bluuebunny/crossref_metadata_2025 huggingface dataset:
Parent recommendations to support physical activity for families with young children: Results of interviews in deprived and affluent communities in South Wales (United Kingdom)
Authors: Khanom Ashrafunnesa , Evans Bridie Angela , Lynch Rebecca , Marchant Emily , Hill Rebecca A. , Morgan Kelly , Rapport Frances , Lyons Ronan A. , Brophy Sinead
Published: January 2020

Background

Physical inactivity is the fourth leading cause of mortality worldwide. Early childhood is a critical period when healthy behaviours can be instilled for a future active lifestyle. We explored community, societal and environmental factors affecting child and family physical activity and sought parent recommendations to support physical activity in families with young children.

Methods

We interviewed 61 parents expecting a child or with a baby ≤12 months (35 mother and father paired interviews and 26 interviews with mothers only). We purposively sampled families for neighbourhood deprivation status (Townsend Index; 26 affluent; 35 deprived). We conducted thematic analysis of interview transcripts using Bronfenbrenner's socio‐ecological framework to guide interpretation.

Results

We identified four themes: work family‐life balance; spaces for activity; beliefs and attitudes; and physical activity facilitators. We found that parents from deprived neighbourhoods were more likely to be underactive because of a complex web of community, social and personal factors which reduced motivation and hindered opportunity for physical activity. To increase knowledge and opportunity, respondents suggested ‘help not tell’ messages covering ‘why’, ‘how’ and ‘where’ information about physical activity, and using physical activity to support community engagement and social interaction.

Conclusions

Recommendations from parents highlight effective communication about the importance of early child and family physical activity and improved community access to safe facilities and opportunities. Both parents need to be engaged in designing interventions to support greater physical activity and healthy behaviours which are relevant and achievable in individuals’ lives.
Effects of preform structures on the mechanical and ablation properties of C/ZrC‐SiC composites
Authors: Yang Xiao‐Hui , Li Ke‐Zhi , Bai Long‐teng
Published: January 2020

In order to investigate the effects of preform structures on the mechanical and ablation properties of C/ZrC‐SiC composites, 3D4X, 3D5X and 3DZC C/ZrC‐SiC composites were fabricated with the same process. The mechanical and ablation properties of 3D4X, 3D5X, and 3DZC C/ZrC‐SiC composites were investigated. Results showed that the tensile strength (122.26 MPa) and bending strength (233.29 MPa) of 3D5X C/ZrC‐SiC composites were the largest, followed by the tensile strength (112.79 MPa) and bending strength (203.03 MPa) of 3DZC composites and the tensile strength (86.22 MPa) and bending strength (137.59 MPa) of 3D4X composites. The mechanical properties of C/ZrC‐SiC composites were mainly related to the fiber content in the axis direction and matrix compactness. In terms of ablation properties, 3DZC C/ZrC‐SiC composites acted out the worst performance (the linear ablation rates of 0.0293 mm/s and the mass ablation rates 0.00766 g/s), followed by 3D4X composites (the linear ablation rates of 0.0276 mm/s and the mass ablation rates 0.00683 g/s) and 3D5X composites (the linear ablation rates of 0.0175 mm/s and the mass ablation rates 0.00653 g/s), respectively, which were mainly due to the specific ablation angles, thermal conductivities, and ablation oxides contents caused by fiber volume fraction, braided angles, and other forming parameters.
A Contextual Analysis to Explore Barriers and Facilitators of Pain Management in Swiss Nursing Homes
Authors: Brunkert Thekla , Simon Michael , Ruppen Wilhelm , Zúñiga Franziska
Published: January 2020

Purpose

As part of a contextual analysis, this study aimed to generate a comprehensive understanding of barriers and facilitators to pain management in nursing homes to identify potential leverage points for future implementation studies.

Design

An explanatory sequential mixed‐methods study embedded in a cross‐sectional study in 20 Swiss nursing homes (data collection: July–December 2016).

Methods

Quantitative data were collected via care worker questionnaire surveys comprising 20 items assessing perceptions of barriers to pain management. Descriptive statistics were computed. In the subsequent qualitative strand we conducted four focus group discussions with care workers (registered nurses, licensed practical nurses, and nursing aides) using a knowledge‐mapping approach. Findings of both strands were merged and mapped onto domains of the Capability, Opportunity, and Motivation determine Behavior (COM‐B) system, a model for behavior, to identify determinants for behavior change.

Findings

Data from 343 completed care worker surveys (response rate 67.3%) and four focus groups with care workers were analyzed. Items rated most problematic were as follows: lack of availability of nonpharmacological treatment (60.9%), lack of application of nonpharmacological treatment (53.6%), reluctance of residents to report pain (51.1%), and lack of time for a comprehensive pain assessment (50.5%). Focus groups partly corroborated quantitative findings and complemented them with facilitators, such as close collaboration with physicians and further barriers (e.g., organizational factors such as high turnover and a lack of established routines in pain management).

Conclusions

Our approach using a behavioral model highlighted a need for implementation strategies that improve pain management knowledge and focus on motivational aspects to establish new routines and habits related to pain management among care workers.

