specification language that is a subset of Z, and Nitpick is a tool that quickly and automatically checks properties of finite models of systems specified in NP. We used NP to state two critical acyclicity properties of Mobile IPv6, a new internetworking protocol that allows mobile hosts to communicate with each other. In our Nitpick analysis of Mobile IPv6 we discovered a design flaw: one of the acyclicity properties does not hold. It takes only two hosts to exhibit this flaw. This paper gives self-contained overviews of Mobile IPv6 and of NP and Nitpick sufficient to understand the details of our specification and analysis.
Lymph node staging of esophageal squamous cell carcinoma in patients with and without neoadjuvant radiochemotherapy: Histomorphologic analysis
Authors: Schröder Wolfgang , Baldus Stephan E. , Mönig Stefan P. , Beckurts Tobias K. E. , Dienes Hans P. , Hölscher Arnulf H.
Published: October 2002

In patients with squamous cell carcinoma of the esophagus, the preoperative clinical staging of the N category is primarily based on the lymph node size. Lymph nodes >10 mm are considered to be tumor‐infiltrated. This histopathologic study investigated the correlation of lymph node size and metastatic infiltration in esophageal carcinoma of patients with and without neoadjuvant radiochemotherapy. The specimens of 40 patients with squamous cell carcinoma of the esophagus were included in a prospective morphometric study. Half of these patients (n=20) received preoperative radiochemotherapy. The number of resected lymph nodes were counted, and the largest diameter of each node was measured. Metastatic involvement of each node was analyzed by histologic examination. The frequency of lymph node metastases was calculated and correlated to the lymph node size. A total of 1196 lymph nodes with an average of 29.9 nodes per patient were resected and analyzed; 129 lymph nodes (10.8%) showed metastatic infiltration. The average size of 1067 tumor‐free lymph nodes was 5.1±3.8 mm in maximum diameter, whereas the average size of 129 metastatic lymph nodes was 6.7±4.2 mm (p=0.00006). Of all resected lymph nodes, 761 (63.6%) were ≤5 mm in maximum diameter. Only 9.3% (n=111) of all resected lymph nodes were >10 mm in maximum diameter. There was no significant correlation between lymph node size and the frequency of nodal metastases. No difference in size could be demonstrated between patients with and without neoadjuvant radiochemotherapy. Diagnostic imaging techniques using size as the criterion of nodal infiltration cannot exactly assess the nodal status of patients with esophageal carcinoma. This is also true for patients after neoadjuvant radiochemotherapy. Therefore, evaluation of the nodal status in patients with squamous cell carcinoma of the esophagus is entirely based on pathohistologic analysis after a well defined lymphadenectomy.
DNA index and S‐phase fraction in curative resection of colorectal adenocarcinoma: Analysis of prognosis and current trends
Authors: Chen Han‐Shiang , Sheen‐Chen Shyr‐Ming , Lu Chen‐Chang
Published: October 2002

The DNA index (DI) and S‐phase fraction (SPF) have been said to be independent factors in colorectal adenocarcinoma and have a different distribution from the clinicohistologic parameters. This study assesses the real efficacy of DI and SPF for curative resection of colorectal adenocarcinomas with respect to the prognosis and the clinicohistologic parameters. From July 1991 to October 1994 a total of 666 patients underwent curative resection of colorectal adenocarcinoma and DNA flow cytometry in Kaohsiung Chang Gung Memorial Medical Center Hospital, Taiwan. We defined diploid tumors as having a DI of τ; 0.9 but<1.1 and a nondiploid tumor as having a DI of <0.9 or >1.1. A high SPF was defined as being more than the median value for the total SPF. Altogether, 495 cases (74.32%) had a 5‐year cancer‐free survival. Tumor stage, DI, tumor location, and tumor morphology were associated with significant cancer‐free survival in the univariate analysis (p=0.0295,<0.001, 0.0357, and<0.001, respectively). After all factors were entered into the multivariate analysis, the independent factors for cancer‐free survival were found to be stage, tumor location, and morphology (p<0.001, 0.012, and 0.044, respectively). In cases distinguished by the DI, diploid tumors had significantly more frequent right colon locations (p<0.001). After cases were separated by the SPF (median value 18.4%), better histology (well differentiated adenocarcinoma) was noted with a low SPF (p=0.017). No other clinicohistologic parameters had significant differences shown by the DI or SPF. Thus DI and SPF failed to appear as independent factors for 5‐year cancer‐free survival. The independent factors for curative colorectal adenocarcinoma were tumor stage, location, and morphology. Diploid tumors were located at the right colon more often, and low SPF indicated better histology in the univariate analysis.
The connection between random sequences, everyday coincidences, and belief in the paranormal
Authors: Bressan Paola
Published: October 2002

