Neuropilin-1 expression by tumor cells promotes tumor angiogenesis and progression

Neuropilin-1 (NRP1) is a VEGF(165) and semaphorin receptor expressed by vascular endothelial cells (EC) and tumor cells. The function of NRP1 in tumor cells is unknown. NRP1 was overexpressed in Dunning rat prostate carcinoma AT2.1 cells using a tetracycline-inducible promoter. Concomitant with increased NRP1 expression in response to a tetracycline homologue, doxycycline (Dox), basal cell motility, and VEGF(165) binding were increased three- to fourfold in vitro. However, induction of NRP1 did not affect tumor cell proliferation. When rats injected with AT2.1/NRP1 tumor cells were fed Dox, NRP1 synthesis was induced in vivo and AT2.1 cell tumor size was increased 2.5- to 7-fold in a 3-4 wk period compared to controls. The larger tumors with induced NRP1 expression were characterized by markedly increased microvessel density, increased proliferating EC, dilated blood vessels, and notably less tumor cell apoptosis compared to noninduced controls. It was concluded that NRP1 expression results in enlarged tumors associated with substantially enhanced tumor angiogenesis.

Measuring developmental outcomes of lead exposure in an urban neighborhood: the challenges of community-based research

The Developmental Research on Attention and Memory Skills (DREAMS) Project measures developmental outcomes of approximately 330 children at risk for lead exposure within an ethnically diverse, inner-city neighborhood. This study is one project of the Phillips Neighborhood Healthy Housing Collaborative, a 6-year-old collaboration between residents of the Phillips community in Minneapolis, university researchers, and representatives of various public and private agencies. Our experience carrying out this research is used to highlight both the benefits of, and the challenges to, measuring exposure outcomes in inner-city children using a community-based research approach. Challenges to working within a community collaborative, to studying an ethnically diverse and economically disadvantaged neighborhood, and to utilizing neighborhood residents as project staff are discussed. The strategies used to address these issues are presented to offer ideas for surmounting the challenges inherent in community-based research. The investigation of community environmental health problems through a community-based research approach can result in improved methodology, enhanced quality of data collected, and increased effectiveness of data dissemination. In addition, it can lead to important findings that inform the scientific community and create positive community changes. It is paramount, however, that potential obstacles be anticipated and planned for, or else be detected early and promptly responded to, in a manner that preserves scientific rigor while respecting community needs and values.

Movement sequencing in children with Tourette's syndrome and attention deficit hyperactivity disorder

Little research has been conducted to examine sequential motor functioning of children with Tourette's syndrome (TS) and attention deficit hyperactivity disorder (ADHD). Movement sequencing performance for a group of 12 children with TS and 24 children with ADHD children (12 taking and 12 not taking stimulant medication) and matched control subjects was examined using a serial choice reaction time button-pressing procedure. Aspects of movement preparation and execution were measured for 10 sequential two-way choice points along a response board that extinguished the illuminated target buttons at certain specific times contingent on the previous button press or release. The level of advance information was systematically reduced to provide three levels of reduction of advance information, including no reduction, moderate reduction, and high reduction. Children with TS and ADHD (unmedicated) showed larger increases in down time, reflecting aspects of movement preparation, for the highest level of reduction of advance information than did their respective control groups. These deficits are suggestive of underlying frontostriatal dysfunction. Furthermore, the normalization of performance for children with ADHD taking stimulant medication assists in the confirmation of the validity of such a clinical diagnosis and seems to add to the clinical efficacy of this form of treatment, which has previously been associated with improvements for predominantly attentional and inhibitory symptoms of ADHD.

