bluuebunny/crossref_metadata_2025 huggingface dataset:
Re‐utilization of Schwann cells during ingrowth of ventral root afferents in perinatal kittens
Authors: Nilsson Remahl A. Ingela M. , Masterman Thomas , Risling Mårten
Published: June 2008

Ventral roots in all mammalian species, including humans, contain significant numbers of unmyelinated axons, many of them afferents transmitting nociceptive signals from receptive fields in skin, viscera, muscles and joints. Observations in cats indicate that these afferents do not enter the spinal cord via the ventral root, but rather turn distally and enter the dorsal root. Some unmyelinated axons are postganglionic autonomic efferents that innervate blood vessels of the root and the pia mater. In the feline L7 segment, a substantial proportion of unmyelinated axons are not detectable until late in perinatal development. The mechanisms inducing this late ingrowth, and the recruitment of Schwann cells (indispensable, at this stage, for axonal survival and sustenance), are unknown. We have counted axons and Schwann cells in both ends of the L7 ventral root in young kittens and made the following observations. (1) The total number of axons detectable in the root increased throughout the range of investigated ages. (2) The number of myelinated axons was similar in the root's proximal and distal ends. The increased number of unmyelinated axons with age is thus due to increased numbers of small unmyelinated axons. (3) The number of separated large probably promyelin axons was about the same in the proximal and distal ends of the root. (4) Schwann cells appeared to undergo redistribution, from myelinated to unmyelinated axons. (5) During redistribution of Schwann cells they first appear as aberrant Schwann cells and then become endoneurial X‐cells temporarily free of axonal contact. We hypothesize that unmyelinated axons invade the ventral root from its distal end, that this ingrowth is particularly intense during the first postnatal month and that disengaged Schwann cells, eliminated from myelinated motoneuron axons, provide the ingrowing axons with structural and trophic support.
Histories and Memories in the Organisation and Struggles of the Santiago II Neighbourhood of El Alto, Bolivia
Authors: ARBONA JUAN MANUEL
Published: June 2008

This article analyses how relocated miners in the Santiago II neighbourhood of El Alto reframed their histories and their memories of struggle and organisation in the mining camps. It focuses on the ways in which residents organised the neighbourhood and how these histories and memories rose to the political surface during the time of crisis in October 2003.
From la guerra sucia to ‘A Gentleman’s Fight’: War, Disappearance and Nation in the 1976–1983 Argentine Dictatorship
Authors: SCORER JAMES
Published: June 2008

Analysing the last Argentine dictatorship in the light of contemporary re‐examinations of war, this article argues that the 1976–1983 dictatorship can be understood as a shift in war(s), from la guerra sucia to the Falklands/Malvinas conflict, from a limitless and unsustainable internal war to a bracketed external war. That external war is shown to be an attempt to re‐found a nation imploding through disappearance. Drawing on the history of disappearance in Argentina reveals that, despite obvious differences, there are many continuities between the dictatorship and other regimes, emphasising the dangers of a politics that encourages a nation ‘re‐malvinizada’.
The outcome of dimethylglyoxime testing in a sample of cell phones in Denmark
Authors: Thyssen Jacob Pontoppidan , Johansen Jeanne D. , Zachariae Claus , Menné Torkil
Published: June 2008

Background:  Nickel dermatitis may be caused by frequent and prolonged use of cell phones. Because little is known about the frequency of nickel release from cell phones, it is difficult to estimate the risk of nickel sensitization and dermatitis among their users.

Objective:  Inspired by a recent case of nickel dermatitis from prolonged cell phone use, the frequency of dimethylglyoxime (DMG)‐positive cell phones on the Danish market was investigated.

Methods:  Five major cell phone companies were contacted. Two were visited, and the DMG test was performed on a sample of their products.

Results:  5 of 15 (33.3%) phones from company A and 3 of 26 (11.5%) phones from company B showed at least 1 positive reaction. 3 phones had more than 1 positive DMG spots.

Conclusions:  This study documents that excessive nickel release (i.e. a positive DMG test) is relatively frequent in a sample of cell phones from the Danish market. Prolonged use of cell phones may in some cases fulfil the criteria for items included in the European Union Nickel Directive. We believe that this new cause of nickel dermatitis should be carefully followed and that regulatory steps may be necessary.
Decreasing trends in methyldibromo glutaronitrile contact allergy – following regulatory intervention
Authors: Johansen Jeanne D , Veien Niels , Laurberg Grete , Avnstorp Christian , Kaaber Knud , Andersen Klaus E , Paulsen Evy , Sommerlund Mette , Thormann Jens , Nielsen Niels H , Vissing Susanne , Kristensen Ove , Kristensen Berit , Agner Tove , Menné Torkil
Published: June 2008

Background:  The preservative methyldibromo glutaronitrile (MDBGN) has been banned, first from stay‐on, and later from rinse‐off cosmetics, in the EU countries because of increasing rates of contact allergy.

Objectives:  To evaluate the frequency of contact allergy to MDBGN among patients patch tested by the Danish Contact Dermatitis Group just before and following regulatory decisions.

Patients/Methods:  The data set comprised 19 279 consecutive eczema patients patch tested from 2003–2007 with MDBGN 0.3% in petrolatum (pet.) or, in a minority of patients, with Euxyl K™ 400 1.5% in pet.