This paper argues against the theory that people interpret unusual coincidences as paranormal because they misunderstand the probability of their occurring by chance. In the two studies reported here, 214 subjects were given a questionnaire on the frequency of coincidences in their lives, a series of probabilistic problems, and a scale assessing their belief in the paranormal. Believers reported more coincidences than disbelievers. Believers made more errors than disbelievers in tasks reflecting sensitivity to the relationship between expected distribution of chance events and total number of occurrences; and avoided repetitions of identical alternatives in a random sequence to a greater extent. However, the last two effects completely disappeared in a subsample of university students. It is proposed that a more frequent experience of coincidences, on the one hand, and a more biased representation of randomness, on the other, are independent consequences of a stronger propensity of believers in the paranormal to connect separate events. Copyright © 2002 John Wiley & Sons, Ltd.
Vividness of visual imagery and source memory for audio and text
Authors: Eberman Carolin , McKelvie Stuart J.
Published: October 2002

Two groups of high and low vivid imagers heard an audiotape of a crime, read an account of it with both correct and new information, then took recognition and source memory tests. While listening and reading, both groups were told to attend carefully, but one was also instructed to form visual images of the scene. Recognition memory accuracy was greater for material from the text only than from the audio only, whereas source memory accuracy was greater for audio than for text. For source memory of text, high imagers performed more poorly than low imagers under imagery instructions. These results replicate previous work and extend it from an initial film source to an audio source. Copyright © 2002 John Wiley & Sons, Ltd.
Teaching students to recognize structural similarities between statistics word problems
Authors: Quilici Jill L. , Mayer Richard E.
Published: October 2002

An important skill in mathematical problem solving is recognizing that the problem one is working on (target problem) can be solved using the same method as a problem one already knows (source problem). In a preliminary study, college students displayed a higher level of structural awareness (i.e. sorting word problems on the basis of structural features) at the end rather than the beginning of their first statistics course. In the main study, we taught college students to sort statistics word problems on the basis of structural features (i.e. whether the problem could be solved by t‐test, correlation, or chi‐square statistics) rather than surface features (i.e. the problem's cover story). These results support a structural awareness theory in which students learn to form problem schemas by abstracting the underlying structural features of a problem statement and organizing them into a generalized problem model. Copyright © 2002 John Wiley & Sons, Ltd.
A robust adaptive pole‐placement controller without strictly positive real condition
Authors: Xie Xuejun , Zhang Siying
Published: October 2002

This paper considers the adaptive pole‐placement control problem for system (1) with unmodelled dynamics ηn dominated by a small constant ε multiplied by a quantity independent of ε but tending to infinity as the past input, output, and noise grow. Using bounded external excitation and randomly varying truncation techniques, we give a design method of adaptive pole‐placement controller. It is shown that the closed‐loop system is globally stable, the estimation error for the parameter contained in the modelled part is of order ε, and the closed‐loop system under the adaptive pole‐placement control law is suboptimal in the sense of
$$\mathop{\lim\sup}\limits_{{n\to\infty }}{1\over n}\mathop{\sum}\limits_{i=0}^n{\left({A^{*}(z)y_{n}‐L(z)C(z)w_{n}‐B(z)R(z)y_{n}^{*}}\right)^{2}{\leq}O({\varepsilon}^{2})+\gamma^{2}\mathop{\sum}\limits_{j=1}^q{b_{j}^{2}}}$$\nopagenumbers\end
while the SPR condition used usually in other papers is replaced by a stability condition. Copyright © 2001 John Wiley & Sons, Ltd.
Platelet satellitism, spurious neutropenia, and cutaneous vasculitis: Casual or causal association?
Authors: Lazo‐Langner Alejandro , Piedras Josefa , Romero‐Lagarza Penélope , Lome‐Maldonado Carmen , Sánchez‐Guerrero Jorge , López‐Karpovitch Xavier
Published: October 2002

