bluuebunny/crossref_metadata_2025 huggingface dataset:
A unique subtype of ramified microglia associated with synapses in the rat hippocampus
Authors: Ohgomori Tomohiro , Iinuma Kyoko , Yamada Jun , Jinno Shozo
Published: June 2021

To date, a number of studies have reported the heterogeneity of activated microglia. However, there is increasing evidence suggests that ramified, so‐called resting, microglia may also be heterogeneous, and they may play diverse roles in normal brain homeostasis. Here, we found that both 5D4 keratan sulfate epitope‐positive (5D4+) and 5D4‐negative (5D4‒) microglia coexisted in the hippocampus of normal rats, while all microglia were negative for the 5D4 epitope in the hippocampus of normal mice. We thus aimed to determine the potential heterogeneity of microglia related to the 5D4 epitope in the normal rat hippocampus. The optical disector analysis showed that the densities of 5D4+ microglia were higher in the stratum oriens of the CA3 region than in other layers and regions. Although both 5D4+ and 5D4‒ microglia exhibited a ramified morphology, the three‐dimensional reconstruction analysis showed that the node numbers, end numbers, and complexity of processes were higher in 5D4+ than in 5D4‒ microglia. The linear discriminant analysis showed that 5D4+ and 5D4‒ microglia can be classified into distinct morphometric subtypes. The ratios of contact between synaptic boutons and microglial processes were higher in 5D4+ than in 5D4‒ microglia. The gene expressions of pro‐inflammatory cytokine interleukin‐1β and purinergic receptor P2Y12 (P2Y12R) were higher in 5D4+ than in 5D4‒ microglia. Together, these results indicate that at least two different subtypes of ramified microglia coexist in the normal rat hippocampus and also suggest that 5D4+ microglia may represent a unique subtype associated with synapses.
Evaluation of the combined glucose‐insulin and intravenous glucose tolerance tests for insulin dysregulation diagnosis in donkeys
Authors: Mendoza Francisco Javier , Mejia‐Moreira Sebastian , Buchanan Ben R. , Toribio Ramiro E. , Perez‐Ecija Alejandro
Published: June 2021

Background

Insulin dysregulation (ID) and donkey metabolic syndrome (DMS) are common in this species. Contrary to horses, diagnostic guidelines compiling insulin cut‐offs values and dynamic testing interpretations have not been reported for this species.

Objectives

To evaluate resting serum insulin concentrations, the combined glucose‐insulin test (CGIT) and the glucose intravenous tolerance test (IVGTT) for the diagnosis of DMS with ID suspicion.

Study design

Diagnostic test comparison.

Methods

Six of 80 mix‐breed adult donkeys fulfilled the inclusion criteria for DMS based on history or clinical evidence of recurrent laminitis, body condition >6 and neck score >2 or baseline insulin and leptin concentrations >20 µIU/mL and >12 ng/mL respectively. CGIT and IVGTT were performed in all donkeys within a week and interpreted following guidelines reported for equine metabolic syndrome (EMS). Insulin and glucose curves were analysed, proxies calculated and correlations and multivariate analysis assessed.

Results

Following EMS guidelines, CGIT classified 2 (using glucose‐positive phase duration) or 3 (using insulin concentration) and IVGTT classified 5 donkeys as ID. ID donkeys showed a lower glucose/insulin ratio, QUICKI and RISQI, and a higher insulin/glucose ratio, MIRG and HOMA‐B%.

Main limitations

Comparison of these tests with additional dynamic testing including a larger number of ID donkeys is necessary.

Conclusions

This is the first study evaluating dynamic tests to assess ID/DMS in DMS‐suspected donkeys. IVGTT detected more ID donkeys than CGIT. EMS recommendations could also be used for DMS diagnosis, although a baseline insulin cut‐off value is needed.
LD‐transpeptidases: the great unknown among the peptidoglycan cross‐linkers
Authors: Aliashkevich Alena , Cava Felipe
Published: June 2021

The peptidoglycan (PG) cell wall is an essential polymer for the shape and viability of bacteria. Its protective role is in great part provided by its mesh‐like character. Therefore, PG‐cross‐linking enzymes like the penicillin‐binding proteins (PBPs) are among the best targets for antibiotics. However, while PBPs have been in the spotlight for more than 50 years, another class of PG‐cross‐linking enzymes called LD‐transpeptidases (LDTs) seemed to contribute less to PG synthesis and, thus, has kept an aura of mystery. In the last years, a number of studies have associated LDTs with cell wall adaptation to stress including β‐lactam antibiotics, outer membrane stability, and toxin delivery, which has shed light onto the biological meaning of these proteins. Furthermore, as some species display a great abundance of LD‐cross‐links in their cell wall, it has been hypothesized that LDTs could also be the main synthetic PG‐transpeptidases in some bacteria. In this review, we introduce these enzymes and their role in PG biosynthesis and we highlight the most recent advances in understanding their biological role in diverse species.
Antioxidant and anti‐inflammatory activities of ethyl acetate extracts of chub mackerel (Scomber colias): a thorough seasonal evaluation
Authors: Cardoso Carlos , Matos Joana , Gomes‐Bispo Ana , Afonso Cláudia , Motta Carla , Castanheira Isabel , Prates José A. M. , Bandarra Narcisa M.
Published: June 2021