Clinical Relevance

Our findings suggest that future approaches to improve pain management in nursing homes should go beyond provision of education and training. To establish new practices or adapt existing ones, a more complex approach (e.g., introduction of external or internal facilitators) is necessary to influence motivation and ultimately change behavior.
Grading of oral squamous cell carcinomas – Intra and interrater agreeability: Simpler is better?
Authors: Steigen Sonja E. , Søland Tine M. , Nginamau Elisabeth Sivy , Laurvik Helene , Costea Daniela‐Elena , Johannessen Anne Christine , Jebsen Peter , Bjerkli Inger‐Heidi , Uhlin‐Hansen Lars , Hadler‐Olsen Elin
Published: January 2020

Background

Numerous studies have been presented on histological grading of oral squamous cell carcinomas (OSCC) for predicting survival, but uncertainty of their usefulness rises due to discordances of results. A scoring system should be robust and well validated, and intra‐ and interrater agreement can be used as a tool to visualize the strength of reproducibility.

Methods

Here, we present an intra‐ and inter‐observer study on evaluation of OSCC using some of the most common histopathological parameters. The observers were from different Norwegian university hospitals, and calibration to ensure accuracy was first performed. Percentage of the agreement was calculated for the score made by the individual observer at different times, as well as between pairs of observers.

Results

The evaluation made by the same observer at two different time points (intrarater) correlated better than observations made by different participants (interrater). In an attempt to increase the rate of agreement, many of the parameters were either dichotomized into simply low‐ and high grade, or to a three‐tier system when more than three options in the original design. This increased the concurrence with 15.4% for the intrarater and with 23% for the interrater comparisons.

Conclusion

High agreement for histopathological parameters can be difficult to obtain on hematoxylin and eosin staining in scoring systems with many options. A simpler system might be more advantageous to achieve higher degree of reproducibility.
Oral granular cell tumour: A multicentric study of 56 cases and a systematic review
Authors: Lafuente Ibáñez de Mendoza Irene , López Ortega Karem , Trierveiler Marília , Oliveira Alves Monica Ghislaine , Dias Almeida Janete , Gándara Vila Pilar , Aguirre Urízar José Manuel , Pérez Sayans Mario
Published: January 2020

Objective

Granular cell tumour (GCT) is a benign neoplasm that originates from Schwann cells. Within the oral cavity, it usually appears as a lingual nodule and especially amongst female adults. Histologically, GCT shows a proliferation of polygonal cells with eosinophilic granular cytoplasm, which can be associated with a pseudoepitheliomatous hyperplasia (PEH). In this study, we analyse the main clinicopathological data of intraoral GCT and we compare our results with previous studies.

Material and Methods

We have studied a series of 56 cases of oral GCT in Spain and Brazil, and we have conducted a systematic review in PubMed, Web of Knowledge and Scopus databases, using the keywords: “granular cell tumour” and oral.

Results

In our series, GCT appeared as an asymptomatic benign tumour that is more frequent in women and in the tongue. PEH was observed in 32% of the lesions. In the review, we collected 282 cases of oral GCT with a similar clinical profile; seven patients had multiple lesions, and 33% of the cases presented PEH. No cases of malignant oral GCT have been described to date. GCT is an uncommon oral benign neoplasm, mainly unique and asymptomatic, derived from Schwann cells.

Conclusions

Although the etiopathogenesis of this oral tumour is unknown, its characteristics suggest that it could have a reactive nature. Conducting a complete clinicopathological study in all intraoral GCT is fundamental in order to dismiss other entities, including oral carcinoma.
A mycorrhiza‐specific H+‐ATPase is essential for arbuscule development and symbiotic phosphate and nitrogen uptake
Authors: Liu Junli , Chen Jiadong , Xie Kun , Tian Yuan , Yan Anning , Liu Jianjian , Huang Yujuan , Wang Shuangshuang , Zhu Yiyong , Chen Aiqun , Xu Guohua
Published: January 2020

Most land plants can form symbiosis with arbuscular mycorrhizal (AM) fungi to enhance uptake of mineral nutrients, particularly phosphate (Pi) and nitrogen (N), from the soil. It is established that transport of Pi from interfacial apoplast into plant cells depends on the H+ gradient generated by the H+‐ATPase located on the periarbuscular membrane (PAM); however, little evidence regarding the potential link between mycorrhizal N transport and H+‐ATPase activity is available to date. Here, we report that a PAM‐localized tomato H+‐ATPase, SlHA8, is indispensable for arbuscule development and mycorrhizal P and N uptake. Knockout of SlHA8 resulted in truncated arbuscule morphology, reduced shoot P and N accumulation, and decreased H+‐ATPase activity and acidification of apoplastic spaces in arbusculated cells. Overexpression of SlHA8 in tomato promoted both P and N uptake, and increased total colonization level, but did not affect arbuscule morphology. Heterogeneous expression of SlHA8 in the rice osha1 mutant could fully complement its defects in arbuscule development and mycorrhizal P and N uptake. Our results propose a pivotal role of the SlHA8 in energizing both the symbiotic P and N transport, and highlight the evolutionary conservation of the AM‐specific H+‐ATPase orthologs in maintaining AM symbiosis across different mycorrhizal plant species.
Cognitive illness representation and anxiety in older men and women with type 2 diabetes
Authors: Zawadzka Ewa , Domańska Łucja
Published: January 2020

Aim

In the elderly, type 2 diabetes is a frequent chronic condition that requires the attention of health care. As patient involvement is a prerequisite for treatment, it seems crucial to assess psychosocial aspects, including patient's cognitive component of attitude towards the condition, as early as upon diagnosis. The aim of this study was to examine whether the cognitive illness representation in older female and male patients with type 2 diabetes is differentiated. Considering disease duration, we determined the effect of cognitive illness representation on older diabetes emotional wellbeing.

