scholarly journals STUDIES CONCERNING THE RELATIONSHIP BETWEEN PNEUMOCOCCI AND STREPTOCOCCI

1927 ◽  
Vol 45 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Hobart A. Reimann
Keyword(s):  
Streptococcus Viridans ◽  
Freezing And Thawing ◽  
Lytic Action ◽  
Immunological Reactions ◽  
The Relationship

Morgenroth and his collaborators grew pneumococci in a medium containing optochin and derived variant forms of bacteria therefrom which were considered to be streptococci of the viridans group. We have repeated these experiments and have also derived variant forms. These atypical races, however, we have found to be identical with the R form of pneumococci which have been obtained by various other methods. That these R cultures are still pneumococci and do not belong in the Streptococcus viridans group is supported by the following observations: 1. These strains are not bile-insoluble, but are more resistant to the lytic action of this agent than are type-specific pneumococci. 2. R strains behave like pneumococci and not like streptococci in the readiness with which cultures spontaneously autolyze and saline suspensions disintegrate during freezing and thawing. 3. Immunological reactions of the variant pneumococci derived by Morgenroth's method are identical with the immunological reactions of R forms of pneumococci derived by various other means. The observations of Morgenroth and his associates in regard to the transformation of Streptococcus hæmolyticus into Streptococcus viridans by treatment with rivanol could not be repeated in this laboratory. No explanation is at hand for our failure to produce the change. It is of course possible that none of the twenty-six strains tested had suitable tendencies to variation or that the technic or reagents employed varied from those of Morgenroth.

scholarly journals Water Loss during Contracture of Muscle

1962 ◽  
Vol 46 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Benjamin Kaminer
Keyword(s):  
Smooth Muscle ◽  
Water Loss ◽  
Significant Loss ◽  
Frog Muscle ◽  
Tetanic Stimulation ◽  
Force Of Contraction ◽  
Freezing And Thawing ◽  
Microscopic Studies ◽  
Relationship Of ◽  
The Relationship

The relationship of contracture and exudation of water in frozenthawed frog muscle was studied. With maximum shortening, there was a water loss of 35 per cent of the weight of muscle. By restricting the contraction, it was demonstrated that the amount of water loss was proportional to the degree of shortening, there being no significant loss with isometric contraction. Muscle already shortened by tetanic stimulation also exuded water on subsequent freezing and thawing. The force of contraction could be reduced by depleting the muscle of calcium and it was shown that the amount of water exuded was also proportional to the tensile ability of the muscle. In a smooth muscle (anterior byssus retractor of Mytilus) which did not contract vigorously only a little water exuded. Contracture produced by caffeine was similarly associated with a loss of water. Microscopic studies revealed a disruption of the sarcomeres of the frozen-thawed muscle which contracted; glycerol-extracted and calcium-depleted muscles, which did not contract on freeze-thawing, did not show such disruption. Freezing and thawing of actomyosin caused a reversible syneresis of the protein. It is concluded that the exudation of the water is not merely due to the freezing and thawing but is also dependent on the contractile events.

scholarly journals Classification of the Tatra Mountain lakes in terms of the duration of their ice cover (Poland and Slovakia)

2019 ◽  
Vol 79 (1) ◽  
Author(s):  
Bogdan Gadek ◽  
Mirosław Szumny ◽  
Bartłomiej Szypuła
Keyword(s):  
Climate Change ◽  
Ice Cover ◽  
Individual Characteristics ◽  
Freezing And Thawing ◽  
Digital Elevation ◽  
Mountain Environment ◽  
Elevation Model ◽  
The Impact ◽  
The Relationship

This paper presents the results of a classification of the Tatra lakes based on the duration of their ice cover, altitude, volume, and potential incoming solar radiation (PISR). It is embedded in the context of the impact of current climate change on the mountain environment. A digital elevation model, morphometric data, satellite imagery from the winter seasons of 2015-2017 and the Wrocław taxonomy method were used in the study. It was found that the order of freezing and thawing of the lakes investigated may change from year to year. The relationship between ice cover duration and altitude is clearly weakened by variations in lake volumes, with insolation having a noticeably lesser effect. Determining the duration of ice cover of the lakes over several seasons facilitates identifying the similarities and dissimilarities between them. Five groups of lakes displaying similar characteristics were identified as well as 2 groups of lakes with highly individual characteristics. Based on the data obtained, it can be concluded that the duration of ice cover on the Tatra lakes has been shortening noticeably over the last 100 years. Small high-altitude lakes seem to be most vulnerable to climate change.

scholarly journals Infective Endocarditis Caused by Oral Microorganisms and Entrance Door and Previous Dental Procedures: Does a Relationship Exists?