The seasonal variation of key bioactivities in ethyl acetate extracts of chub mackerel (Scomber colias), an underutilised fish species, was evaluated through a complete monthly sampling. The phenolic content had a seasonal variation, ranging from 39 ± 5 mg GAE/100 g ww (February) to 340 ± 6 mg GAE/100 g ww (October). Ferric reducing antioxidant power (FRAP) increased from 1.3 ± 0.4 μmol Fe2+ Eq/g ww (January) to 10.3 ± 0.1 μmol Fe2+ Eq/g ww (September). ABTS had no antioxidant activity between June and December, being the highest value in February, 64.3 ± 6.3 μmol Trolox Eq/100 g ww. For phenolic content and FRAP, there was a strong seasonality, which was similar to that of the lipid content. Therefore, correlations were high, being R2 0.95 for lipid vs. phenolic contents. Anti‐inflammatory activity did not show large changes throughout most part of the year, remaining high in the 70–80% of COX‐2 inhibition. This finding and the seasonality of the antioxidant properties warrant further research.
High Performance Index as a tool to identify the best combination of pearled fractions and durum wheat genotypes for semolina and pasta colour improvement
Authors: Troccoli Antonio , De Leonardis Anna Maria , Platani Cristiano , Borrelli Grazia Maria
Published: June 2021

Debranning was applied to six durum wheat genotypes to identify specific fractions rich in carotenoids and lower in enzymatic activities useful for improving pasta colour. Six sequential debranning steps, each of 30 s, were applied. β‐carotene, lutein, α‐tocopherol and ash content and hydroperoxidation and bleaching activities of lipoxygenase were determined in all pearled fractions. A wide variability among the genotypes regarding the level of all components has been found. Most of the parameters were higher in the pearled fraction at 30 s than wholemeal. Compared to the latter fraction, a significant decreasing trend for both lipoxygenase activities and α‐tocopherol and ash content was subsequently observed, while β‐carotene decreased more slightly. Lutein content remained quite stable in all subsequent pearled fractions. The pearled fraction of the Ofanto obtained at 90 s of debranning was identified as the best genotype/pearled fraction combination through our High Performance Index tool.
An exploration of the levels of clinical autonomy of advanced nurse practitioners: A narrative literature review
Authors: Lockwood Emily B , Lehwaldt Daniela , Sweeney Mary Rose , Matthews Anne
Published: June 2021

Aims and Objectives

The aims of the review are to synthesise current evidence about advanced nurse practitioner clinical autonomy and consider how this may inform clinical practice and research.

Background

Clinical autonomy is one of the cornerstones of advanced nursing practice globally, yet there is limited synthesis of clinical autonomy in the literature.

Design

This is a narrative literature review.

Data sources

The databases Cumulative Index to Nursing and Allied Health Literature, EBSCO host, Cochrane Library, CINAHL and MEDLINE were searched for publications between 2005 and 2020 inclusive.

Review methods

A systematic approach was used to analyse the literature reviewed. Two reviewers undertook quality appraisal.

Results

Nineteen articles were selected. Four major themes emerged: (1) ‘ANP Stepping Up’—moving into and accepting advanced nursing practice roles and clinical responsibilities; (2) ‘ANP Living It’—ANPs' ability to act independently including an understanding of task mastery and self‐determination; (3) ‘ANP Bounce‐back ability’—depicted in challenges that threaten their ability to practice clinically autonomously; (4) ‘ANP Setting in Motion’—indirect care activities and service‐level improvements.

Conclusion

A clearer understanding of advanced nurse practitioner clinical autonomy could help develop more in‐depth knowledge. Research of advanced nurse practitioners' clinical autonomy would improve full utilisation in clinical practice.
Nucleating role of P2O5 in nepheline‐based transparent glass‐ceramics
Authors: Li Jizhong , Wang Mingzhong , Lu Ping
Published: June 2021

The nepheline‐based transparent glass‐ceramics are promising candidates for cover glass applications in electronic displays owing to their superior mechanical properties (than glasses) and ability to be chemically strengthened. However, our poor understanding about the kinetic and thermodynamic drivers controlling their crystallization processes usually results in their opacification and development of large internal stresses. The present work focuses on the development of nepheline‐based nanocrystalline transparent glass‐ceramic designed in the Na2O–Al2O3–SiO2 ternary system nucleated with P2O5. The temporal evolution of the phosphate and nepheline nanocrystal formation has been followed using X‐ray diffraction, scanning/transmission electron microscopy, and energy‐dispersive spectroscopy. The incorporation of P2O5 in the glass structure leads to the phase separation resulting in the crystallization of nanocrystalline Na3PO4 as an intermediate phase; thus, acting as a nucleating site for volume crystallization of nepheline. The optimization of nucleation and growth profile in the designed composition results in the formation of a transparent glass‐ceramic with high optical transmittance (91.5 ± 0.1%).
DYRK1A phosphorylates MEF2D and decreases its transcriptional activity
Authors: Wang Pin , Zhao Juan , Sun Xiulian
Published: June 2021