Results:  A significantly decreasing trend in the frequency of positive patch tests to MDBGN was found from 4.6% in 2003 to 2.6% in 2007 (P < 0.001). The decreasing trend was seen for both men and women. A significantly decreasing proportion of cases with a current relevance of contact allergy to MDBGN was also seen from 51.3% in 2003 to 29% in 2007 (P < 0.001).

Conclusions:  Regulatory interventions have already had a major effect on allergic disease due to MDBGN in Denmark. The same trends are likely to be seen in other EU countries.
Parvovirus B19‐associated catastrophic endothelialitis with a Degos‐like presentation
Authors: Dyrsen Molly E. , Iwenofu O. Hans , Nuovo Gerard , Magro Cynthia M.
Published: June 2008

Parvovirus B19 is a single‐stranded DNA virus exhibiting affinity for a variety of cell types including endothelial cells. The basis of the affinity is globoside expression, the receptor for B19. B19 endothelial cell parasitism accelerates endothelial cell apoptosis, potentially critical in inducing neoantigenicity and secondary antibody formation. A 38‐year‐old previously healthy male developed intestinal and cutaneous infarction, elevated creatinine phosphokinase (CPK) levels and progressive cytopenias. The basis of his clinical presentation was unclear until a skin biopsy suggested a potential role for virally mediated endothelial cell injury. Hematoxylin and eosin, immunohistochemical, immunofluorescent and reverse transcriptase in situ polymerase chain reaction studies were conducted on skin biopsies to assess for viral triggers. B19 viremia and localization of B19 RNA transcripts to vascular endothelium were uncovered. A diagnosis of catastrophic endothelial cell injury attributable to B19 infection was rendered. The patient showed significant improvement with intravenous immunoglobulin (IVIG). Parvovirus B19 is a ubiquitous virus that in the majority of affected patients remains asymptomatic. Nevertheless, because of its ability to infect endothelium it can cause severe multiorgan endothelial cell injury.
Bullous lesions in acrodermatitis enteropathica delaying diagnosis of zinc deficiency: a report of two cases and review of the literature
Authors: Jensen Sarah L. , McCuaig Catherine , Zembowicz Artur , Hurt Mark A.
Published: June 2008

Acrodermatitis enteropathica (AE) is a rare disorder associated with poor absorption of zinc. A variety of clinical and histological findings have been reported in the literature, described mainly in isolated case reports. Because of the varied nature of these cases, the histological features of AE are described often as non‐specific. We describe lesions of AE in two patients who presented with vesiculobullous and erosive skin lesions, both showing intra‐epidermal, inflammatory vesiculation with surrounding eosinophilic epidermis and necrotic keratinocytes. The lack of clinical suspicion of AE led to their misdiagnosis. We present these two patients to further characterize the bullous variant of AE, and we review the previously reported clinical and histopathological findings.
Multiple Vacuoles in Plant Cells: Rule or Exception?
Authors: Frigerio Lorenzo , Hinz Giselbert , Robinson David G.
Published: June 2008

It is generally accepted that plant cells can contain multiple vacuoles with different functions, for example lytic vacuoles with lysosome‐like properties and protein storage vacuoles for reserve accumulation. Recent data call into question the generality of this theory. In this study, we review the published evidence for the existence of multiple vacuoles. We conclude that the multivacuole hypothesis is valid for a number of cases, but care should be taken before assuming that it applies universally.
Comparative Policy Brief: Status of Intellectual Disabilities in Jamaica
Authors: Thorburn Marigold J.
Published: June 2008

Abstract  A population‐based prevalence study in one region of Jamaica in 1987–1989 indicated that about 8% of the childhood population had cognitive (intellectual) disability. Some harmful beliefs and practices persist about child rearing, violence towards women, and child abuse of all types. A lack of knowledge is apparent about the efficacy of home‐based learning, rather than special schools or centers for children with disabilities. A national policy on the health, education, and protection of children is not fully implemented. There is also a national policy on disability, although there are few provisions for children aged 0–8 years. A ministerial policy on education for children with special needs is a work in progress. There are approximately 2,000 children aged 4–18 years in special education programs: It is not known how many are in inclusive educational settings. Although little information is available, it is likely that most adults with intellectual disabilities do not have any formal services after they leave school. Key issues for Jamaica are a need for more emphasis on early intervention, adult services, community‐based rehabilitation, professional training, and research on mild intellectual disability.
Non‐sutured fixation of cochlear implants using a minimally‐invasive approach
Authors: Loh C. , Jiang D. , Dezso A. , Fitzgerald O’Connor A.
Published: June 2008

Keypoints

The minimal invasive techniques have become the main stay of the surgical approach for the cochlear implant.

Securing the implant with sutures can be challenging due to the limited access and awkward operating angle.

We have developed a non‐sutured technique to secure the implant by placing and securing the proximal end of the electrode into a bony groove.

Our series supports the notion that the technique is suitable for implant cases in which the patient’s age is older than 18 months.
Angiogenesis and cell proliferation in nasal polyposis
Authors: Ahmed S.K. , Williams J.L. , Drake‐Lee A. , Egginton S.
Published: June 2008

Objectives.  Nasal polyposis has been proposed to be an angiogenic disorder. The aim of this study was to quantify the extent and type of angiogenesis in nasal polyposis.