About 90 cases of platelet satellitism (PS) have been published, most of them involving neutrophils, a few comprising monocytes, and one case involving basophils. The case of a 30‐year‐old female patient with cutaneous vasculitis who developed asymptomatic severe neutropenia is reported. All blood smears (BS) prepared from peripheral blood samples collected with either ethylenediaminetetraacetic acid, trisodium citrate, and heparin showed PS involving neutrophils, eosinophils, and monocytes. Immunohistochemistry analysis of her skin biopsy and BS, employing peroxidase stain for the detection of antibodies directed against IgG, IgA, IgM, and C3, revealed an intense positive reaction only for IgG in the endothelium and leukocyte clumps within the microvasculature, as well as in peripheral blood neutrophils displaying the PS phenomenon. Transfer of the PS phenomenon was demonstrated by incubating the patient's plasma with leukocytes from an ABO‐compatible healthy donor. In our patient, PS did not disappear after incubation at 37°C, suggesting that this might be a different or “atypical” PS phenomenon probably mediated by an autoimmune process involving an IgG‐class antibody responsible for both conditions, PS, and cutaneous vasculitis. Am. J. Hematol. 70:246–249, 2002.© 2002 Wiley‐Liss, Inc.
Midsagittal facial soft‐tissue growth of French Canadian adolescents
Authors: Smith Shelley L. , Buschang Peter H.
Published: October 2002

This study examines changes in 12 midline soft‐tissue thicknesses from the forehead, nose, lip, and chin regions in girls and boys from 10 to 16 years of age. The soft‐tissue changes are compared to changes in two hard‐tissue distances (sella–nasion and nasion–menton). The subjects are from a mixed‐longitudinal sample studied at the Montreal Human Growth Research Center in the 1960s and 1970s. Total sample size is 242 (from lateral cephalographs of 124 males and 118 females), with numbers varying by age and measurement. For hard‐tissues, boys show clearly defined adolescent spurts, while girls display small velocity increases indicative of only very minor spurts. Forehead tissue thicknesses for both sexes change little and show no demonstrable growth spurts. For the nose and philtrum region, which have the greatest absolute soft‐tissue growth changes, both boys and girls show adolescent spurts. Peak velocities are attained between 13 and 14 years in boys and between 11.9 and 12.5 years in girls. Boys appear to have small adolescent spurts for upper (13.7 years) and perhaps lower lip thicknesses. Neither sex displays clear evidence for adolescent spurts in the chin region. Am. J. Hum. Biol. 14:457–467, 2002. © 2002 Wiley‐Liss, Inc.
Lung function of Han Chinese born and raised near sea level and at high altitude in Western China
Authors: Weitz Charles A. , Garruto Ralph M. , Chin Chen‐Ting , Liu Ji‐Chuan , Liu Rui‐Ling , He Xing
Published: October 2002

Forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), and FEV1/FVC ratios were determined for 531 individuals of Han Chinese descent living at low altitude (250 m) near Beijing and for 592 individuals of Han descent who were born and raised at three high altitudes (3,200 m, 3,800 m, 4,300 m) in Qinghai Province, P.R.C. The study included males and females, ages 6–51 years. Thorax widths, depths, and circumferences of Han females and males born and raised at high altitude are similar to those of low‐altitude Han. On the other hand, high‐altitude children and adolescents have larger relative sitting heights, indicating greater thorax lengths. After adjusting for this variation in morphology, mean FVC values among 6–21 year‐old Han at high altitude are only between 136 mL (for females) and 173 ml (for males) greater than those determined at low altitude but the differences are statistically significant and are maintained consistently throughout the growth period. These data indicate that growth at high altitude produces small‐to‐moderate increases in lung volumes (about 6%) relative to genetically similar groups growing up at low altitude. In addition, there is no evidence that lung volume growth is accelerated relative to morphological growth among Han children born and raised at high altitude. Adults, 22–51 years, also show greater FVC values at high altitude but the size of the increase relative to Han at low altitude is variable (3% in males and 11% in females). Greater lung function at high altitude is unlikely to result from increased activity or lower pollution, and thus appears to be primarily a result of development in a hypoxic environment. Differences in FVC and FEV1 at 3,200 m, 3,800 m, and 4,300 m are generally not significant, so that living at altitudes between 3,200 m and 4,300 m appears to have little additional effect on volumetric growth. Am. J. Hum. Biol. 14:494–510, 2002. © 2002 Wiley‐Liss, Inc.
An alternate characterization of hazard in occupational epidemiology: Years of life lost per years worked
Authors: Park Robert M. , Bailer A. John , Stayner Leslie T. , Halperin William , Gilbert Stephen J.
Published: October 2002

Background

Standardized mortality ratios (SMRs) and other measures of relative risk by themselves may not suffice as descriptors of occupational hazards for many audiences including decision‐makers and those at direct risk from hazardous work. To explore other approaches, we calculated excess years of potential life lost and excess lifetime risk for both lung diseases and fatal injuries in a cohort of uranium miners with historical records of exposure to radon gas.

Methods

We used relatively simple life table (SMR) methods and also analyzed lung cancer mortality with Poisson regression methods permitting control for smoking.