Myocyte enhancer factor 2D (MEF2D) is predominantly expressed in the nucleus and associated with cell growth, differentiation, survival and apoptosis. Previous studies verified that phosphorylation at different amino acids determined MEF2's transcriptional activity which was essential in regulating downstream target genes expression. What regulates phosphorylation of MEF2D and affects its function has not been fully elucidated. Here, we uncovered that dual‐specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A), a kinase critical in Down's syndrome pathogenesis, directly bound to and phosphorylated MEF2D at Ser251 in vitro. Phosphorylation of MEF2D by DYRK1A significantly increased MEF2D protein level but attenuated its transcriptional activity, which resulted in decreased transcriptions of MEF2D target genes. Phosphorylation mutated Ser251A MEF2D exhibited enhanced transcriptional activity compared with wild type MEF2D. MEF2D and DYRK1A were observed co‐localized in HEK293 and U87MG cells. Moreover, DYRK1A‐mediated MEF2D phosphorylation in vitro might influence its nuclear export upon subcellular fractionation, which partially explained the reduction of MEF2D transcriptional activity by DYRK1A. Our results indicated that DYRK1A might be a regulator of MEF2D transcriptional activity and indirectly get involved in regulation of MEF2D target genes.
Association of short sleep with risk of periodontal disease: A meta‐analysis and Mendelian randomization study
Authors: Zhou Feixiang , Liu Zongyan , Guo Yicong , Xu Huilan
Published: June 2021

Aim

The aim of this meta‐analysis and Mendelian randomization (MR) study was to assess the association between short sleep and periodontal disease, including tooth loss and periodontitis.

Materials and Methods

The meta‐analysis of relevant studies was conducted to assess the association between short sleep and periodontal disease. MR analyses were conducted with the inverse‐variance‐weighted (IVW) method, weighted median method, MR‐Egger method, and MR‐Robust Adjusted Profile Score (RAPS) method to assess the causal effect of short sleep on tooth loss and periodontitis.

Results

Seven cross‐sectional studies involving 40,196 individuals were included in the meta‐analysis. The association between short sleep and periodontal disease was not statistically significant (odds ratios (OR) =1.13, 95% confidence interval (CI): 0.99, 1.28;p = 0.076). In the MR analysis, we did not observe statistically significant causal associations of genetically determined short sleep with tooth loss (β: −0.056; 95% CI: −0.181 to 0.068;p = 0.376) and periodontitis (β: −0.112; 95% CI: −0.340 to 0.117;p = 0.339).

Conclusions

Short sleep is not associated with the risk of periodontal disease according to current evidence. Future studies need to pay attention to the measurement of sleep duration, the choice of statistical models, and other domains of sleep health.
Ectomycorrhizas and tipping points in forest ecosystems
Authors: Suz Laura M. , Bidartondo Martin I. , van der Linde Sietse , Kuyper Thomas W.
Published: June 2021

The resilience of forests is compromised by human‐induced environmental influences pushing them towards tipping points and resulting in major shifts in ecosystem state that might be difficult to reverse, are difficult to predict and manage, and can have vast ecological, economic and social consequences. The literature on tipping points has grown rapidly, but almost exclusively based on aquatic and aboveground systems. So far little effort has been made to make links to soil systems, where change is not as drastically apparent, timescales may differ and recovery may be slower. Predicting belowground ecosystem state transitions and recovery, and their impacts on aboveground systems, remains a major scientific, practical and policy challenge. Recently observed major changes in aboveground tree condition across European forests are probably causally linked to ectomycorrhizal (EM) fungal changes belowground. Based on recent breakthroughs in data collection and analysis, we apply tipping point theory to forests, including their belowground component, focusing on EM fungi; link environmental thresholds for EM fungi with nutrient imbalances in forest trees; explore the role of phenotypic plasticity in EM fungal adaptation to, and recovery from, environmental change; and propose major positive feedback mechanisms to understand, address and predict forest ecosystem tipping points.
Pleiotrophin attenuates the senescence of dental pulp stem cells
Authors: Zhang Lili , Xia Dengsheng , Wang Chao , Gao Feifei , Hu Lei , Li Juan , Jin Luyuan
Published: June 2021

Objectives

Pleiotrophin (PTN), a secreted extracellular matrix‐associated protein, plays an important role in regulating the osteo/dentinogenic differentiation potential of dental pulp stem cells (DPSCs). Our previous study has demonstrated that PTN expression in young DPSCs was is 10‐fold higher than that in aged DPSCs. However, the role of PTN on the in maintaining the stemness of senescent DPSCs remains unclear. The present study aimed to investigate the effect of PTN on senescent DPSCs in vitro.

Materials and Methods

Dental pulp stem cells were isolated from human third molars. PTN was knocked down using short hairpin RNAs to study the role of PTN on the senescence of DPSCs. DPSCs with aging performance were obtained by a replicative senescence cell model was obtained by the long‐term culture of DPSCs to the 15th passage in vitro (P15). We then investigated the effect of PTN on senescent DPSCs (P15 DPSCs). Real‐time RT‐PCR, western blotting, alizarin red staining, quantitative calcium analysis, SA‐β‐Gal staining, CFSE, and cell‐counting kit‐8 (CCK8) assays were used to study cellular senescence and function.