Methods

The study in 99 older adults with type 2 diabetes used Disease‐Related Appraisals Scale (Skala Oceny Własnej Choroby; SOWCh) to assess cognitive illness representation and State–Trait Anxiety Inventory (STAI) to assess the severity of state anxiety.

Results

In a subgroup with short‐standing diagnosis, women scored significantly higher than men on subscales of Threat, Obstacle/Loss and Profit. In a subgroup with long‐standing diagnosis, women scored significantly higher than men on the subscale of Threat and significantly lower than men on the subscale of Value. The associations between the individual dimensions of cognitive illness representation and anxiety were also determined. These correlations differed between sexes and stages of the disease.

Conclusion

Both at early and late stages of type 2 diabetes, women perceive their illness as a threat significantly more than men do. This appraisal persists throughout the entire duration of the illness. Men with long‐standing diagnosis, attribute higher value to diabetes than women do, perceiving it as an opportunity to appreciate values they did not pay attention to before. Anxiety reported by older women and men can be explained to a significant extent by certain dimensions of their respective cognitive illness representation.
Achieving equity in dialysis care and outcomes: The role of policies
Authors: Crews Deidra C. , Novick Tessa K.
Published: January 2020

Socially disadvantaged persons, including racial and ethnic minorities, individuals with low incomes, homeless persons, and non‐US citizens bear a disproportionate burden of end‐stage kidney disease (ESKD). Inequities in nephrology referral, vascular access, use of home dialysis modalities, kidney transplantation, and mortality are prominent. Public policies, including the Patient Protection and Affordable Care Act, end‐stage renal disease Quality Incentive Program, and the Prospective Payment System, were enacted to improve healthcare access and dialysis care. Here, we highlight inequities in dialysis care and outcomes, how current ESKD and other public policies may influence or exacerbate these inequities, and gaps in the literature needed to inform future policies toward achieving equity in ESKD. We give special attention to the 2019 Advancing American Kidney Health Executive Order, which has high potential to radically transform dialysis care.
A Resource‐Rational, Process‐Level Account of the St. Petersburg Paradox
Authors: Nobandegani Ardavan S. , Shultz Thomas R.
Published: January 2020

The St. Petersburg paradox is a centuries‐old philosophical puzzle concerning a lottery with infinite expected payoff for which people are only willing to pay a small amount to play. Despite many attempts and several proposals, no generally accepted resolution is yet at hand. In this work, we present the first resource‐rational, process‐level explanation of this paradox, demonstrating that it can be accounted for by a variant of normative expected utility valuation which acknowledges cognitive limitations. Specifically, we show that Nobandegani et al.'s (2018) metacognitively rational model, sample‐based expected utility (SbEU), can account for major experimental findings on this paradox. Crucially, our resolution is consistent with two empirically well‐supported assumptions: (a) People use only a few samples in probabilistic judgments and decision‐making, and (b) people tend to overestimate the probability of extreme events in their judgment. Our work seeks to understand the St. Petersburg gamble as a particularly risky gamble whose process‐level explanation is consistent with a broader process‐level model of human decision‐making under risk.
Innovation from Anywhere
Authors: Costabile Thomas
Published: January 2020

The idea that innovation could come from anywhere is apparent in the 2019 Mechanical Engineering Magazine Emerging Technology Awards. The awards are in their third year now and celebrate technologies that have left the R&D phase, passed through the precommercialization “valley of death,” and have begun to make an impact on the marketplace.
Recycling Robots
Authors: Gibson Tom
Published: January 2020

Robots have functioned for years on assembly lines, such as in automotive plants, where they perform the same task repetitively. This article explores how companies are coupling robotics with artificial intelligence in order to allow them to make the kinds of judgements needed in sorting recyclables. It isn’t the kind of high-profile task normally associated with machine learning, such as driving automobiles or finding cancerous growths in medical scans, but it could save recycling companies money.
High School Student Fitness Test Attributions: Does BMI or Performance Matter?
Authors: Davis Summer , Zhu Xihe , Haegele Justin
Published: January 2020

Purpose: To examine differences in fitness test performance and the attributions made for the performances between high school students of different weight status. Methods: High school students (n = 185) completed the Progressive Aerobic Cardiovascular Endurance Run and the push-up fitness tests and then completed the modified Causal Dimension Scale to assess their attributions for their performances. Results: Students of a healthy weight performed higher than overweight/obese students on both fitness tests. There were no significant differences in attribution dimension scores for either test between healthy weight and overweight/obese students. Student performance played a significant role on the attribution dimension scores for both tests. Students primarily attributed their push-up and Progressive Aerobic Cardiovascular Endurance Run performance to ability. Conclusion: As student performance is significantly associated with attribution dimension scores, improving fitness test performance should subsequently foster adaptive attributions, creating a high expectancy for future success.
Global polio eradication falters in the final stretch
Authors: Roberts Leslie
Published: January 2020

Vaccine-derived outbreaks may force a change in "endgame" strategy.
Strain Variability of
Listeria monocytogenes
under NaCl Stress Elucidated by a High-Throughput Microbial Growth Data Assembly and Analysis Protocol
Authors: Aalto-Araneda Mariella , Pöntinen Anna , Pesonen Maiju , Corander Jukka , Markkula Annukka , Tasara Taurai , Stephan Roger , Korkeala Hannu
Published: January 2020