Results

Among uranium miners hired after 1950, whose all‐cause SMR was 1.5, 28 percent would experience premature death from lung diseases or injury in a lifetime of uranium mining. On average, each miner lost 1.5 yr of potential life due to mining‐related lung cancer, or almost 3 months of life for each year employed in uranium mining. As a consequence of all excess lung disease and injury risks combined, a year of mining was associated with 5.9 months loss of potential life. For each year actually working underground, miners lost more than 8 months of potential life. When controlled for smoking (and healthy worker effect) with Poisson regression, the estimates for radon‐related lung cancer effects were slightly larger. Although chronic disease deaths dominated in excess years of life lost (due to radon, silica and possibly other exposures), more years were lost on average per individual injury death (38 yr), than per excess lung cancer (20 yr) or other lung disease death (18 yr). Fatal‐injury dominated the potential years of life lost up to about age 40.

Conclusions

Years of life lost per years employed provides another, more intuitive summary of occupational mortality risk. Am. J. Ind. Med. 42:1–10, 2002. Published 2002 Wiley‐Liss, Inc.
Population‐based study of non‐infectious rhinitis in relation to occupational exposure, age, sex, and smoking
Authors: Hellgren Johan , Lillienberg Linnea , Jarlstedt Jan , Karlsson Göran , Torén Kjell
Published: October 2002

Background

Many types of occupational exposure are associated with the risk of non‐infectious rhinitis. We investigate the risk factors for this association.

Methods

A random population of 2,044 subjects (aged 21–51) answered a questionnaire that was comprised of detailed questions on occupational exposure, nasal complaints, and smoking. NIR was defined as the sensation of nasal blockage and/or attacks of sneezing without having a cold. The incidence rates for NIR among exposed and unexposed were calculated. In the different exposed groups, only NIR with onset after the start of exposure was regarded as exposed. If a subject reported NIR before the relevant exposure started, he/she was excluded from that analysis. Relative risks (RR) were calculated as incidence rate ratios. Odds ratios controlling for smoking, age, and atopy were also calculated.

Results

The incidence rate for NIR was 13.5/1,000 person‐years. Males exposed to fire fumes (RR 2.5, 95% confidence interval (CI) 1.5–4.1), women exposed to paper dust (RR 2.0, 95% CI 1.5–2.9), and male cleaners (RR 3.1, 95% CI 1.9–5.1) displayed an increased risk of developing NIR. Smoking was associated with an increased risk of NIR for both sexes.

Conclusion

Exposure to several occupational irritants is associated with a higher risk of developing NIR. Am. J. Ind. Med. 42:23–28, 2002. © 2002 Wiley‐Liss, Inc.
Process studies in genetic counseling: Peering into the black box
Authors: Biesecker Barbara B. , Peters Kathryn F.
Published: October 2002

Genetic counseling is a dynamic psychoeducational process. Yet we know very little about its interior. Process research explores what transpires between providers and their clients and can serve to provide insight into unknown practice dimensions. The few process studies that have been conducted in genetic counseling provide a glimpse into the Black Box, but more of this type of research is needed to examine the contents. To achieve success with process studies a contemporary definition of genetic counseling is proposed. Thoughtfully designed process studies in genetic counseling will provide the data to refine the definition and identify the components of counseling, the communication process between provider and client, the therapeutic interventions used by counselors, and the needs, attitudes and expectations of clients. Overall, process studies will contribute to a more accurate understanding of the practice of genetic counseling. Published 2001 Wiley‐Liss, Inc.
Categorizing genetic tests to identify their ethical, legal, and social implications
Authors: Burke Wylie , Pinsky Linda E. , Press Nancy A.
Published: October 2002