Results

The depletion of PTN increased the ratio of SA‐β‐gal‐positive cells, upregulated the expression of p16, and down‐regulated the expression of TERT and p‐p38. Furthermore, 50 pg/ml of PTN recombinant protein rescued these changes the altered ratio of SA‐β‐gal‐positive cells, decreased the expression of p16, enhanced TERT and p‐p38 expression, as well as telomere activity, caused by PTN depletion and long‐term culture. The15th passage cells displayed typical aging characteristic, including high ratio of SA‐β‐gal‐positive cells, increased aging‐related gene expression, decreased proliferation rate, high level of Cyclin D expression, and impaired osteo/dentinogenic differentiation potential. However, 50 pg/ml of PTN recombinant protein could partially reverse these alteration rescue these changes.

Conclusions

The present study demonstrated that PTN could protect DPSCs from senescence by improving the proliferation and osteo/dentinogenic differentiation ability, probably through the p38 MAPK pathway.
Spanish Anticausative Inherent Reciprocals and Syntactic Reciprocals with Se*
Authors: Quintana Hernández Lucía
Published: June 2021

Within the debate about the heterogeneity of unaccusative structures, the aim of this paper is to distinguish two types of Spanish marked anticausative inherent reciprocals (AIRs) from other syntactic reciprocals (SRs) withse. Several diagnostics show that AIRs such asmezclarse‘get mixed’ are symmetric, unaccusative, telic, and show causative alternations, while SRs are transitive and vary in their aspectual properties and do not show causative alternations. Theen/durante‘in/for’ adverbials test reveals that there are two types of AIRs: achievements such ascasarse‘get married’, and degree achievements such asmezclarse‘get mixed’. Although the clitic is an agreement marker in these reciprocal constructions, it is an expletive voice head withcasarse, a causative head withmezclarse, and an anaphor merged in the internal argument position in SRs. Differences between AIRs and SRs depend on semantic properties associated to their respective event structures.
Successive minima and asymptotic slopes in Arakelov geometry
Authors: Ballaÿ François
Published: June 2021

Let$X$be a normal and geometrically integral projective variety over a global field$K$and let$\bar {D}$be an adelic${\mathbb {R}}$-Cartier divisor on$X$. We prove a conjecture of Chen, showing that the essential minimum$\zeta _{\mathrm {ess}}(\bar {D})$of$\bar {D}$equals its asymptotic maximal slope under mild positivity assumptions. As an application, we see that$\zeta _{\mathrm {ess}}(\bar {D})$can be read on the Okounkov body of the underlying divisor$D$via the Boucksom–Chen concave transform. This gives a new interpretation of Zhang's inequalities on successive minima and a criterion for equality generalizing to arbitrary projective varieties a result of Burgos Gil, Philippon and Sombra concerning toric metrized divisors on toric varieties. When applied to a projective space$X = {\mathbb {P}}_K^{d}$, our main result has several applications to the study of successive minima of hermitian vector spaces. We obtain an absolute transference theorem with a linear upper bound, answering a question raised by Gaudron. We also give new comparisons between successive slopes and absolute minima, extending results of Gaudron and Rémond.
Vibration Modes of Stators of Induction Motors
Authors: Erdelyi E. , Horvay G.
Published: June 2021

The increased emphasis placed on the design of “noiseless” machinery has led to the requirements of better evaluation of the magnetic attractive forces developed between rotor and stator of induction motors, better evaluation of stator response to such forces, and better evaluation of the sound waves radiated by the vibrating stator frame. This paper treats the crucial phase of the problem, determining the vibration characteristics of two concentric shells (stator core inside the stator frame) coupled by nonrigid ribs. The vibration theory of such coupled structures is developed and the theoretical results are compared with the experimental measurements obtained for a 30-hp, 3-phase, induction motor. The agreement is within 7 per cent. Parts 1 and 3 of the problem, determination of the airgap force waves and of the sound radiated, are discussed in separate papers.
The Effect of a Circular Hole on the Pure Twist of an Infinite Strip
Authors: Tamate Osamu
Published: June 2021

In a previous paper by the author (1), a theoretical solution for an infinite strip with a circular hole under plain bending is given by the method of successive approximation. This method demands laborious calculations. However, it seems that the labor can be diminished by employing the method of perturbation. In this paper, the effect of a circular hole in an infinite strip under the state of pure twist is investigated with the help of the perturbation method. The maximum deflections on the rim of the hole and the maximum stress couples in the strip are calculated and plotted versus hole-diameter strip-width ratio and Poisson’s ratio of the plate material. Here the strip is considered subjected to the limitation of the Poisson-Kirchhoff theory of bending of thin plates.
A New Approach to the Theory of Thin, Slightly Cambered Profiles
Authors: Weinig F. S.
Published: June 2021

If real and imaginary parts of a function of a complex variable are interpreted as velocity potential and stream function, then real and imaginary parts of the kth derivatives are the (k–1) st derivatives of the velocity components in the direction of the real and negative imaginary axis. For slightly cambered profiles that deviate little from the real axis and have the shape of a polynomial of nth order, the imaginary part of the nth derivative of the complex potential is constant in first-order approximation. It is easy to establish such functions of the complex variable in the case of single as well as cascade profiles. Integration then yields the intended results. While there is no continuing need for such a method for single profiles, it is needed for cascades of profiles.
Effect of Adverse Pressure Gradients on Turbulent Boundary Layers in Axisymmetric Conduits
Authors: Robertson J. M. , Holl J. W.
Published: June 2021