The pathogen
Listeria monocytogenes
causes the foodborne disease listeriosis, which can be fatal in immunocompromised individuals.
L. monocytogenes
tolerates several environmental stressors and can persist in food-processing environments and grow in foodstuffs despite traditional control measures such as high salt content. Nonetheless,
L. monocytogenes
strains differ in their ability to withstand stressors. Elucidating the intraspecies strain variability of
L. monocytogenes
stress tolerance is crucial for the identification of particularly tolerant strains. To enhance reliable identification of variability in bacterial stress tolerance phenotypes, we compiled a large-scale protocol for the entire data assembly and analysis of microbial growth experiments, providing a systematic approach and checklist for experiments on strain-specific growth ability. Our study illustrated the diversity and strain-specific variation of
L. monocytogenes
stress tolerance with an unprecedented scope and discovered biologically relevant serovar- and lineage-dependent phenotypes of NaCl tolerance.
Wolbachia
Endosymbiont of the Horn Fly (Haematobia irritans
irritans
): a Supergroup A Strain with Multiple Horizontally Acquired Cytoplasmic Incompatibility Genes
Authors: Madhav Mukund , Parry Rhys , Morgan Jess A. T. , James Peter , Asgari Sassan
Published: January 2020

Horn flies,
Haematobia irritans irritans
, are obligate hematophagous parasites of cattle having significant effects on production and animal welfare. Control of horn flies mainly relies on the use of insecticides, but issues with resistance have increased interest in development of alternative means of control.
Wolbachia pipientis
is an endosymbiont bacterium known to have a range of effects on host reproduction, such as induction of cytoplasmic incompatibility, feminization, male killing, and also impacts vector transmission. These characteristics of
Wolbachia
have been exploited in biological control approaches for a range of insect pests. Here we report the assembly and annotation of the circular genome of the
Wolbachia
strain of the Kerrville, TX, horn fly (
w
Irr). Annotation of
w
Irr suggests its unique features, including the horizontal acquisition of additional transcriptionally active cytoplasmic incompatibility loci. This study provides the foundation for future studies of
Wolbachia
-induced biological effects for control of horn flies.
Biochemical and Immunological Effects of
Listeria monocytogenes
Hemolysin
Authors: Kingdon G. Charles , Sword C. P.
Published: January 2020

The biochemical and immunological effects of
Listeria monocytogenes
hemolysin in CD-1 mice were studied. Intraperitoneal injection of 256 complete hemolytic units (CHU) caused a twofold increase in plasma β-glucuronidase levels but was not lethal. In contrast, 256 or more CHU caused 100% lethality in 4 to 5 min when administered intravenously. Intravenous administration of 50 CHU caused a 10- to 11-fold increase in plasma β-glucuronidase levels and was lethal for a variable percentage of the animals. Carbon clearance experiments showed the phagocytic index to be depressed by relatively small amounts of intravenously administered hemolysin and suggested that hemolysin may function as a leucocidal agressin during listeric infection. Increased plasma levels of ornithine carbamyltransferase after intravenous injection of hemolysin indicated hepatocellular damage. Liver carbohydrate and blood glucose determinations on fasted mice showed a reduced gluconeogenic capability in hemolysin-treated animals. Mice immunized with purified hemolysin or live vaccine were more resistant to several of the toxic parameters studied. The data indicate that hemolysin is produced during listeric infection and is antigenic, but not necessarily a protective immunogen.
Reversal of Penicillin-Induced L-Phase Growth of
Haemophilus influenzae
by Spermine and Its Effects on Antibiotic Susceptibility
Authors: Lapinski E. M. , Flakas E. D.
Published: January 2020

Spermine at a concentration of 0.001
m
initiated the reversion of penicillin-induced L-phase growth of
Haemophilus influenzae
to bacillary growth on penicillin L-phase medium. Reversion of L-phase colonies to bacillary colonies required 3 to 5 days. This spermine reversal of variant growth also occurred on penicillin induction medium in the presence of concentrations of tetracycline, erythromycin, and chloramphenicol that were not bactericidal for L-phase or bacillary inocula until 48 or more hr. Spermine was without protective effect against streptomycin and kanamycin, which were, in combination with penicillin, bactericidal at 24 hr. Spermine protection of L-phase variants against antibiotic toxicity was, therefore, related to initiation (by spermine) or bacillary growth from round bodies that survived for 24 or more hr at bacteriostatic levels of antibiotic.
Effect of Bactericidal Substance from
Staphylococcus aureus
on Group A Streptococci II. Structural Alterations
Authors: Clawson C. Carlyle , Dajani Adnan S.
Published: January 2020

Ultrastructural alterations brought about by treatment of a β-hemolytic streptococcus with a bactericidal substance from
Staphylococcus aureus
are described and illustrated. The substance causes an early condensation of nucleoid deoxyribonucleic acid (DNA) and a partial loss of ribosomes. These changes are followed by a dissolution of the cell contents resulting in bacterial “ghosts” composed of empty cell wall and capsule. These morphological findings correlate with known biochemical effects of the bactericidal substance on ribonucleic acid degradation and cessation of DNA and protein synthesis.
Recovery and Characterization of a Minute Virus of Canines
Authors: Binn L. N. , Lazar E. C. , Eddy G. A. , Kajima M.
Published: January 2020