Pretransplantation tumor necrosis factor-alpha production predicts acute rejection after liver transplantation

Immunosuppressive therapy has many adverse effects in both the short and longer term. Tailoring immunosuppression might be possible if pretransplantation parameters predicted rejection. We investigated production of the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), and the anti-inflammatory cytokine, interleukin-10 (IL-10), pretransplantation to determine whether there is a relation with acute rejection. Peripheral-blood mononuclear cells were obtained from patients with chronic liver disease on the waiting list for orthotopic liver transplantation and healthy controls. Cells (0.5 x 10(6)) were stimulated with 200 ng of lipopolysaccharide. Preincubation for 30 minutes with tacrolimus, cyclosporine, and dexamethasone at concentrations of 10 and 100 ng was also performed. TNF-alpha and IL-10 levels were measured by enzyme-linked immunosorbent assay. Acute rejection was defined on clinical and histological grounds. Pretransplantation in vitro production of TNF-alpha significantly (P <.05) increased in the group of patients with acute rejection (n = 9) compared with those who did not develop rejection (n = 12). Preincubation with dexamethasone significantly (P <.001) reduced TNF-alpha and IL-10 production in both patients and controls (n = 8). IL-10 production pretransplantation was not different in those who developed acute rejection (n = 9) compared with those who did not (n = 9). Preincubation with tacrolimus augmented (P <.05) the production of IL-10 in patients (n = 18), but not controls (n = 6). Pretransplantation TNF-alpha production is increased in patients who go on to develop acute rejection posttransplantion.

Questionnaire survey on management of spontaneous pneumothorax

INTRODUCTION

Management of spontaneous pneumothorax (SP) is variable and the initial management of SP is often undertaken by frontline junior medical staff.

OBJECTIVES

To assess if medical education in the principles of SP management is adequate and to determine if practice variability exists among different disciplines.

METHODS

A validated questionnaire survey on the knowledge and practice of the junior medical staff posted to a general hospital from May to December 1998 was performed. 138 doctors posted to the various departments: medical (n = S9), surgical (n = 46) and emergency (n = 33) were surveyed.

RESULTS

The response rate was 95%. 73% surveyed had experience inserting chest tubes (CT). Of the 27% (n = 37) who had never inserted CT, 41% were medical officers. Our results showed adequate knowledge pertaining to initial management of primary SP (PSP). The preferred site and method for CT insertion was the 5th intercostal space, anterior axillary line and open method. There was significant practice variability in the CT size, method of insertion and CT removal sequence among the disciplines (p < 0.05). However a significant proportion of staff (49%) chose to observe or aspirate an acutely breathless patient with a 10% secondary SP (SSP) instead of CT insertion.

CONCLUSION

While knowledge in PSP appears adequate, management of SSP and practical training in CT insertion must be emphasized as it is a simple procedure that is potentially life-saving.

Distressing emotions in female caregivers of people with AIDS, age-related dementias, and advanced-stage cancers

PURPOSE

To describe and compare the depressive mood, anxiety, anger, and sleep problems of informal female caregivers of people with AIDS, age-related dementias (ARD), and cancer (CA).

METHODS

Caregivers recruited from clinics serving people with AIDS, ARD, and CA were interviewed using structured instruments measuring depressive symptoms, anxiety, anger, and sleep problems. Data analysis compared these emotions in the caregivers and related aspects of the caregiving situation to these emotions within each group.

FINDINGS

Caregivers did not differ significantly in depressive mood, but did differ in anxiety and anger and sleep problems. Individual items on each scale were compared to provide more descriptive detail. In each group, distressing emotions were significantly related to each other and to sleep problems.

CONCLUSIONS

Caregivers of people with AIDS, ARD, and CA experience distressing emotions that may affect their mental and physical health. A comprehensive approach to mental health nursing therapy will best meet the needs of caregivers in relieving their distress.

The ultraviolet environment of Mars: biological implications past, present, and future

A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment, past and present. Biological action spectra for DNA inactivation and chloroplast (photosystem) inhibition are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Over time Mars has probably experienced an increasingly inhospitable photobiological environment, with present instantaneous DNA weighted irradiances 3.5-fold higher than they may have been on early Mars. This is in contrast to the surface of Earth, which experienced an ozone amelioration of the photobiological environment during the Proterozoic and now has DNA weighted irradiances almost three orders of magnitude lower than early Earth. Although the present-day martian UV flux is similar to that of early Earth and thus may not be a critical limitation to life in the evolutionary context, it is a constraint to an unadapted biota and will rapidly kill spacecraft-borne microbes not covered by a martian dust layer. Microbial strategies for protection against UV radiation are considered in the light of martian photobiological calculations, past and present. Data are also presented for the effects of hypothetical planetary atmospheric manipulations on the martian UV radiation environment with estimates of the biological consequences of such manipulations.