The development of the three-dimensional boundary layer in a diffuser with several discharge arrangements has been studied for air flow, in continuation of the work of Uram (1). The flow conditions in a diffuser when followed by a straight pipe, an additional length of the diffuser, or a jet, are compared. Extension of the method of analysis developed by Ross for two-dimensional layers is presented. In some cases the use of three-dimensionally defined parameters leads to different results. Ross’s (2) unique outer-flow parameter is found to be no longer satisfactory. Other outer parameters are presented as possible substitutes.
A Statistical Appraisal of the Prot Method for Determination of Fatigue Endurance Limit
Authors: Hijab W. A.
Published: June 2021

A statistical analysis of the precision of the estimate of endurance limit as determined by the Prot method is carried out. This analysis shows that the Prot method cannot achieve a great saving in the number of specimens required, for its statistical efficiency is found to be even less than that of its other two competitors, the probit and staircase methods. This fact, coupled with serious objections to its assumptions, renders its usefulness highly questionable. A secondary result of the analysis is that the optimum efficiency of the Prot method is achieved when only two rates of increase of stress, as widely separated as possible, are used. A derivation of a general formula, of which the Prot method is a particular case and which makes explicit all assumptions necessary for the valid derivation of the Prot method, is also given.
Forced Vibration of Systems With Nonlinear, Nonsymmetrical Characteristics
Authors: Mahalingam S.
Published: June 2021

A one-term approximate solution is given for the amplitudes of steady forced vibration of a single-degree-of-freedom system with a nonlinear (nonsymmetrical) spring characteristic. The method is similar to that of Martienssen (1), but the construction uses a modified curve (or “frequency function”) in place of the actual spring characteristic, the curve being so chosen that it gives the correct frequency for free vibrations. The method is extended to deal with a nonlinear vibration absorber fitted to a linear system.
Displacements in a Wide Curved Bar Subjected to Pure Elastic-Plastic Bending
Authors: Shaffer Bernard W. , House Raymond N.
Published: June 2021

Equations have been obtained for the displacements and strains within a wide curved bar made of a perfectly plastic, incompressible material subjected to a pure bending moment which is sufficiently large to cause elastic-plastic stresses. It is found that whenever the applied load is within 95 per cent of the fully plastic bending moment, displacements and strains in the elastic-plastic problem are of the order of magnitude of the corresponding elastic case. It is also found that when the bending moment reaches approximately 65 per cent of the fully plastic bending moment, the change in material thickness reaches a maximum. It decreases to zero when the bar becomes completely plastic.
The Creep of Thick Tubes Under Internal Pressure
Authors: Weir C. D.
Published: June 2021

Using the usually accepted assumption that the strain rate of a material undergoing creep is given by the product of the stress deviator and a function of the shear-strain energy, and assuming constant density, equations are derived for the creep stresses in a thick-walled tube under internal pressure for a generalized form of the shear strain-energy function. It is shown that these reduce to previously published equations on the substitution of a power law stress-strain rate equation. The nonisothermal case is considered also and creep-stress equations are obtained in a similarly generalized form.
Symmetrical Buckling of a Series of Uniformly Loaded Parallel Struts Supported by Spot Connections to a Long Thin Plate
Authors: Cutcliffe J. L. , Heaps H. S.
Published: June 2021

The deflection in buckling of a long panel consisting of parallel stiffeners across a rectangular plate is found when equal buckling loads are applied to the ends of each stiffener. The critical load for buckling is found as a function of the elastic properties of the plate and the stiffeners for various spacings of stiffeners, and the number of spot connections to the plate.
Effect of Elastic Racks on Vibration Mounting of Equipment
Authors: Di Taranto R. A.
Published: June 2021

The over-all fundamental natural frequency of a uniform beam supported at each end by equal springs is determined in terms of the first-mode bending natural frequency of the beam and the natural frequency of the lumped mass beam on the two springs. This is qualitatively applied to the case of electronic equipment on elastic racks supported on vibration mounts.
Knee Extensor Mechanism Strength and Its Relationship to Patellofemoral Kinematics in Individuals With Arthrofibrosis Within 6 Months After Anterior Cruciate Ligament Reconstruction
Authors: Zhang Ling , Wang Shao-bai , Fan Shuai , Ye Jiling , Cai Bin
Published: June 2021