2020 ◽  
pp. 1-3
Author(s):  
Manuel Anguita Sánchez ◽  
Juan C. Castillo ◽  
Manuel Anguita Sánchez ◽  
Manuela Herrera ◽  
Martín Ruiz ◽  
...  
Keyword(s):  
Streptococcus Viridans ◽  
Oral Streptococci ◽  
Dental Floss ◽  
Therapeutic Implications ◽  
Dental Procedures ◽  
Entrance Door ◽  
History Of ◽  
Low Sensitivity ◽  
The Relationship ◽  
Oral Microorganisms

There are no recent studies that have evaluated the epidemiological relationship between dental manipulations the etiology of IE by these microorganisms, basically Streptococcus viridans. Our objective is to analyse the relationship between these variables and the possible therapeutic implications. For this, we have analysed a prospective single-center series of IE in patients not addicted to parenteral drugs collected and followed between 1987 and 2018. 403 cases of native and late prosthetic IE were diagnosed and followed up in our center. Of them, 91 were produced by oral streptococci (22.6%). The percentage of this microorganism has remained constant throughout the 30 years (24.8% of the cases from 1987-1997, 25% of those from 1998-2007 and 19.1% from 2008-2018. Although there was a history of dental manipulation in a greater proportion in cases of IE due to Streptococcus viridans (24% vs. 6.5%, p <0.001), in most cases due to Streptococcus viridans (76% of them) there was no previous dental manipulation. In these cases, the infection may be due to the usual daily manipulations of the mouth (brushing, dental floss) or periodontal disease. Given this low sensitivity, it cannot be ruled out that IE is caused by this microorganism in the absence of a history of visiting the dentist, with the implications for empirical antibiotic treatment that this entails

scholarly journals STUDIES ON THE MULTIPLICATION AND THE PROPERTIES OF THE LACTIC DEHYDROGENASE AGENT

1963 ◽  
Vol 117 (5) ◽  
pp. 735-747 ◽  
Author(s):  
Abner Louis Notkins ◽  
Stephen J. Shochat
Keyword(s):  
Enzyme Activity ◽  
Low Temperatures ◽  
Lactic Dehydrogenase ◽  
Supernatant Fluid ◽  
Freezing And Thawing ◽  
Plasma Enzyme ◽  
Ldh Activity ◽  
Virus Dose ◽  
The Relationship

The procedure used to determine the infective titer of the LDH agent, the reproducibility of this assay, and the relationship between virus dose and plasma enzyme activity were described. Multiplication of the LDH agent began within 6 hours after infection and reached 1010.8 ID50/ml of plasma within 24 hours. The titer rapidly decreased over the next 72 hours but viremia persisted for at least 16 months with titers as high as 105.2 ID50/ml. The appearance of the LDH agent in the circulation preceded the first noticeable rise in plasma LDH activity by close to 24 hours. After 10 months, when the plasma titer of the LDH agent had decreased nearly one millionfold, the plasma enzyme LDH had decreased by less than 50 per cent. The LDH agent is inactivated by ether but withstands lyophilization, and freezing and thawing. It is stable at low temperatures. Ultracentrifugation at 105,000 G for 2 hours leaves less than 0.1 per cent of the LDH agent in the supernatant fluid and filtration through gradocol membranes suggesst that the upper size of the LDH agent is about 55 mµ. Spread of the LDH agent from infected to uninfected mice kept in the same cage and transmission from mothers (infected prior to mating) to their offspring was relatively low.

scholarly journals IMMUNOLOGICAL REACTIONS BETWEEN DEXTRAN POLYSACCHARIDE AND SOME BACTERIAL ANTISERA

1932 ◽  
Vol 55 (3) ◽  
pp. 353-360 ◽  
Author(s):  
José Zozaya
Keyword(s):  
Active Group ◽  
Streptococcus Viridans ◽  
Bacterial Polysaccharide ◽  
Immunological Relationship ◽  
Immunological Reactions

Dextran, the synthetic polysaccharide produced by Leuconostoc mesenterioides from saccharose, reacts immunologically with antisera from pneumococci, some of the Sahnonella and some of the types of Streptococcus viridans (Bargen). This immunological relationship is independent of the specific antipolysaccharide antibodies of these sera, suggesting the existence of a distinct antibody produced by an active group of the specific bacterial polysaccharide, which is similar or identical to the active group of the dextran polysaccharide.

scholarly journals The Research on Tests for Detecting Strength of Shallow Asphalt Pavement under Ice Frozen

2012 ◽  
Vol 5 ◽  
pp. 293-298
Author(s):  
Mao Cai Zhao ◽  
Shi Xian Gao ◽  
Da Wei Shi ◽  
Qi Shu Huang
Keyword(s):  
Compression Test ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Guizhou Province ◽  
Uniaxial Compression Test ◽  
Penetration Test ◽  
Freezing And Thawing ◽  
Tensile Splitting Strength ◽  
The Relationship ◽  
Diametral Compression Test

The thesis utilizes the Penetrating Strength Detector of Shallow Pavement to conduct impacting penetration experiment, uniaxial compression test and diametral compression test to asphalt mixture of different void ratios and cycles of freezing and thawing, and then we’ve obtained the relationship between average penetration depth and compressive strength as well as tensile splitting strength of mixture, moreover, the initial reference standard of the Penetrating Strength Detector of Shallow Pavement is established. Afterwards, the thesis conducts impacting penetration test to the asphalt pavement cores from Chongzun freeway in Guizhou Province suffering from ice frozen damage. The effectiveness of the Penetrating Strength Detector of Shallow Pavement has been proved.