Method.  Polyp and inferior turbinate biopsies were taken from each side of patients with bilateral polyposis. External control samples were taken from patients undergoing routine septorhinoplasty. None of the patients had any history of asthma, allergy or aspirin sensitivity. One set of samples was snap frozen, cryosectioned, and stained using fluorescent lectins (stains capillaries), Ki67 (stains proliferating nuclei) and DAPI (stains all nuclei). Capillary density, capillary associated proliferation indices, epithelial proliferation indices and stromal proliferation indices were all measured. Parallel sections were also stained for apoptosis using TUNEL staining. A second set of samples were formalin‐fixed and immersion stained for capillaries, then analysed in multiple orientations using confocal microscopy. Capillary fractional area, surface area, surface to volume ratio and mean diameter were measured.

Results.  There was no significant change from controls in capillary density, capillary‐associated proliferation, capillary fractional area, surface area or surface to volume ratio. Increases in stromal proliferation and apoptosis were seen in polyp samples.

Conclusions.  None of the commonly used measures of angiogenesis showed evidence of angiogenesis occurring in the polyp beyond that required for normal tissue growth. The architecture of the capillary bed is identical to the inferior turbinate tissue, hence angiogenesis is not a driving force in nasal polyposis. The previously reported presence of pro‐angiogenic growth factors may be involved in stromal proliferation and cell turnover.
The development of upper airway mucosal immune architecture depends on peri‐natal bacterial colonisation
Authors: Birchall M. , Inman C. , Laycock G. , Sait L. , Vandeimen P. , Rees L. , Cogan T. , Phillips A. , Burt R.I. , Mitchard L. , Ayling S.M. , Stokes C. , Humphrey T. , Stevens M. , Bailey M.
Published: June 2008

Background.  Mucosal immunity is incomplete at birth1,2 and may depend early exposure to bacteria.

Objectives.  Determine how early neonatal exposure to bacteria alters leukocytes in mammalian upper airways.

Method.  Five sows were delivered by Caesarean section into a sterile tent. Group A (n = 9) was maintained germ‐free. Others were colonised with Schaedler flora plus Staphylococcus (Group B, n = 6) or Bacillus (Group C, n = 5). In group A, two animals were killed at birth and two at 14 days. Remaining animals were killed at a median 24 days. CD4 (helper T‐cells), MHC II (monocytic cells) and CD16 (monocyte activation) expression was measured in upper airway mucosa by quantitative immunofluorescence histology.

Results.  CD4+ cells were rare in Group A, but increased significantly in colonised animals (GpB P = 0.004, GpC P = 0.018). In Group A, MHC II and CD16 expression was low and unaltered by age. Group B exhibited a significant increase in both antigens compared to Group A (MHC II P = 0.002; CD16 P = 0.017). Although higher, levels in Group C were statistically similar to Group A (MHC II P = 0.76, cd16 P = 0.883). There was significantly less co‐localisation of CD4+ cells with myeloid cells in Group A (P < 0.05).

Conclusions.  Normal development of upper airway mucosal immune architecture is dependent on the presence and content of its bacterial flora. Flora containing (aerobic) staphylococcus results in significantly greater acquisition of helper T‐cells and myeloid cells than that containing (anaerobic) Bacillus. There is evidence that the bacteria also affect the functional interaction between T‐cells and myeloid cells in the upper airway.

References. 1 (2007) Vet. immunol. immunopathol. 119, 243–253

2 (2005) Dev. comp. immunol. 29, 977–987
Pharmacologic suppression of MITF expression via HDAC inhibitors in the melanocyte lineage
Authors: Yokoyama Satoru , Feige Erez , Poling Laura L. , Levy Carmit , Widlund Hans R. , Khaled Mehdi , Kung Andrew L. , Fisher David E.
Published: June 2008

Melanoma incidence continues to rise at an alarming rate while effective systemic therapies remain very limited. Microphthalmia‐associated transcription factor (MITF) is required for development of melanocytes and is an amplified oncogene in a fraction of human melanomas. Microphthalmia‐associated transcription factor also plays an oncogenic role in human clear cell sarcomas, which typically exhibit melanoma‐like features. Although pharmacologic suppression of MITF is of potential interest in a variety of clinical settings, it is not known to contain intrinsic catalytic activity capable of direct small molecule inhibition. An alternative drug‐targeting strategy is to identify and interfere with lineage‐restricted mechanisms required for its expression. Here, we report that multiple histone deacetylase (HDAC)‐inhibitor drugs potently suppress MITF expression in melanocytes, melanoma and clear cell sarcoma cells. Although HDAC inhibitors may affect numerous cellular targets, we observed suppression of skin pigmentation by topical drug application as well as evidence of anti‐melanoma efficacy in vitro and in mouse xenografts. Consequently, HDAC inhibitor drugs are candidates to play therapeutic roles in targeting conditions affecting the melanocyte lineage.
Iris phenotypes and pigment dispersion caused by genes influencing pigmentation
Authors: Anderson Michael G. , Hawes Norman L. , Trantow Colleen M. , Chang Bo , John Simon W.M.
Published: June 2008