Four antigenically related transmissible agents were recovered from canine fecal specimens. The agents produced cytopathic effects in a continuous dog cell line developed in this laboratory. Increased antibody titers were demonstrated in three of the four dogs which provided the isolates. The virus did not produce cytopathic effects in primary canine kidney or thymus cell cultures, or in cell cultures of human, simian, porcine, bovine, feline, and murine origin. The agent is resistant to ether, chloroform, and heat treatment, and the growth of the virus is inhibited by 5-iodo-2-deoxyuridine. After acridine orange staining, green fluorescent intranuclear inclusions are seen in infected cell cultures. By electron microscopy, the virions measure approximately 20 to 21 nm in overall diameter and are present in the nuclei of infected cells. These properties are consistent with membership in the parvovirus or picodnavirus group. The agent hemagglutinates rhesus red blood cells at 5 C and by hemagglutination-inhibition tests could be readily distinguished from H-1, rat virus, and the minute virus of mice. Canine gamma globulin contains high titers of neutralizing antibody and neutralizing antibody was found in a high percentage of military dogs and in beagles of a breeding colony.
Utilization of Amino Acids During Growth of
Mycobacterium tuberculosis
in Rotary Cultures
Authors: Lyon Richard H. , Hall Wendell H. , Costas-Martinez Carlos
Published: January 2020

Marked differences were observed in the response of actively growing cells of the saprophyte,
Mycobacterium smegmatis
607, and the avirulent human strain,
M. tuberculosis
(H37Ra), to several different nitrogen sources in aerated (rotary) cultures. The growth-promoting effect and utilization of equimolar concentrations (5 μmoles/ml) of
l
-alanine,
l
-aspartic acid, monosodium glutamate, or ammonium chloride were compared with that of
l
-asparagine, the normal nitrogen source, in Sauton synthetic liquid medium. The saprophyte grew equally well with each nitrogen source. However, marked differences were seen with H37Ra. Based on the rate of growth and cell yield, the relative growth-promoting effect of the amino acids for H37Ra is: alanine ≫ glutamate > asparagine > aspartic. Utilization of alanine, glutamate, and aspartic correlated well with growth. In contrast, utilization of asparagine during early growth of H37Ra was severalfold greater than that of either alanine or glutamate. Extracellular amino acids accumulated during the metabolism of asparagine but not during the utilization of the other nitrogen sources. Balanced metabolism of asparagine does not take place during aerated growth of H37Ra in asparagine media. During the metabolism of
l
-asparagine by
M. tuberculosis
(H37Ra) in aerated liquid cultures, metabolic controls may be exerted which impede protein synthesis.
Cryptococcus neoformans
IV. The Not-So-Encapsulated Yeast
Authors: Farhi Fereshteh , Bulmer G. S. , Tacker J. R.
Published: January 2020

Nonencapsulated cells of
Cryptococcus neoformans
which may have a diameter of less than 4 μm are capable of producing experimental cryptococcosis in mice. It has been established that this relatively small, nonencapsulated yeast can exist in soil. In this form, the organism could be more readily disseminated by air currents, and it is more likely to be inhaled into the lungs than the larger encapsulated yeast. Nonencapsulated cells produce sufficient capsular material to inhibit phagocytosis by 50% when incubated for 5 to 10 hr with human lung tissue in vitro. The general assumption that the encapsulated cells are the etiological agent of naturally acquired cryptococcosis may have to be revised.
Effect of Animal Passage on Arthritogenic and Biological Properties of
Mycoplasma arthritidis
Authors: Golightly-Rowland L. , Cole B. C. , Ward J. R. , Wiley B. B.
Published: January 2020

Determinations of the ED
50
of cultures of
Mycoplasma arthritidis
disclosed the existence of great diversity in the arthritogenic properties of the various strains. In most cases, the ED
50
values were lowered after passaging in rats, and a more severe arthritis with a shorter period of onset was observed. Heavy suspensions of arthritogenic
M. arthritidis
did not appear to induce any toxic symptoms. Prior injections of endotoxin did not enhance the toxicity of
M. arthritidis
suspensions. The more arthritogenic strains grew more slowly in the basal medium and remained viable for longer periods of time than those with lower arthritogenic properties. All strains were identical on the basis of complement-fixation tests. Minor differences observed between strains during gel-diffusion studies could not be correlated with arthritogenic properties. Arthritogenic strains appeared to be less susceptible to the inhibiting action of rabbit antisera than were the nonarthritogenic strains.
Humoral factors affecting mouse peritoneal cell adherence reactions to Ascaris suum
Authors: Ziprin R , Jeska E L
Published: January 2020

The abilities of normal mouse peritoneal exudate cells and fluids to mediate in vitro cell adherence reactions to Ascaris suum juveniles were investigated. Exudates were induced by intraperitoneal injection of Sephadex G-25 or by infection with A. suum and changes in the peritoneal cell populations were determined. The presence of a heat-labile component, probably complement, and a heat-stable component, probably immunoglobulin, in the peritoneal exudate fluid were required for optimum in vitro cell adherence reactions. The in vitro cell adherence reactions were inhibited by ethylenediaminetetraacetic acid; the inhibition was overcome by the addition of calcium and magnesium ions.
Relationship between cell-bound dextransucrase and the agglutination of Streptococcus mutans
Authors: McCabe M M , Smith E E
Published: January 2020