Practice standards in medical genetics provide an implicit guide to the ethical, legal, and social implications (ELSI) of genetic tests. The common use of nondirective counseling reflects the principle that many testing decisions should be determined by personal values. Yet geneticists make test recommendations in some circumstances, e.g., RET mutation testing for MEN2 and newborn screening for phenylketonuria (PKU). Conversely, many geneticists recommend against testing for Apolipoprotein E (ApoE) alleles to predict Alzheimer disease (AD) risk. Taken together, these examples suggest that genetic tests can be categorized by a joint consideration of clinical validity and availability of effective treatment for persons who test positive. For genetic tests with high clinical validity/no treatment (e.g., presymptomatic testing for Huntington disease), the predominant concern is adequate nondirective counseling to ensure an informed, autonomous decision. By contrast, the predominant concern for tests with high clinical validity/effective treatment (e.g., PKU) is assuring access to care for eligible persons. For tests with limited clinical validity/no treatment (e.g., ApoE), recommending against test use can be justified on the principle of avoiding harm. For a fourth category, tests with limited clinical validity/effective treatment (e.g., HFE mutation testing for hereditary hemochromatosis), net benefit is the issue: the balance between potential benefits of treatment and potential harms of genetic labeling must be weighed. Where uncertainty exists concerning both clinical validity and effectiveness of treatment, as in the case of BRCA1/2 mutation testing, the value of testing may vary according to different testing contexts. This approach to test categorization allows a rapid determination of the predominant ELSI concerns for different kinds of genetic tests and identifies the data most urgently needed for test evaluation. © 2001 Wiley‐Liss, Inc.
Paternal UPD14 is responsible for a distinctive malformation complex
Authors: Kurosawa Kenji , Sasaki Hiroyuki , Sato Yoshiaki , Yamanaka Michiko , Shimizu Mitsumasa , Ito Yuji , Okuyama Torayuki , Matsuo Mari , Imaizumi Kiyoshi , Kuroki Yoshikazu , Nishimura Gen
Published: October 2002

We present a boy and two girls with paternal uniparental disomy of chromosome 14q (patUPD14). One girl had a Robertsonian translocation, whereas two a normal karyotype. Based on the manifestations of these patients and four previously reported patients who all had translocated chromosome 14, The patUPD14 was thought to constitute a distinctive syndrome. The hallmarks included abdominal muscular defects, skeletal anomalies, and characteristic facies. The phenotype of patUPD14 was consistent with that of a previously reported mouse model, i.e., mouse embryos with paternal uniparental disomy of chromosome 12 that has a region orthologous to that of human chromosome 14. Dose effects of newly recognized imprinted genes on human chromosome 14q32, DLK1 and GTL2, could play an important role in the pathogenic mechanism of the distinctive malformation complex. © 2002 Wiley‐Liss, Inc.
Complete SHOX deficiency causes Langer mesomelic dysplasia
Authors: Zinn Andrew R. , Wei Fanglin , Zhang Ling , Elder Frederick F. , Scott Charles I. , Marttila Pia , Ross Judith L.
Published: October 2002

The SHOX (short‐stature homeobox‐containing) gene encodes isoforms of a homeodomain transcription factor important in human limb development. SHOX haploinsufficiency has been implicated in three human growth disorders: Turner syndrome, idiopathic short stature, and Leri‐Weill dyschondrosteosis. Langer mesomelic dysplasia is thought to be the homozygous form of dyschondrosteosis. However, complete SHOX deficiency has not been demonstrated for any postnatal patient with the classic Langer phenotype. We studied four adults and one child with Langer mesomelic dysplasia. SHOX abnormalities were detected in all five probands. One was a homozygote or hemizygote and two were compound heterozygotes. The homozygous or hemizygous mutation was in exon 6a, implying that the SHOXa isoform is essential for normal skeletal development. These findings confirm clinical inferences that Langer mesomelic dysplasia is the homozygous form of Leri‐Weill dyschondrosteosis and add to our understanding of genotype/phenotype relationships in SHOX deficiency disorders. © 2002 Wiley‐Liss, Inc.
Prevalence of the fragile X syndrome in African‐Americans
Authors: Crawford Dana C. , Meadows Kellen L. , Newman James L. , Taft Lisa F. , Scott Elizabeth , Leslie Mary , Shubek Lisa , Holmgreen Patricia , Yeargin‐Allsopp Marshalyn , Boyle Coleen , Sherman Stephanie L.
Published: October 2002

Since the development of a molecular diagnosis for the fragile X syndrome in the early 1990s, several population‐based studies in Caucasians of mostly northern European descent have established that the prevalence is probably between one in 6,000 to one in 4,000 males in the general population. Reports of increased or decreased prevalence of the fragile X syndrome exist for a few other world populations; however, many of these are small and not population‐based. We present here the final results of a 4‐year study in the metropolitan area of Atlanta, Georgia, establishing the prevalence of the fragile X syndrome and the frequency of CGG repeat variants in a large Caucasian and African‐American population. Results demonstrate that one‐quarter to one‐third of the children identified with the fragile X syndrome attending Atlanta public schools are not diagnosed before the age of 10 years. Also, a revised prevalence for the syndrome revealed a higher point estimate for African‐American males (1/2,545; 95% CI: 1/5,208–1/1,289) than reported previously, although confidence intervals include the prevalence estimated for Caucasians from this (1/3,717; 95% CI: 1/7,692–1/1,869) and other studies. Further population‐based studies in diverse populations are necessary to explore the possibility that the prevalence of the fragile X syndrome differs among world populations. © 2002 Wiley‐Liss, Inc.