Spontaneous mutations altering mouse coat colors have been a classic resource for discovery of numerous molecular pathways. Although often overlooked, the mouse iris is also densely pigmented and easily observed, thus representing a similarly powerful opportunity for studying pigment cell biology. Here, we present an analysis of iris phenotypes among 16 mouse strains with mutations influencing melanosomes. Many of these strains exhibit biologically and medically relevant phenotypes, including pigment dispersion, a common feature of several human ocular diseases. Pigment dispersion was identified in several strains with mutant alleles known to influence melanosomes, including beige, light, and vitiligo. Pigment dispersion was also detected in the recently arising spontaneous coat color variant, nm2798. We have identified the nm2798 mutation as a missense mutation in the Dct gene, an identical re‐occurrence of the slaty light mutation. These results suggest that dysregulated events of melanosomes can be potent contributors to the pigment dispersion phenotype. Combined, these findings illustrate the utility of studying iris phenotypes as a means of discovering new pathways, and re‐linking old ones, to processes of pigmented cells in health and disease.
Induction of a Specific Strong Polyantigenic Cellular Immune Response after Short-Term Chemotherapy Controls Bacillary Reactivation in Murine and Guinea Pig Experimental Models of Tuberculosis
Authors: Guirado Evelyn , Gil Olga , Cáceres Neus , Singh Mahavir , Vilaplana Cristina , Cardona Pere-Joan
Published: June 2008

RUTI is a therapeutic vaccine that is generated from detoxified and liposomedMycobacterium tuberculosiscell fragments that has demonstrated its efficacy in the control of bacillus reactivation after short-term chemotherapy. The aim of this study was to characterize the cellular immune response generated after the therapeutic administration of RUTI and to corroborate the lack of toxicity of the vaccine. Mouse and guinea pig experimental models were infected with a low-doseM. tuberculosisaerosol. RUTI-treated animals showed the lowest bacillary load in both experimental models. RUTI also decreased the percentage of pulmonary granulomatous infiltration in the mouse and guinea pig models. This was not the case afterMycobacterium bovisBCG treatment. Cellular immunity was studied through the characterization of the intracellular gamma interferon (IFN-γ)-producing cells after the splenocytes' stimulation withM. tuberculosis-specific structural and growth-related antigens. Our data show that the difference between the therapeutic administration of BCG and RUTI resides mainly in the stronger activation of IFN-γ+CD4+cells and CD8+cells against tuberculin purified protein derivative, ESAT-6, and Ag85B that RUTI generates. Both vaccines also triggered a specific immune response against theM. tuberculosisstructural antigens Ag16kDa and Ag38kDa and a marked mRNA expression of IFN-γ, tumor necrosis factor, interleukin-12, inducible nitric oxide synthase, and RANTES in the lung. The results show that RUTI's therapeutic effect is linked not only to the induction of a Th1 response but also to the stimulation of a quicker and stronger specific immunity against structural and growth-related antigens that reduces both the bacillary load and the pulmonary pathology.
Characterization of Clonal Relatedness among the Natural Population of
Staphylococcus aureus
Strains by Using
spa
Sequence Typing and the BURP (Based upon Repeat Patterns) Algorithm
Authors: Mellmann Alexander , Weniger Thomas , Berssenbrügge Christoph , Keckevoet Ursula , Friedrich Alexander W. , Harmsen Dag , Grundmann Hajo
Published: June 2008

We evaluated the BURP (based upon repeat patterns) algorithm, which relies on sequencing of the
Staphylococcus aureus
protein A gene (
spa
), for its ability to infer clonal relatedness within a population of 110 wild-type strains. BURP clustering of the resulting 66
spa
types was highly concordant with multilocus sequence typing (96.5% concordance) and pulsed-field gel electrophoresis (94.9%).
Phenotypic and Molecular Characterization ofAcinetobacter baumanniiClinical Isolates from Nosocomial Outbreaks in Los Angeles County, California
Authors: Valentine Sonya C. , Contreras Deisy , Tan Stephanie , Real Lilian J. , Chu Sheena , Xu H. Howard
Published: June 2008

Multidrug-resistantAcinetobacter baumanniistrains have increasingly resulted in nosocomial outbreaks worldwide, leaving limited options for treatment. To date, little has been reported on the antimicrobial susceptibilities and genomic profiles ofA. baumanniistrains from hospital outbreaks in the Greater Los Angeles area. In this study, we examined the susceptibilities and genetic profiles of 20 nonduplicate isolates ofA. baumanniifrom nosocomial outbreaks in Los Angeles County (LAC) and determined their mechanisms of fluoroquinolone resistance. Antibiotic susceptibility testing indicated that the majority of these LAC isolates were not susceptible to 14 of the 17 antibiotics tested, with the exception of doxycycline, minocycline, and tigecycline. In particular, all isolates were found to be resistant to ciprofloxacin. Genomic DNA analysis revealed eight epidemiologically distinct groups among these 20A. baumanniiisolates, consistent with antibiotic susceptibility profiles. Sequencing analysis confirmed that concurrent GyrA and ParC amino acid substitutions in the “hot spots” of their respective quinolone resistance-determining regions were primarily responsible for the high-level ciprofloxacin resistance of these isolates. Antibiotic susceptibility testing using two efflux pump inhibitors suggested that the presence of efflux pumps was only a secondary contributor to ciprofloxacin resistance for some of the isolates. In summary, the present study has revealed good correlation between the antibiotic susceptibility profiles and genetic fingerprints of 20 clinical isolates from nosocomial outbreaks in Los Angeles County and has determined their mechanisms of fluoroquinolone resistance, providing an important foundation for continued surveillance and epidemiological analyses of emergingA. baumanniiisolates in Los Angeles County hospitals.
Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women
Authors: Church D. L. , Baxter Heather , Lloyd Tracie , Miller Beverley , Elsayed Sameer
Published: June 2008