Dextran-induced agglutination of Streptococcus mutans cells is independent of cell-bound dextransucrase activity. Toluene extraction or the presence of Hg2+ or Cu2+ markedly decreased or completely abolished cell-bound dextransucrase activity without adversely affecting dextran-induced cell agglutination. Cells treated by heating at 100 C until cell-bound dextransucrase was completely inactivated continued to agglutinate when induced by dextran-induced cell agglutination resulted from cell treatment with trypsin and several other enzymes, as well as from ethylenediaminetetraacetic acid treatment, without a corresponding loss of cell-bound dextransucrase activity. Cells possessed a greater avidity for branched dextrans of low molecular weight than for linear dextrans of the same weight, indicating that size alone does not determine the efficiency of dextran as an inducer of agglutination. Divalent metal ions were required for both sucrose- and dextran-induced agglutination of S. mutans K1-R cells. Although normal cells of strain 6715-49 did not appear to require divalent cations for agglutination, heat- and ethlyenediaminetetraacetic acid-treated cells specifically required Ca2+. The role of Ca2+ in cell agglutination may be either to activate the cell-surface dextran receptor or to form specific intercellular Ca2+ bridges.
Scanning electron microscopic study of virulent and avirulent colonies of Neisseria gonorrhoeae
Authors: Elmros T , Hörstedt P , Winblad B
Published: January 2020

A preparation procedure for scanning electron microscopy was developed by which gononcoccal colonies can be studied directly on the agar surface. After glutaraldehyde fixation directly in petri dishes, small agar pieces were cut out and dehydrated stepwise in increasing concentrations of ethanol. The blocks were thereafter transferred to a critical-point drying apparatus, via steps of increased gradients up to 100% amyl acetate. By this method five different gonococcal colony types could be distinguished analogous to light microscopic observations made by others. At higher magnifications an abundance of intercellular strands was found between the cells in virulent type 1 and 2 colonies, but not in the avirulent types 3 through 5. These strands seemed to anchor the cells to each other and to the agar surface. The presence of such structures probably explains the highly convex surface of virulent colonies and explains why colonies of avirulent strains exhibit a radial extension and a flat upper surface. The nature of these filamentous intercellular strands is discussed.
Cell-associated subacute sclerosing panencephalitis agent studied in organotypic central nervous system cultures: viral rescue attempts and morphology
Authors: Sheppard R D , Raine C S , Burnstein T , Bornstein M B , Feldman L A
Published: January 2020

Organotypic cultures of hamster cerebellum were exposed to the IP-3-Ca cell line , which contains a cell-associated subacute sclerosing panencephalitis agent. Central nervous system (CNS) cultures were examined by light and electron microscopy as well as standard virological techniques from 3 to 46 days postinfection. The results indicate that although viral nucleocapsid material was transferred to elements of the CNS, cell-free virus could not be detected by virological techniques and by electron microscopy, and budding viral particles were not observed. Attempts to recover cell-free virus from hamster CNS tissue exposed to IP-3-Ca cells were generally negative. However, 2% of the cultures yielded low levels of infectious virus. IP-3-Ca cells were able to transfer the cell-associated viral material to all cell types found in the CNS cultures and were capable of inducing polykaryocytes in the CNS cultures. The role of cell-associated virus-like agents in subacute sclerosing panencephalitis and other chronic CNS infections is discussed.
Carbon sources utilized by virulent Treponema pallidum
Authors: Nichols J C , Baseman J B
Published: January 2020

Carbon sources utilized by virulent Treponema pallidum organisms extracted from infected rabbit tissue have been investigated. Utilization of 14C-labeled compounds by T. pallidum was monitored by degradation of these compounds to 14CO2. Experiments have consistently shown that of 22 carbon sources examined, [14C]glucose and [14C]pyruvate are selectively degraded to 14CO2 under the experimental conditions employed. When [1-14C]pyruvate, [2-14C]pyruvate, and [3-14C]pyruvate are tested, virulent T. pallidum preferentially degrade and release the carboxyl group as 14CO2. End product analyses indicate that CO2 and acetate are the major products of pyruvate degradation by T. pallidum.
Stimulation of human lymphocytes by a vaccine strain of Francisella tularensis
Authors: Tärnvik A , Löfgren S
Published: January 2020

An immune response to Francisella tularensis was demonstrated in man by the lymphocyte stimulation test. Peripheral blood lymphocytes were obtained from 26 individuals vaccinated with a viable tularemia vaccine, from 29 unvaccinated individuals, and from two patients who had recently undergone tularemia. The lymphocytes were incubated in the presence of various dilutions of heat-killed bacteria of the vaccine strain. The bacteria induced a deoxyribonucleic acid synthesis in the lymphocytes from 18 of the vaccinated individuals and from the two patients which was higher than that in the lymphocytes from any of the unvaccinated individuals. The deoxyribonucleic acid synthesis was maximal after about 6 days of incubation irrespective of concentration of bacteria. Lymphocytes from vaccinated and unvaccinated individuals were stimulated by two unrelated agents, tuberculin purified protein derivative and pokeweed mitogen. Lymphocytes from the vaccinated individuals did not show a higher response to these agents than did those of the unvaccinated. This suggests that the lymphocyte response to the Francisella bacteria was not due to a nonspecific activation. The vaccine-induced lymphocyte stimulation did not correlate with serum antibodies agglutinating F. tularensis antigen.
Murine model for study of cell-mediated immunity: protection against death from fully virulent Francisella tularensis infection
Authors: Eigelsbach H T , Hunter D H , Janssen W A , Dangerfield H G , Rabinowitz S G
Published: January 2020