Context: Performance in strength and assessment of patellar tracking is important for patients with arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. Objective: The study was to examine the difference of patellofemoral kinematics between the affected and the contralateral limb and to evaluate the relationship between knee extensor strength and patellofemoral kinematics in patients with arthrofibrosis after ACL reconstruction. Design: Cohort study (diagnosis); level of evidence, 3. Setting: Laboratory. Patients: A prospective cohort of 20 patients with arthrofibrosis after ACL reconstruction was recruited. Interventions: A total of 20 patients who underwent arthroscopic reconstruction of the double-bundle ACL with a hamstring tendon autograft received standardized patellofemoral kinematics testing and knee extensor strength testing within 6 months after primary ACL reconstruction. Computed tomography and dual fluoroscopic imaging were used to evaluate in vivo patellofemoral kinematics of affected and contralateral knees during a lunge task. Knee extensor mechanism strength was measured using a handheld dynamometer. Main Outcome Measures: A limb symmetry index of knee strength and patellar mobility was calculated and satisfactory performance defined as ≥90%. Results: There was a statistically significant decrease in the range of patellar inferior shift (P = .020; d = 0.81), flexion (P = .026; d = 0.95), lateral tilt (P = .001; d = 1.04), and lateral rotation (P < .001; d = 0.89) in the affected knee compared with the contralateral knee from 15° to 75° of knee flexion. There was a strong positive linear correlation between knee extensor strength and patellar inferior shift (r = .747; P = .008). A knee extensor strength limb symmetry index <90% was 89% sensitive and 9% specific for limited patellar inferior shift. Conclusions: Patients with arthrofibrosis after ACL reconstruction presented decreased patellar mobility in the arthrofibrotic knee compared with the contralateral knee. The strong correlation between knee extensor strength and patellar inferior shift of the arthrofibrotic knee demonstrates the importance of knee extensor strength in the diagnosis and treatment of patients with knee arthrofibrosis. The knee extensor mechanism strength has high sensitivity but low specificity in identifying a decrease in patellar inferior shift in patients with arthrofibrosis after ACL reconstruction.
Simplified Method for Efficient Intravascular Inoculation of Chicken Embryos
Authors: Kelling C. L. , Schipper I. A.
Published: June 2021

The simple syringe-stabilizer unit described in this note provides a means for rapid intravascular inoculation of embryonated chicken eggs with minimal embryonic death from vascular trauma.
Comparison of bacteriological methods for the isolation of group of B Streptococcus from vaginal cultures
Authors: Baker C J , Goroff D K , Alpert S L , Hayes C , McCormack W M
Published: June 2021

Three bacteriological techniques for the isolation of group B streptococci in vaginal cultures were compared. A selective broth medium (SBM) containing gentamicin and nalidixic acid was more sensitive for the detection of vaginal isolates (28/76, 36.8%) from 76 women enrolled in a venereal disease clinic than was an identical selective plate medium (SPM) (17/76, 25%). Similarly, SBM allowed identification of positive cultures from college women (82/459, 17.9%) significantly more often than direct inoculation of swabs onto nonselective blood agar medium (43/460, 9.4%; chi2 = 42.2, P = less than 0.001). Failure to isolate group B streptococci detected in SBM occurred in 32.1% cultures by SPM and 49.4% of cultures by nonselective agar medium. Multiple serotypes were detected in a single vaginal culture from approximately 5% of the patients studied. These data support the routine use of SBM for the most accurate identification of women vaginally colonized with group B Streptococcus.
Identification of streptococcal groups A,B,C, and G by slide co-agglutination of antibody-sensitized protein A-containing staphylococci
Authors: Hahn G , Nyberg I
Published: June 2021

A total of 98.7% of streptococci, groups A,B,C, and G, isolated from various sources was correctly identified by the co-agglutination technique. The active components in this technique are protein A-containing staphylococci coated with antibodies specific for group A,B,C, and G streptococci. A suspension of streptococci belonging to one of these four groups co-agglutinates with the antibody-sensitized staphylococci specific for this group. The technique is extremely rapid and simple and requires no special equipment. It should therefore be a valuable alternative to other techniques used in the grouping of streptococci and is shown here to be as reliable as the Lancefield technique.
Yersinia enterocolitica isolates from humans in California, 1968-1975
Authors: Bissett M L
Published: June 2021

This paper reports on the serological and biochemical characteristics of 24 human isolates of Yersinia enterocolitica submitted to the California Department of Health from 1968 through 1975. Nine different serotypes were represented. The majority of strains were serotype O:8 (six strains) and serotype O:5 (five strains). Sources of the isolates included feces (12 cases), blood (3), sputum or throat (3), bile or bowel drainage (2), wounds (2), breast abscess (1), and skin abscess (1). Clinical histories indicated a number of different syndromes. Underlying medical conditions existed in 13 cases. Results of selected biochemical tests and antimicrobial susceptibility tests on the strains indicated grouping compatible with the O serotypes of the organisms.
Convenient System for Multiple Screening of Microbial Carbohydrate Metabolism
Authors: Young Elaine , Udey Lanny R.
Published: June 2021

A rapid technique for inoculating carbohydrate oxidation and fermentation media is described. This method employs 24-well tissue culture trays and a multi-inoculator. Other applications are discussed.
Comparison of the sensitivity of two methods for isolation of Mycoplasma pneumoniae
Authors: Craven R B , Wenzel R P , Calhoun A M , Hendley J O , Hamory B H , Gwaltney J M
Published: June 2021

Throat swab specimens from 1,494 Marine Corps recruits were inoculated into vials containing diphasic (broth/agar) mycoplasma medium and also onto PPLO agar plates, which were subsequently overlayed with sheep erythrocytes in saline agar. Strains of Mycoplasma pneumoniae were isolated from 89 (6%) of the specimens by one or both of the methods. Eight-one of the 89 (91%) positive specimens were cultured with diphasic medium, whereas only 42 (47%) were cultured with the overlay method (x2 = 7.44, P less than 0.01). The diphasic system for isolation of M. pneumoniae should be the method of choice in clinical and research application.
Absence of wide-zone, alpha-hemolytic streptococci in children with pharyngitis
Authors: Saitz E W , Stratigos S
Published: June 2021