The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of group B streptococcus (GBS) colonization status in near-term pregnant women (35 to 37 weeks of gestation) was evaluated. Dually collected vaginal/rectal swabs from 279 women enrolled from a single large maternity clinic were analyzed. Fifty (18%) women were colonized by GBS according to both methods. SCB had excellent diagnostic performance compared to LIM, with sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 100%, 100%, and 98.3%, respectively. Improved diagnostic efficiency due to direct reporting of GBS cases based on an orange color change in the SCB decreased overall labor and material costs.
Phenotypic and Genotypic Characterization of
Streptococcus pneumoniae
Strains Colonizing Children Attending Day-Care Centers in Norway
Authors: Vestrheim Didrik F. , Høiby E. Arne , Aaberge Ingeborg S. , Caugant Dominique A.
Published: June 2008

A cross-sectional study of nasopharyngeal colonization with
Streptococcus pneumoniae
was performed among 573 children attending 29 day-care centers (DCCs) in Norway prior to the start of mass vaccination with the heptavalent pneumococcal conjugate vaccine (PCV-7). A sensitive sampling method was employed, including transport in an enrichment broth and serotyping of pneumococci directly from the broth, in addition to traditional single-colony isolation from blood agar plates. The prevalence of carriage was high, peaking at 88.7% in 2-year-olds. More than one serotype was isolated from 12.7% of the carriers. Of 509 isolates obtained, 227 (44.6%) belonged to the PCV-7 serotypes. Penicillin nonsusceptibility was rare (1.8% of the isolates). Nonsusceptibility to erythromycin (5.9%), clindamycin (2.0%), and tetracycline (5.5%) was associated with PCV-7 serotypes (
P
< 0.001). Multilocus sequence typing was performed on the whole strain collection, revealing 102 sequence types (STs), of which 31 (30.4%) were novel. Eleven isolates (2.2%) belonged to the England
14
-9 clone, and 19 isolates (3.7%) belonged to, or were single-locus variants of, the Portugal
19F
-21 clone. The pneumococcal populations within the DCCs were composed of a majority of isolates with STs shared between the DCCs and a minority of isolates with STs unique for each DCC. The highest numbers of different STs, including novel STs, were found within the most frequent serotypes. Our study indicates that carriage of
S. pneumoniae
is highly prevalent among children in Norwegian DCCs, with a genetically diverse pneumococcal population consisting of unique microepidemic DCC populations.
Real-Time PCR Assays To Address Genetic Diversity among Strains ofMycoplasma hyopneumoniae
Authors: Strait Erin L. , Madsen Melissa L. , Minion F. Chris , Christopher-Hennings Jane , Dammen Matthew , Jones Katherine R. , Thacker Eileen L.
Published: June 2008

Mycoplasma hyopneumoniaeis an important cause of pneumonia in pigs around the world, but confirming its presence in (or absence from) pigs can be difficult. Culture for diagnosis is impractical, and seroconversion is often delayed after natural infection, limiting the use of serology. Numerous PCR assays for the detection ofM.hyopneumoniaehave been developed, targeting several different genes. Recently, genetic diversity among strains ofM.hyopneumoniaewas demonstrated. The effect of this diversity on the accuracy and sensitivity of theM.hyopneumoniaePCR assays could result in false-negative results in current PCR tests. In this study, a panel of isolates ofM.hyopneumoniae,M. flocculare,M. hyorhinis, andM. hyosynoviaewere tested with a number ofM.hyopneumoniae-specific PCR assays. SomeM.hyopneumoniaePCR assays tested did not detect all isolates ofM.hyopneumoniae. To increase the efficiency of PCR testing, two new real-time PCR assays that are specific and capable of detecting all of theM.hyopneumoniaeisolates used in this study were developed.
In Vivo Potential Effects of Adenovirus Type 5
E1A
and
E1B
on Lung Carcinogenesis and Lymphoproliferative Inflammation
Authors: Yang Yongping , McKerlie Colin , Lu Zhan , Wang Lena , Buchwald Manuel
Published: June 2008

Triggering uncontrolled cellular proliferation, chronic inflammation, and/or disruption of p53 activity is critical for tumorigenesis initiated by latent viral oncogenes. The adenovirus type 5 (Ad5) early genes
E1A
and
E1B
can maintain lifelong latency in the lungs of patients with chronic pulmonary diseases. To determine the in vivo effects of the latent Ad5
E1A
and
E1B
oncogenes, we have examined the influence of Ad5
E1A
and
E1B
gene products on mouse lung carcinogenesis and inflammation by generation and characterization of lung-specific transgenic mouse models. Here, we show that either the Ad5 E1A 243-amino-acid (aa) protein or the E1B 58-kDa protein was dominantly expressed in the transgenic lung. Preferential expression of Ad5 E1A 243-aa protein alone was not sufficient to induce lung carcinogenesis but resulted in low-grade cellular proliferation and high-grade lymphoproliferative inflammation in the lung. The presence of Ad5
E1B
dramatically enhanced the expression of the E1A 243-aa protein, in addition to impairing p53 and apoptosis response, resulting in uncontrolled cellular proliferation, lymphoproliferative inflammation, and metastatic carcinomas in the lung after a period of latency. Our studies may provide clues to understanding the potential in vivo biological effects of Ad5
E1A
and
E1B
latent in the lung and a new scope for assessing in vivo functions of viral genes latent in the infection target tissue.
Properties of Subviral Particles of Hepatitis B Virus
Authors: Chai Ning , Chang Ho Eun , Nicolas Emmanuelle , Han Ziying , Jarnik Michal , Taylor John
Published: June 2008