To assess cell-mediated immunity in terms of host protection, an experimental model was developed in which passively transferred spleen cells from immunized AKR/J mice enabled nonimmume syngeneic recipients to survive an otherwise fatal infection with fully virulent Francisella tularensis. Donor immunization was achieved by administering live attenuted tularemia vaccine and, subsequently, the virulent streptomycin-sensitive SCHU S4 strain of F. tularensis. At selected intervals after immunization, donor spleen cells were transferred to streptomycin-treated recipients challenged subcutaneously, intravenously, or intraperitoneally with 25 to 50 minimal lethal doses of virulent streptomycin-resistant F. tularensis SCHU S5. The protection afforded by immune spleen cells was maximal (essentially 100%) 12 days after the SCHU S4 secondary immunization.
Molecular construction of Clostridium botulinum type A toxins
Authors: Sugii S , Sakaguchi G
Published: January 2020

Two Clostridium botulinum type A toxic fractions, named large (L) and medium (M) toxins, were eluted from Sephadex G-200. Sucrose density gradient centrifugation resolved L toxin (2.5 X 10(8) to 3.0 X 10(8) mean lethal doses per mg of N) into two fractions, 19S and 16S. The same procedure performed at pH 8resolved it into three fractions; the heavier two were both nontoxic and hemagglutinin positive, and the lightest on (7S) was toxic. M toxin (12S) (4.5 X 10(8) to 5.0 X 10(8) mean lethal doses per mg of N) was homogeneous in electrophoresis and centrifugation at pH 6. The latter procedure performed at pH 8 dmonstrated that it dissociated into uniform 7S components. The nontoxic component of M toxin was free from hemagglutinin. M toxin alone was demonstrated in culture by sucrose density gradient centrifugation at pH 6. Dialysis of the culture supernatant resulted in partial formation of 16S toxin. Centrifugation of the crystalline toxin in 1 MNaCl demonstrated 16S toxin only. The toxic components of L, M, and crystalline toxins were antigenically identical. The nontoxic components of the crystalline and L toxins, consisting of two distinct antigens, were antigenically identical; that of M toxin was identical with one of these two antigens.
Suppressor T cells and host resistance to tye 111 pneumococcus after treatment with antilymphocyte serum
Authors: Barth R F , Singla O , Liu C
Published: January 2020

The antibody response to type III pneumococcal polysaccharide (SS-II) was significantly increased in mice treated with antilymphocyte serum (ALS). BALG/c mice given 0.25 ml of ALS on days -1, 0, and 1 relative to the days of immunization with 0.5 mug of SSS-II had a 20-fold increment (11,383 increased to 199,917) in the number of splenic plaque-forming cells enumerated on day 5 compared with untreated, immunized controls. This effect has been attributed to the elimination of subpopulation of thymus-derived lymphocytes (T cells) that has suppressor function. The present series of experiments relate the augmented antibody response to SSS-II in mice treated with ALS to increased host resistance after infection with Streptococcus pneumoniae, type III (Pn-II). The 50% lethal dose of Pn-III in niminnunized mice was 102 and the 100% lethal dose was 103 organisms. Mice immunized with 0.5 mug of SSS-III and challenged 5 days later with Pn-III were completely protected against a dose of up to 108 organisms. Mice treated with 0.25 ml of ALS on days -1, 0, and 1, immunized with SSS-III on day 0, and challenged with 2.5 X 10(9) Pn-III on day 5 had a mean survival time of greater than 100 h compared with 16 h for immunized non-serum-treated controls. Animals given a single injection of ALS before immunization showed no increase in resistance, whereas mice treated after immunization had significant prolongation of survival times. Untreated, immunized mice challenged with 5 X 10(9), 1 X 5 X 10(8) Pn-II survived 14 to 19 h, whereas ALS-treated animals had mean survival times of 48, 174, and 222 h, respectively. These findings suggest that immunoregulatory T cells may have a biologically significant effect in a narrow zone in which the normal host immune response is insufficient but still potentially capable of providing some additional degree of protection if suppressor cells are elimated.
Distribution of cholera organisms in experimental Vibrio cholerae infections: proposed mechanisms of pathogenesis and antibacterial immunity
Authors: Schrank G D , Verwey W F
Published: January 2020

This study was undertaken to determine the sequence of events in the microenvironment of the intestinal tract that culminate in the symptoms of cholera and to attempt to define more clearly the mechanisms involved in antibacterial immunity. The extent to which mucus occurs in the normal intestine of rabbits and the appearance of the intestinal villi in unfixed frozen sections was demonstrated. The villi and intervillous spaces were found to be normally covered by a layer of mucoid material that formed a mucous zone between the intestinal contents and the tips of the villi. The distribution of cholera organisms in normal and immunized animals was demonstrated by the staining of frozen-tissue sections with specific fluorescent antibody. Study of tissue sections from normal animals showed that the onset of fluid accumulation was concomitant with the establishment of large masses of organisms in the intervillous spaces and crypts of the intestine after the successful penetration of this mucous zone. Tissue sections from animals actively or passively immunized against a cell wall antigen of Vibrio cholerae showed clumping of vibrios in the lumen and restricted distribution in the lumen and luminal border of the mucous zone. Antibody was not lytic in vivo.
Microbial synergy in experimental intra-abdominal abscess
Authors: Onderdonk A B , Bartlett J G , Louie T , Sullivan-Seigler N , Gorbach S L
Published: January 2020