Deep-seated trichosporonosis in an immunocompetent patient: a case report of uterine trichosporonosis

We report an unusual case of endometritis caused by Trichosporon beigelii in an elderly woman who had no clinically obvious immunosuppression nor even clinically obvious skin disease. No evidence of predisposing factors for deep trichosporonosis was identified in this patient, who apparently is of normal immune status.

Confocal imaging of N-methyl-D-aspartate receptors in living cortical neurons

The fluorescence-conjugated N-methyl-D-aspartate receptor-selective antagonist, BODIPY-conantokin-G, was employed to label N-methyl-D-aspartate receptors in living neurons derived from the visual cortex of embryonic rats. The fluorescent labeling was visualized and analysed using confocal microscopy and digital imaging techniques. BODIPY-conantokin-G binding sites were homogeneously distributed across somata four days after neurons (E17-20) were placed in culture. In five-day-old cultures, BODIPY-conantokin-G binding sites became clusters of fluorescently labeled spots which were arranged irregularly on somata and proximal neurites. Distal neurites displayed fluorescent labeling after 10-15 days in culture. Displacement experiments showed that spermine and unlabeled conantokin-G compete with BODIPY-conantokin-G labeling at the N-methyl-D-aspartate receptor-associated polyamine site. The N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovaleric acid also depressed the labeling but with a weaker effect, probably due to interactions occurring between the N-methyl-D-aspartate receptor agonist binding site and the polyamine modulatory site. The fluorescent dyes FM 1-43 and FM 4-64 were used in double-labeling studies to compare the distribution of nerve terminals with that of BODIPY-conantokin-G binding sites. BODIPY-conantokin-G binding clusters were associated with presynaptic nerve terminals while isolated BODIPY-conantokin-G binding sites were not always opposed to terminals. The aggregation of receptors to form clusters may lead to the functional formation of excitatory synapses. To investigate whether modulation of membrane potentials affected the formation of N-methyl-D-aspartate receptor clusters, cultured neurons were chronically treated for a week with either tetrodotoxin (to block membrane action potentials) or a high concentration of potassium to depolarize the membrane. While neurons in the tetrodotoxin-treated group showed a similar number of fluorescently labeled clusters compared with the control group, neurons in the high potassium group exhibited a higher number of fluorescently labeled receptor clusters. These results suggest that more active neurons may tend to form more N-methyl-D-aspartate synapses during early development.

Conformational behavior of ionic self-complementary peptides

Several de novo designed ionic peptides that are able to undergo conformational change under the influence of temperature and pH were studied. These peptides have two distinct surfaces with regular repeats of alternating hydrophilic and hydrophobic side chains. This permits extensive ionic and hydrophobic interactions resulting in the formation of stable beta-sheet assemblies. The other defining characteristic of this type of peptide is a cluster of negatively charged aspartic or glutamic acid residues located toward the N-terminus and positively charged arginine or lysine residues located toward the C-terminus. This arrangement of charge balances the alpha-helical dipole moment (C --> N), resulting in a strong tendency to form stable alpha-helices as well. Therefore, these peptides can form both stable alpha-helices and beta-sheets. They are also able to undergo abrupt structural transformations between these structures induced by temperature and pH changes. The amino acid sequence of these peptides permits both stable beta-sheet and alpha-helix formation, resulting in a balance between these two forms as governed by the environment. Some segments in proteins may also undergo conformational changes in response to environmental changes. Analyzing the plasticity and dynamics of this type of peptide may provide insight into amyloid formation. Since these peptides have dynamic secondary structure, they will serve to refine our general understanding of protein structure.