In the sera of patients infected with hepatitis B virus (HBV), in addition to infectious particles, there is an excess (typically 1,000- to 100,000-fold) of empty subviral particles (SVP) composed solely of HBV envelope proteins in the form of relatively smaller spheres and filaments of variable length. Hepatitis delta virus (HDV) assembly also uses the envelope proteins of HBV to produce an infectious particle. Rate-zonal sedimentation was used to study the particles released from liver cell lines that produced SVP only, HDV plus SVP, and HBV plus SVP. The SVP made in the absence of HBV or HDV were further examined by electron microscopy. They bound efficiently to heparin columns, consistent with an ability to bind cell surface glycosaminoglycans. However, unlike soluble forms of HBV envelope protein that were potent inhibitors, the SVP did not inhibit the ability of HBV and HDV to infect primary human hepatocytes.
Tegument Proteins of Human Cytomegalovirus
Authors: Kalejta Robert F.
Published: June 2008

Human cytomegalovirus (HCMV) is a common, medically relevant human herpesvirus. The tegument layer of herpesvirus virions lies between the genome-containing capsids and the viral envelope. Proteins within the tegument layer of herpesviruses are released into the cell upon entry when the viral envelope fuses with the cell membrane. These proteins are fully formed and active and control viral entry, gene expression, and immune evasion. Most tegument proteins accumulate to high levels during later stages of infection, when they direct the assembly and egress of progeny virions. Thus, viral tegument proteins play critical roles at the very earliest and very last steps of the HCMV lytic replication cycle. This review summarizes HCMV tegument composition and structure as well as the known and speculated functions of viral tegument proteins. Important directions for future investigation and the challenges that lie ahead are identified and discussed.
Surface, Planktonic, and Benthic Foraging by Juvenile Chinook Salmon (Oncorhynchus tshawytscha) in Turbid Laboratory Conditions
Authors: Gregory R. S. , Northcote T. G.
Published: June 2008

We investigated the effect of turbidity on the foraging behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) in the laboratory. We assessed visual ability by measuring the reaction distance of juvenile chinook to planktonic adult Artemia prey. Chinook exhibited a log-linear decline in reaction distance with increasing turbidity. These results were similar to those obtained by workers for other species. We also determined the effect of turbidity on the foraging rate of juvenile chinook for surface (Drosophila), planktonic (Artemia), and benthic (Tubifex) prey across a range of turbidity levels (< 1,18, 35, 70, 150, 370, 810 NTU). Foraging rates were reduced at higher turbidities for all three prey. However, for surface and benthic prey, foraging rates were also low in clear water, while highest rates were attained at intermediate turbidity levels (35–150 NTU). We suggest that increased feeding rate in turbid conditions reflects a reduced potential risk to predators.
Effect of Turbidity on the Predator Avoidance Behaviour of Juvenile Chinook Salmon (Oncorhynchus tshawytscha)
Authors: Gregory Robert S.
Published: June 2008

The effect of turbidity on the predator avoidance behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) was determined in controlled laboratory experiments. Bird and fish models were used to simulate predator risk. In the absence of risk, juvenile chinook were distributed randomly within an experimental arena in turbid conditions (≈23 NTU), but in clear conditions (<1 NTU) they associated with the bottom. When introduced to bird and fish predator models, the chinook altered their distribution and occupied deeper parts of the arena regardless of turbidity level. However, their responses in turbid conditions were less marked and of shorter duration. Turbidity apparently reduced the perceived risk of predation in juvenile chinook.
Geochemistry of Mercury in Two Hydroelectric Reservoirs in Quebec, Canada
Authors: Louchouarn Patrick , Lucotte Marc , Mucci Alfonso , Pichet Pierre
Published: June 2008

Carbon, nitrogen, phosphorus, and iron oxyhydroxide profiles were used to explain the retention of Hg in sediments of natural lakes and flooded soils in Quebec. In lake sediments, Hg levels increased from background concentrations of approximately 100 ng/g beneath the 10- to 16-cm depth interval to 150–490 ng/g near the surface. This increase was attributed to atmospheric inputs to the environment. In forest soils, the close association of Hg with the surficial organic horizon appears to be a potential source of contamination for the aquatic system through the transport of particulate matter by surface runoff. High organic matter content observed in the flooded soil of LG-2 Reservoir suggests that postsedimentation biodegradation is a slow process. In contrast, at Cabonga Reservoir, an 80% reduction in C, N, and Hg concentrations was observed between the flooded and the adjacent forest soil. Mechanical erosion processes (marling, waves, ice) rather than biodegradation seem responsible for the observed loss in C, N, and Hg. We propose that suspension of the humic horizon from flooded soils could constitute a significant source of Hg contamination to the overlying waters and biota until the exposed littoral zone stabilizes.
Movement Dynamics in a Fishery: Application of the Ideal Free Distribution to Spatial Allocation of Effort
Authors: Gillis Darren M. , Peterman Randall M. , Tyler Albert V.
Published: June 2008