Intra-abdominal sepsis was studied in Wistar rats by using four microbial species: Escherichia coli, enterococci, Bacteroides fragilis, and Fusobacterium varium. These organisms were implanted into the peritoneal cavity singly and in all possible dual combinations. Results were evaluated by mortality rates and the incidence of intra-abdominal abscesses on autopsy following sacrifice after 7 days. Mortality was restricted to recipients of E. coli, thus implicating coliforms in the acute lethality associated with this experimental model. Intra-abdominal abscesses were produced in 61 of 95 (94%) animals that received the combination of an anaerobe and a facultative organism. Abscesses failed to form with any single strain or with E. coli plus enterococci, and they were detected in one 1 of 19 animals receiving B. fragilis plus F. varium. These results suggest that intra-abdominal abscess formation is related to synergy between anaerobes and facultative bacteria.
Inhibition of lipopolysaccharide-initiated activation of serum complement by polymyxin B
Authors: Morrison D C , Jacobs D M
Published: January 2020

Treatment of bacterial lipopolysaccharides (endotoxins) isolated from Salmonella minnesota R595 or purified lipid A with the antibiotic polymyxin B has been demonstrated to abrogate the ability of these molecules to activate serum complement. The inhibition is a function of the ratio of polymyxin B to lipopolysaccharide.
Properties of a mutant of Streptococcus mutans altered in glucosyltransferase activity
Authors: Kuramitsu H K
Published: January 2020

A mutant of Streptococcus mutans GS-5 has been isolated as a smooth colonial variant on mitis salivarius agar. This mutant, designated SNG-1, adheres to glass surfaces as well as the parental organism when grown in the presence of sucrose. However, in contrast to the parental organism, glucose-grown cultures of the mutant did not adhere to smooth surfaces when incubated with sucrose under nongrowing conditions. The inability of the mutant organism to adhere to glass surfaces under the latter condition was a result to markedly reduced levels of mutant cell-associated glucosyltransferase activity. In addition, the extracellular activity of the mutant was also severely depressed relative to the parental activity. The reduced levels of mutant enzyme activity appear to be a result of a mutation in a structural gene coding for glucosyltransferase activity since (i) mutant glucosyltransferase activity is much less resistant to heat inactivation compared to the parental enzymes and (ii) the migration patterns of the mutant and parental enzymes differ on polyacrylamide gels and after isoelectric focusing on polyacrylamide gels. However, the kinetic properties of the mutant enzymes are similar to those of the comparable parental activities in terms of pH and temperature optima and Km values for sucrose. The mutant enzyme responsible for soluble glucan synthesis has been purified approximately 300-fold. These results are discussed in terms of the mechanism of glucan synthesis by S. mutans.
Electron microscope study of experimental enteric adenovirus infection in mice
Authors: Takeuchi A , Hashimoto K
Published: January 2020

Using fluorescent antibody techniques (FA) and light microscopy (LM) and electron microscopy (EM), this paper describes the morphological features of the ileum in the DK1 mouse orally challenged with adenovirus K87. At the peak of infection, virus is easily identified by FA in the epithelium of the villi and crypts of the ileum. LM shows that fluorescent cells have large, bizarre, uniformly basophilic nuclei containing deoxyribonucleic acid, as indicated by histochemical tests. EM further identifies these nuclei as belonging to columnar, goblet, or Paneth cells, all epithelial cells facing the lumen with a microvillus border. The basophilic material in the nuclei consists of virus particles 75 nm in diameter arranged in crystalline arrays. When found in the cell cytoplasm, the virions do not form arrays but are scattered or form irregular aggregates, which may or may not be enclosed by single membranes. Infected columnar cells show mild cytopathic effects with no cell degeneration and necrosis, whereas the goblet and Paneth cells appear normal and maintain synthetic and secretory functions. All infected cells, however, share an abnormally accelerated extrusion rate, with columnar and goblet cells often being shed from the side rather than from the tip of the villi. The Paneth cells, which do not migrate out of the crypts, show a higher than normal rate of extrusion in the crypt lumen.
Reed Neurological Research Center, UCLA School of Medicine, Los Angeles, California
Authors: Stevens J G , Nakamura R M , Cook M L , Wilczynski S P
Published: January 2020

Various clinical, virological, immunological, and morphological aspects of velogenic Newcastle disease were defined in chickens inoculated by natural routes with the Missouri-(H) Len 1950 strain. The disease initially appeared as a severe pneumonitis from which most birds recovered. Several days later, many of these birds developed severe encephalitic signs, largely referable to inflammatory changes in the cerebellum. During the pneumonic stage, virus was easily isolated in relatively high titers from the brains of all chickens, and viral products were easily detected in Purkinje neurons. However, when the encephalitis developed, virus was isolated irregularly and in low titers from brains, and morphological evidence for the presence of viral products could not longer be obtained. The encephalitic disease is discussed in relation to encephalitic syndromes induced by other neurotrophic viruses.