Wide-zone, alpha-hemolytic streptococci are potential sources of false-positive throat cultures since they can be misinterpreted as beta-hemolytic streptococci. However, quantitative information regarding their occurrence in sick children was not available. Throat swabs from 312 children with pharyngitis were processed conventionally and also with pour-plate methods and examination of the positive cultures under magnification. One-third of all cultures were positive for beta-hemolytic streptococci. There were no significant differences in the number of positive cultures among or between the different methods. Wide-zone, alpha-streptococci were found in none of the cultures. Therefore, they are unlikely to be a common cause of false-positive cultures in children with pharyngitis.
Quantitative and bacteriological studies of urine specimens from canine and feline urinary tract infections
Authors: Wooley R E , Blue J L
Published: June 2021

The most prevalent microorganisms isolated from urine specimens of dogs (385) and cats (132) with clinical signs of urinary tract infections were Escherichia coli, Proteus spp., and Staphylococcus aureus. The results of quantitative urine-culturing methods showed 48.6% of the canine and 12.1% of the feline specimens had more than 10(5) organisms per ml of urine. The bacteria isolated appear to have a greater resistance to antibacterial agents than previously reported.
Immunoglobulin specificity for the fluorescent treponemal antibody-absorption test conjugate
Authors: Hunter E F , Maddison S E , Larsen S A , Felker M B , Feeley J C
Published: June 2021

Quantitative indirect immunofluorescence tests have demonstrated the predominance of immunoglobulin G antibody in most stages of syphilis. A class-specific anti-human immunoglobulin G conjugate is recommended to replace the present fluorescent treponemal antibody-absorption test conjugate. This would allow further definition and standardization of the fluorescent treponemal antibody-absorption test.
Solid-Phase Radioimmunossay for Rapid Detection and Identification of Western Equine Encephalomyelitis Virus
Authors: Levitt Neil H. , Miller Helen V. , Eddy Gerald A.
Published: June 2021

A solid-phase radioimmunoassay technique was adapted for the rapid detection and identification of western equine encephalomyelitis virus in clinical specimens.
Deoxyribonuclease: detection with a three-hour test
Authors: Greenwood J R , Pickett M J
Published: June 2021

A three-hour test has been developed to determine deoxyribonuclease activity of Enterobacteriaceae and staphylococci. The test is inexpensive and easy to perform. The rapid deoxyribonuclease test and the conventional method showed complete agreement with the strains tested.
Selective medium for distinguishing micrococci from staphylococci in the clinical laboratory
Authors: Curry J C , Borovian G E
Published: June 2021

A nitrofuran-containing medium, FTO agar, supported the growth of Micrococcus and prevented the growth of Staphylococcus. Its potential as a differential medium is considered worthy of clinical trial.
Prevalence of hepatitis B surface antigen and antibody in white and black patients with diabetes mellitus
Authors: Kew M C , MacKay M E , Mindel A , Joffe B I , Kusman B , MacNab G M , Seftel H C
Published: June 2021

The prevalence of hepatitis B surface antigen (HBSAg) and antibody (anti-HBS) was determined in 531 white and 519 black diabetic outpatients and in appropriate white and black control populations. There was no difference between the prevalence of either HBSAg or anti-HBS in either the white or black diabetics and that in the white and black controls. These findings make it unlikely that the vast majority of patients with diabetes mellitus have either an increased susceptibility to infection by the hepatitis B virus or an impaired ability to clear the virus once they are infected.
Quantitation of Friend spleen focus-forming virus by a nine-day 59Fe assay
Authors: Menna J H , Hankins W D , Krantz S B
Published: June 2021

A previously described 3-day 59Fe assay for quantitation of Friend spleen focus-forming virus has been modified to produce a 200-fold more sensitive 9-day 59Fe assay. A characterization of this assay is reported here. Male BALB/c mice received intravenous injections of appropriately diluted Friend polycythemia virus (FVP); control mice received virus diluent. All mice were allowed food and water ad libitum for 6 days, and on day 6 after virus injection were fasted by removal of food but not water. On day 3 of the fast (the 9th day after virus injection) each mouse received an intraperitoneal injection of 1 muCi of 59Fe. Six hours later the mice were sacrificed and the splenic radioactivity was determined. The percent splenic incorporation of 59Fe was directly related to the logarithm of spleen focus-forming units (SFFU) of FVP injected in a range of approximately 25 to 1,000 SFFU. Using a standard FVP preparation in a dose range of 25 to 1,000 SFFU, it was possible to determine the SFFU titers of unknown samples by extrapolation of the percent splenic 59Fe incorporation to the logarithm of SFFU. SFFU titers obtained by the 9-day 59Fe assay were similar to those obtained by the enumerative-response assay. Advantages of the 9-day 59Fe assay over the enumerative-response assay include a 50-fold greater virus dose range, an easier and a more objective counting procedure, and a reduced coefficient of variation.
Nucleocytoplasmic transport of macromolecules
Authors: Corbett A H , Silver P A
Published: June 2021