Many traditional analyses of fisheries data assume that there is a negligible effect of alternative fish stocks on the spatial distribution of fishing effort and that the amount of local effort does not influence catchability. There is growing evidence that contradicts these assumptions. Because of the potential biases that these erroneous assumptions may cause in the interpretation of catch-per-unit-effort (CPUE) statistics, it is important to determine the factors governing the spatial distribution of effort in a fishery. We used data on the Hecate Strait, British Columbia, Canada, trawl fishery to test hypotheses about spatial allocation of effort and interaction among fishing vessels. The ideal free distribution of Fretwell and Lucas (1970. Acta Biotheor. 19: 16–36) was the foundation for deriving these tests. We found evidence for competition among vessels, although we could not distinguish whether the mechanism was interference or exploitation competition. As well, CPUE was generally equalized among the areas fished, as predicted by the ideal free distribution, because of movement of boats among areas. Thus, area-specific CPUE would not be a reliable index of relative abundance of fish in different areas; relative fishing effort may be better.
Colonization and decomposition of salal (Gaultheria shallon) leaf litter by saprobic fungi in successional forests on coastal British Columbia
Authors: Osono Takashi , Iwamoto Susumu , Trofymow John A.
Published: June 2008

The colonization of leaf litter by saprobic fungi was studied in old-growth and post-harvest successional Douglas-fir forests on southeast Vancouver Island, British Columbia. This study focused on leaf litter of salal ( Gaultheria shallon Pursh.), a dominant understory shrub in all stands. Salal litter is characterized by the occurrence of bleached portions attributable to fungal colonization of the litter and to the variable decomposition of recalcitrant compounds, such as lignin. Analyses of proximate chemical fractions, fungal assemblages on the bleached leaf area, and pure culture decomposition assays indicated that Marasmius sp. and Coccomyces sp. were responsible for rapid decomposition and bleaching of salal leaf litter. The bleached area accounted for 17%–22% of total area of salal leaf litter collected in immature (40–60 years old), mature (85–105 years old), and old-growth (more than 290 years old) stands, but for only 2% in regeneration (5–15 years old) stands. The reduction of bleached leaf area occupied by Marasmius sp. and Coccomyces sp. in regeneration stands could be due to the changes in microenvironmental conditions on the forest floor, in litter quality, or in food-web structure in soils. The decrease of fungi able to decay recalcitrant compounds may lead to a reduction of salal decomposition rates in clear-cut sites that would persist until canopy closure occurs.
The succinate:menaquinone reductase of Bacillus cereus — characterization of the membrane-bound and purified enzyme
Authors: García L.M. , Contreras-Zentella M.L. , Jaramillo R. , Benito-Mercadé M.C. , Mendoza-Hernández G. , del Arenal I.P. , Membrillo-Hernández J. , Escamilla J.E.
Published: June 2008

Utilization of external succinate by Bacillus cereus and the properties of the purified succinate:menaquinone-7 reductase (SQR) were studied. Bacillus cereus cells showed a poor ability for the uptake of and respiratory utilization of exogenous succinate, thus suggesting that B. cereus lacks a specific succinate uptake system. Indeed, the genes coding for a succinate–fumarate transport system were missing from the genome database of B. cereus. Kinetic studies of membranes indicated that the reduction of menaquinone-7 is the rate-limiting step in succinate respiration. In accordance with its molecular characteristics, the purified SQR of B. cereus belongs to the type-B group of SQR enzymes, consisting of a 65-kDa flavoprotein (SdhA), a 29-kDa iron–sulphur protein (SdhB), and a 19-kDa subunit containing 2 b-type cytochromes (SdhC). In agreement with this, we could identify the 4 conserved histidines in the SdhC subunit predicted by the B. cereus genome database. Succinate reduced half of the cytochrome b content. Redox titrations of SQR-cytochrome b-557 detected 2 components with apparent midpoint potential values at pH 7.6 of 79 and –68 mV, respectively; the components were not spectrally distinguishable by their maximal absorption bands as those of Bacillus subtilis . The physiological properties and genome database analyses of B. cereus are consistent with the cereus group ancestor being an opportunistic pathogen.
LOTKA–VOLTERRA TWO-SPECIES SYSTEM WITH PERIODIC INTERRUPTION OF COMPETITION
Authors: NAKAJIMA H. , YONEJIMA K. , MATSUOKA T. , SENO H.
Published: June 2008

We consider the two-species Lotka–Volterra competition system with a temporally periodic interruption of competition coefficient. We assume that the competition coefficient is constant in a time interval of fixed length τ+, while it is zero in the other time interval of length τ-. The temporal variation of the competition coefficient is rigorously periodic with period τ+ + τ-, in which the competition coefficient becomes a given positive constant and zero by turns, the other parameters being constant in time. We analyze the system analytically and numerically, and derive the condition for the permanence of the whole system, the coexistence of two competing species, and the change of the species-dominance in terms of the competition. We discuss some interesting natures of our system, distinguished from the original two-species Lotka–Volterra competition system with constant competition coefficients. The temporal interruption of competition could cause the change of the destiny of competing species.
NONLINEAR DYNAMICS NEAR THE CELL MEMBRANE OFCHARA CORALLINA
Authors: YU. PLYUSNINA T. , LAVROVA A. I. , PRICE C. B. , YU. RIZNICHENKO G. , RUBIN A. B.
Published: June 2008