Furosemide stimulates K transport in HCD57 erythroid cells

We examined the influence of serum and furosemide on K movement and cell volume in HCD57 cells, a murine erythroleukemia cell line, which require erythropoietin (EPO) for survival. We found that maintenance of cell volume depends on the concentration of serum in the culture medium. In isotonic medium containing 20% serum, HCD57 cells maintain their steady-state volume. In contrast, the cells shrink progressively as medium serum content is reduced. In serum-free medium, raising external K to 75 mm prevents cell shrinkage and a further increase in K to 145 mm results in swelling, revealing a role for K permeability in the regulation of cell volume. Of particular interest has been a serendipitous finding with furosemide. Below an external K concentration of 2.1 +/- 0.3 mm in medium containing 2% serum, furosemide inhibits K uptake, probably stemming from its well known inhibitory action on KCl cotransport. However, above that K concentration, furosemide stimulates K uptake in a dose-dependent manner. Moreover, furosemide potentiates cell shrinkage induced by serum withdrawal. These findings suggest that the transport machinery mediating cellular shrinkage, once primed by serum depletion, becomes receptive to a second stimulus.

Antiapoptotic herpesvirus Bcl-2 homologs escape caspase-mediated conversion to proapoptotic proteins

The antiapoptotic Bcl-2 and Bcl-x(L) proteins of mammals are converted into potent proapoptotic factors when they are cleaved by caspases, a family of apoptosis-inducing proteases (E. H.-Y. Cheng, D. G. Kirsch, R. J. Clem, R. Ravi, M. B. Kastan, A. Bedi, K. Ueno, and J. M. Hardwick, Science 278:1966-1968, 1997; R. J. Clem, E. H.-Y. Cheng, C. L. Karp, D. G. Kirsch, K. Ueno, A. Takahashi, M. B. Kastan, D. E. Griffin, W. C. Earnshaw, M. A. Veliuona, and J. M. Hardwick, Proc. Natl. Acad. Sci. USA 95:554-559, 1998). Gamma herpesviruses also encode homologs of the Bcl-2 family. All tested herpesvirus Bcl-2 homologs possess antiapoptotic activity, including the more distantly related homologs encoded by murine gammaherpesvirus 68 (gammaHV68) and bovine herpesvirus 4 (BHV4), as described here. To determine if viral Bcl-2 proteins can be converted into death factors, similar to their cellular counterparts, five herpesvirus Bcl-2 homologs from five different viruses were tested for their susceptibility to caspases. Only the viral Bcl-2 protein encoded by gammaHV68 was susceptible to caspase digestion. However, unlike the caspase cleavage products of cellular Bcl-2, Bcl-x(L), and Bid, which are potent inducers of apoptosis, the cleavage product of gammaHV68 Bcl-2 lacked proapoptotic activity. KSBcl-2, encoded by the Kaposi's sarcoma-associated herpesvirus, was the only viral Bcl-2 homolog that was capable of killing cells when expressed as an N-terminal truncation. However, because KSBcl-2 was not cleavable by caspases, the latent proapoptotic activity of KSBcl-2 apparently cannot be released. The Bcl-2 homologs encoded by herpesvirus saimiri, Epstein-Barr virus, and BHV4 were not cleaved by apoptotic cell extracts and did not possess latent proapoptotic activities. Thus, herpesvirus Bcl-2 homologs escape negative regulation by retaining their antiapoptotic activities and/or failing to be converted into proapoptotic proteins by caspases during programmed cell death.

Rabbit facial nerve regeneration in autologous nerve grafts after antecedent injury

OBJECTIVE

The effect of incomplete antecedent injuries on subsequent facial nerve regeneration within cable graft repairs is not known. The purpose of this study is to compare facial nerve regeneration after an immediate and delayed neural cable graft repair.

METHOD

Rabbit facial nerve regeneration after complete transectional injuries of the buccal division was compared in two experimental models. In one, a 10-mm segment of the nerve was transected, rotated 180 degrees, and immediately repaired as a cable graft (N=8). In the second, a preliminary nerve crush was allowed to recover over a 4-week period and a 10-mm segment of nerve centered on the crush site was then transected, rotated 180 degrees, and delay repaired as a cable graft (N = 7). Data are presented as total numbers of regenerating myelinated axons that traverse the surgical repair to innervate the cable graft and distal nerve stumps, as well as the percentage of regenerating neurites compared with preoperative pooled and individual controls. Subpopulations of regenerating neurons are delineated to quantify the pattern of neural innervation.