Nucleocytoplasmic transport is a complex process that consists of the movement of numerous macromolecules back and forth across the nuclear envelope. All macromolecules that move in and out of the nucleus do so via nuclear pore complexes that form large proteinaceous channels in the nuclear envelope. In addition to nuclear pores, nuclear transport of macromolecules requires a number of soluble factors that are found both in the cytoplasm and in the nucleus. A combination of biochemical, genetic, and cell biological approaches have been used to identify and characterize the various components of the nuclear transport machinery. Recent studies have shown that both import to and export from the nucleus are mediated by signals found within the transport substrates. Several studies have demonstrated that these signals are recognized by soluble factors that target these substrates to the nuclear pore. Once substrates have been directed to the pore, most transport events depend on a cycle of GTP hydrolysis mediated by the small Ras-like GTPase, Ran, as well as other proteins that regulate the guanine nucleotide-bound state of Ran. Many of the essential factors have been identified, and the challenge that remains is to determine the exact mechanism by which transport occurs. This review attempts to present an integrated view of our current understanding of nuclear transport while highlighting the contributions that have been made through studies with genetic organisms such as the budding yeast, Saccharomyces cerevisiae.
Stable DNA replication: interplay between DNA replication, homologous recombination, and transcription
Authors: Kogoma T
Published: June 2021

Chromosome replication in Escherichia coli is normally initiated at oriC, the origin of chromosome replication. E. coli cells possess at least three additional initiation systems for chromosome replication that are normally repressed but can be activated under certain specific conditions. These are termed the stable DNA replication systems. Inducible stable DNA replication (iSDR), which is activated by SOS induction, is proposed to be initiated from a D-loop, an early intermediate in homologous recombination. Thus, iSDR is a form of recombination-dependent DNA replication (RDR). Analysis of iSDR and RDR has led to the proposal that homologous recombination and double-strand break repair involve extensive semiconservative DNA replication. RDR is proposed to play crucial roles in homologous recombination, double-strand break repair, restoration of collapsed replication forks, and adaptive mutation. Constitutive stable DNA replication (cSDR) is activated in mhA mutants deficient in RNase HI or in recG mutants deficient in RecG helicase. cSDR is proposed to be initiated from an R-loop that can be formed by the invasion of duplex DNA by an RNA transcript, which most probably is catalyzed by RecA protein. The third form of SDR is nSDR, which can be transiently activated in wild-type cells when rapidly growing cells enter the stationary phase. This article describes the characteristics of these alternative DNA replication forms and reviews evidence that has led to the formulation of the proposed models for SDR initiation mechanisms. The possible interplay between DNA replication, homologous recombination, DNA repair, and transcription is explored.
Microbial physiology and ecology of slow growth
Authors: Koch A L
Published: June 2021

The uptake capabilities of the cell have evolved to permit growth at very low external nutrient concentrations. How are these capabilities controlled when the substrate concentrations are not extremely low and the uptake systems could import substrate much more rapidly than the metabolic capabilities of the cell might be able to handle? To answer this question, earlier theories for the kinetics of uptake through the cell envelope and steady-state systems of metabolic enzymes are discussed and a computer simulation is presented. The problems to the cell of fluctuating levels of nutrient and too much substrate during continuous culture are discussed. Too much substrate can lead to oligotrophy, substrate-accelerated death, entry into the viable but not culturable state, and lactose killing. The relationship between uptake and growth is considered. Finally, too little substrate may lead to catastrophic attempts at mounting molecular syntheses that cannot be completed.
Signal transduction and transcriptional and posttranscriptional control of iron-regulated genes in bacteria
Authors: Crosa J H
Published: June 2021

Iron is an essential element for nearly all living cells. Thus, the ability of bacteria to utilize iron is a crucial survival mechanism independent of the ecological niche in which the microorganism lives, because iron is scarce both in potential biological hosts, where it is bound by high-affinity iron-binding proteins, and in the environment, where it is present as part of insoluble complex hydroxides. Therefore, pathogens attempting to establish an infection and environmental microorganisms must all be able to utilize the otherwise unavailable iron. One of the strategies to perform this task is the possession of siderophore-mediated iron uptake systems that are capable of scavenging the hoarded iron. This metal is, however, a double-edged sword for the cell because it can catalyze the production of deadly free hydroxyl radicals, which are harmful to the cells. It is therefore imperative for the cell to control the concentration of iron at levels that permit key metabolic steps to occur without becoming a messenger of cell death. Early work identified a repressor, Fur, which as a complex with iron repressed the expression of most iron uptake systems as well as other iron-regulated genes when the iron concentration reached a certain level. However, later work demonstrated that this regulation by Fur was not the only answer under low-iron conditions, there was a need for activation of iron uptake genes as well as siderophore biosynthetic genes. Furthermore, it was also realized that in some instances the actual ferric iron-siderophore complex induced the transcription of the cognate receptor and transport genes. It became evident that control of the expression of iron-regulated genes was more complex than originally envisioned. In this review, I analyze the processes of signal transduction, transcriptional control, and posttranscriptional control of iron-regulated genes as reported for the ferric dicitrate system in Escherichia coli; the pyochelin, pyoverdin, and enterobactin systems in Pseudomonas species; the irgB system in Vibrio cholerae; and the plasmid-mediated anguibactin system in Vibrio anguillarum. I hope that by using these diverse paradigms, I will be able to convey a unifying picture of these mechanism and their importance in the maintenance and prosperity of bacteria within their ecological niches.