The phenomenon of patterned distribution of pH near the cell membrane of the algae Chara corallina upon illumination is well-known. In this paper, we develop a mathematical model, based on the detailed kinetic analysis of proton fluxes across the cell membrane, to explain this phenomenon. The model yields two coupled nonlinear partial differential equations which describe the spatial dynamics of proton concentration changes and transmembrane potential generation. The experimental observation of pH pattern formation, its period and amplitude of oscillation, and also its hysteresis in response to changing illumination, are all reproduced by our model. A comparison of experimental results and predictions of our theory is made. Finally, a mechanism for pattern formation in Chara corallina is proposed.
STUDY OF EVOLUTION AND GROWTH VELOCITY OF VISCOUS FINGERING IN HELE SHAW CELL
Authors: SHAIKH YUSUF H. , KHAN A. R. , BEHERE S. H.
Published: June 2008

The study of the viscous fingering in Hele Shaw cell and the evolution of fingering pattern was presented and the growth velocity of pattern was determined. The fingers were recorded using a digital web camera. The movie frames were separated and the selected patterns were analyzed. The box counting technique was applied to the growth pattern and the Richardson plot technique was used for characterization of shapes in terms of structure and texture. The fingering patterns thus obtained in different frames were analyzed and the structural and textural analysis was presented. The scale invariance at different length scales was discussed.
MONTE CARLO SIMULATION OF SPIRAL GALAXY FORMATION
Authors: YOSHINO D. , SAGAWA H.
Published: June 2008

We perform the Monte Carlo simulation of the spiral galaxy formation by using a model which includes the effect of shockwave of supernova explosion in the stochastic process for the star formation. We analyze the fractal dimension of the spiral galaxy obtained by the two-point correlation function method. The calculated fractal dimensions are discussed in comparison with those of the present universe and the early universe. In our simulation, the fractal dimension is obtained as D ≈ 1.3, which is close to the value of the present universe.
SIERPIŃSKI PEDAL TRIANGLES
Authors: ZHANG XIN-MIN , HITT L. RICHARD , WANG BIN , DING JIU
Published: June 2008

We generalize the construction of the ordinary Sierpiński triangle to obtain a two-parameter family of fractals we call Sierpiński pedal triangles. These fractals are obtained from a given triangle by recursively deleting the associated pedal triangles in a manner analogous to the construction of the ordinary Sierpiński triangle, but their fractal dimensions depend on the choice of the initial triangles. In this paper, we discuss the fractal dimensions of the Sierpiński pedal triangles and the related area ratio problem, and provide some computer-generated graphs of the fractals.
Geomorphological evidence for a changing tectonic regime, Pasinler Basin, Turkey
Authors: COLLINS PHILIP E.F. , RUST DEREK J. , BAYRAKTUTAN M.SALIH
Published: June 2008

The Pasinler Basin, in the ‘East Anatolian Contractional Province’, features a suite of geomorphological zones, visible in the field, air photographs and Landsat and Shuttle Radar Topography Mission (SRTM) digital elevation model imagery. These zones reflect past and current tectonically influenced processes. Relicts of the Erzurum–Kars Plateau representing Mio-Pliocene volcanism, associated with transtensional tectonics, have been modified by two stages of drainage development: an earlier, shallow valley network, which was modified following uplift and tilting to form the present system characterized by deep narrow valleys that supply alluvial fan complexes. These fans discharge onto the present, aggradation-dominated basin floor. Initial normal faulting induced massive slope failures on the basin's northern margin. This extensional phase within the basin was reversed by the Late Pleistocene, with thrust faults modifying and producing landforms, and affecting sediment sequences, along both its northern and southern margins. The shift from a transtensional regime, and the associated volcanism, to normal faulting in the Pliocene to Early Pleistocene, and then to the present regime of compression-induced thrusting appears to correspond to a regional tectonic shift resulting from the collision of the Eurasian and Arabian plates and the subsequent westwards movement of the Anatolian microplate.
The structure and formation of mud volcano summit calderas
Authors: EVANS ROBERT J. , STEWART SIMON A. , DAVIES RICHARD J.
Published: June 2008

Circular depressions bounded by inward-dipping faults found at the upper terminations of large mud volcano systems (>500 m diameter) are termed ‘mud volcano summit calderas’. From new mapping and comparison with previously identified examples we describe a series of common structural and morphological features found at a number of calderas and propose a mechanism for caldera formation. A typical example consists of concentric deformational and volcanic zones including an outermost topographic rim, inward-dipping circular fault system, ‘moat’ and raised central ‘pedestal’ of freshly extruded mud volcanic sediment. This distinctive ‘moat and pedestal’ morphology can be explained in terms of the quantity and rheology of extruded mud, and appears characteristic of calderas from the South Caspian Basin and elsewhere. The association of fresh mud volcanic deposits with the calderas in combination with extensive literature on caldera modelling leads us to conclude that the most likely causal mechanism is subsidence as a result of evacuation of fluids and sediment from shallow structural levels during eruptions. Summit calderas mapped in this study characterize dormant periods of mud volcanism in subaerial and submarine settings, and appear to be a common structural element in the extrusive domain of mud volcano systems.