RESULTS

Five weeks after cable graft repair both groups had similar myelinated outgrowth from the proximal nerve stump across the proximal anastomosis to innervate the cable graft (3995 +/- 1209 vs. 3284 +/- 651; P = .89). However, the delayed repair group had more intrafascicular regeneration within cable grafts (2261 +/- 931 vs. 1660 +/- 1169; P = .02) and distal nerve stump (1532 +/- 281 vs. 445 +/- 120; P = .004) than the immediate repair group. The immediate repair group had greater extrafascicular nerve regeneration in the cable graft (2335 +/- 1954 vs. 437 +/- 236; P = .001) and more myelin and axonal debris in pre-existing neural fascicles of the cable graft (P = .02) and distal nerve stump (463 +/- 187 vs. 103 +/- 87; P = .02).

CONCLUSIONS

Antecedent priming lesions do not enhance axonal survival as determined by regenerating myelinated axonal counts. However, antecedent injuries enhance the efficiency of neural innervation of the affected mimetic musculature by increasing the number of myelinated intrafascicular neural regenerants in the cable graft and distal nerve stump. This is accomplished by two factors: increased perineural fibrosis and decreased intrafascicular myelin and axonal debris.

A case report of Aspergillus hypersensitivity syndrome with obstructing bronchial aspergillosis

INTRODUCTION

A 62-year-old Indian male with diabetes mellitus presented with atypical, overlap features of Aspergillus hypersensitivity syndrome and obstructing bronchial aspergillosis.

CLINICAL PICTURE

He was febrile and tachypnoeic with diffuse crepitations and wheezing. Chest X-ray was normal but eosinophil count was 2900/mm3 and Ig E > 10,000 IU/ml.

TREATMENT AND OUTCOME

He responded initially to high dose steroid therapy but deteriorated subsequently from extensive mucus plugging of the bronchial tree which resulted in respiratory failure and death. He was HIV-negative.

CONCLUSION

Culture and histologic examination of bronchoscopically identified tracheobronchial mucus plugs should be performed as early treatment may be life-saving.

A fragment of recombinant GABA(A) receptor alpha1 subunit forming rosette-like homo-oligomers

The type A gamma-aminobutyric acid (GABA(A)) receptor plays a major role in inhibitory synaptic transmission in the central nervous system. A fragment consisting of residues Cys166 to Leu296 of the alpha1 subunit of the GABA(A) receptor was overexpressed in Escherichia coli and was found to have stable beta-rich structures. Here, results from laser scattering, gel electrophoresis and electron microscopy demonstrated that this recombinant protein formed rosette-like homo-oligomers, mainly pentamers in solution. Therefore, the fragment apparently provides a valuable model system for studying the pentameric holoreceptor assembly. Non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis of the fragment showed that disulfide bonds formed between monomers contributed to the oligomerization of the fragment. The fact that this fragment alone could form pentamers in vitro strongly suggests that amino acid residues located within the Cys166-Leu296 region of the alpha1 subunit may contribute to the oligomerization of GABA(A) receptor in vivo.

Views of academic dentists about careers in academic dentistry in the United Kingdom

The aim of this paper is to report the views of academic dentists about careers in academic dentistry assessed by method of a postal questionnaire survey. The subjects of the survey were dentists in academic posts in the United Kingdom. The incentives in pursuing an academic career which respondents rated most highly were the opportunity to teach and the variety of work in an academic career. The greatest disincentives were competing pressures from service work, teaching and research, and the difficulty of getting research grants. Many would like to spend more time on research and less on service work and teaching. The length of time required for training, and the quality of training, was a concern, particularly for junior academics. Most respondents rated the enjoyment of their job highly but scored much lower on satisfaction with the time their job left for domestic and leisure activities. By contrast with academic medicine, in academic dentistry there is typically greater emphasis on teaching and less on research. In conclusion, the balance of activities in academic posts, particularly between service work, teaching and research, needs to be regularly reviewed. The development of a more structured training programme for junior academics, which does not disadvantage academic dentists when compared with their NHS colleagues, may be required.

Parity violation in elastic electron-proton scattering and the Proton's strange magnetic form factor

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92+/-0.61+/-0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.

Evaluation of molecular techniques to biotype Giardia duodenalis collected during an outbreak

Twenty-seven Giardia duodenalis cyst-positive specimens (human, animal, or drinking water) were obtained from a waterborne outbreak in a community in British Columbia, western Canada. Parasite isolates were characterized using molecular techniques at 4 different steps of organism retrieval. None of the drinking water samples (n = 20) infected gerbils and none was successfully amplified using polymerase chain reaction (PCR). We were able to genotype 4 of 7 (human and animal) isolates by amplification of DNA from original specimens at the triosephosphate isomerase (tpi) gene locus using PCR followed by restriction fragment length polymorphism (RFLP) analysis. Five of the original specimens inoculated into Mongolian gerbils (Meriones unguiculatus) were infective and genotyped at the tpi locus using parasite material collected from the gerbil (cysts and trophozoites). Pulsed field gel electrophoresis (PFGE) was used to biotype trophozoites collected from the gerbils as well as trophozoites from the 4 isolates that adapted to culture. Four of these 5 isolates displayed the same (designated outbreak) biotype at all parasite retrieval steps with all molecular techniques including the originally amplified isolates. PCR-RFLP identified an additional biotype group. The 4 isolates that adapted to in vitro culture were also characterized by isoenzyme electrophoresis (IE). Biotype groups identified in these axenized isolates were all the same with each molecular technique (PCR-RFLP, PFGE, IE) tested. Results of this study demonstrate a need for more sensitive molecular methods to detect and characterize Giardia in original host and environmental samples. Results are also consistent with evidence of biotype changes that occur during the presently used process of isolate retrieval.

Genomic structure of the human p47-phox (NCF1) gene

The cytosolic factor p47-phox, encoded by the NCF1 gene, is an essential component of the phagocyte NADPH-oxidase system. Upon activation of this multicomponent system, p47-phox translocates to the membrane and participates in the electron transfer from NADPH to molecular oxygen. A deficiency or absence of p47-phox is the most common autosomal form of chronic granulomatous disease (CGD). We have cloned and characterized the NCF1 gene from four bacteriophage clones, a P1 clone and genomic DNA from normal individuals. The gene is 15,236 base pairs long and includes 11 exons. It is 98.6% homologous in sequence to at least one pseudogene that maps to the same region of chromosome 7q11.23. Slightly more than half (50.37%) of the wild-type NCF1 gene consists of repetitive elements. In particular, the density of Alu sequences is high (1.4 Alu/kb); there are 21 Alu repeats interspersed through 10 introns. These findings are consistent with the observation that recombination events between the wild-type gene and its highly homologous pseudogenes account for the majority of potentially lethal mutations in p47-phox-deficient chronic granulomatous disease. Analysis of 1.96 kb of sequence 5' of the start of translation revealed a high homology (99.6%) between wild-type and pseudogene clones. Characterization of NCF1 establishes a foundation for detailed molecular analysis of p47-phox-deficient CGD patients as well as for the study of the regulation of the NCF1 gene and pseudogenes, both of which are present as full-length transcripts in normal individuals.

Publication bias in meta-analysis: its causes and consequences

Publication bias is a widespread problem that may seriously distort attempts to estimate the effect under investigation. The literature is reviewed to determine features of the design and execution of both single studies and meta-analyses leading to publication bias, and the role the author, journal editor, and reviewer play in selecting studies for publication. Methods of detecting, correcting for, and preventing publication bias are reviewed. The design of the meta-analysis itself, and the studies included in it, are shown to be important among a number of sources of publication bias. Various factors influence an author's decision to submit results for publication. Journal editors and reviewers are crucial in deciding which studies to publish. Various methods proposed for detecting and correcting for publication bias, though useful, all have limitations. However, prevention of publication bias by registering every trial undertaken or publishing all studies is an ideal that is hard to achieve.

Structural and metabolic characteristics of rhesus monkey m. soleus after spaceflight

The effect of microgravity and diminished motor activity on m. soleus fibers of rhesus monkeys was investigated. A significant size reduction of both slow- and fast-twitch fibers was found in the flight animals only. Also, total protein and capillary per fiber number were shown to decrease in the flight animals.