Canaline carbamoyltransferase in human liver as part of a metabolic cycle in which guanidino compounds are formed.

1977 ◽  
Vol 23 (6) ◽  
pp. 960-966 ◽  
Author(s):  
S Natelson ◽  
A Koller ◽  
H Y Tseng ◽  
R F Dods
Keyword(s):  
Butyric Acid ◽  
Human Urine ◽  
Liver Tissue ◽  
Human Liver ◽  
Carbamoyl Phosphate ◽  
Human Liver Tissue ◽  
Lytic Action ◽  
Guanidino Compounds ◽  
The Relationship ◽  
Metabolic Cycle

Abstract This and previous papers examine the reasons for the relationship between the concentrations of guanidino-succinate and guanidinoacetate in human urine. With the demonstration here that extracts of human liver-tissue can mediate ureidohomoserine formation from canaline [(2-amino-4-aminooxy)-butyric acid] and carbamoyl phosphate, all steps in a cycle proposed for the production of guanidinoacetate and guanidinosuccinate have been documented. This includes synthesis of canavaninosuccinate from aspartate and ureidohomoserine, reductive cleavage of canavaninosuccinate to form guanidinosuccinate and homoserine, or, alternatively, lytic action on canavaninosuccinate to form fumarate and canavanine, and transamidination to glycine to form guanidinoacetate, regenerating the canaline. We propose that canaline originates from aspartate, but the precise mechanism by which canaline is formed needs to be elucidated.

The uptake of ( 35 S) sulphate by mucopolysaccharides of granulation tissue

1955 ◽  
Vol 144 (914) ◽  
pp. 100-115 ◽  
Keyword(s):  
Granulation Tissue ◽  
Chondroitin Sulphate ◽  
Enzymatic Reaction ◽  
Freezing And Thawing ◽  
Sulphated Polysaccharides ◽  
Sulphate Uptake ◽  
S Uptake ◽  
The Relationship

In order to gain some insight into the formation and fate of the sulphated polysaccharides of granulation tissue, the ( 35 S) sulphate uptake of regenerating tendons of guinea-pigs was determined in vivo . Hexosamine and hydroxyproline contents were estimated at various stages of healing. The maximum 35 S uptake occurred after the seventh day and was maintained for at least 8 more days, returning to low values on the 23rd day after operation. The relationship between sulphate uptake, hexosamine and hydroxyproline contents was determined and discussed. In scurvy, the uptake of 35 S was lower than in controls, while hexosamine values were unchanged. This was presumed to indicate that though the total amount of polysaccharide in scorbutic granulation tissue was undiminished, it was not sulphated in the normal way. A polysaccharide component, which was highly radioactive and had a mobility of approximately the same order as chondroitin sulphate, was separated from normal granulation tissue by extraction and ionophoresis on paper. It was thus shown that sulphation of a mucopolysaccharide was responsible for the uptake of 35 S. The mechanism of ( 35 S) sulphate uptake was studied in vitro by incubating slices of granulation tissue in a medium containing radioactive sulphate. Disruption of cells by homogenization or freezing-and-thawing greatly reduced the incorporation of sulphate. Little or no uptake of 35 S occurred in boiled tissue, in the cold, or in the absence of oxygen. 2:4-Dinitrophenol, azide, cyanide and certain sulphydryl-binding substances were found to inhibit the reaction. Salicylate caused an inhibition, while cortisone had no such effect. Scorbutic granulation tissue showed a decreased fixation of sulphate. It was concluded that sulphate uptake by granulation tissue was dependent on an enzymatic reaction, possibly involving oxidative phosphorylation.

Test Research on Thermal Conductivities of Silty Clay in Freezing and Thawing Based on Thermal Current Meter Method (TCMM)

2013 ◽  
Vol 341-342 ◽  
pp. 1472-1476
Author(s):  
Qing Song Guo ◽  
Xin Li ◽  
Min Li
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurement ◽  
Dry Density ◽  
Silty Clay ◽  
Freezing And Thawing ◽  
Disturbed Soil ◽  
The Relationship ◽  
Test Process ◽  
Water Contents ◽  
Thermal Conductivities

Silty clay’s disturbed soil samples of were measured to ascertain the correlations between thermal conductivity and dry density or water content in the freezing and thawing conditions and provide a certain reference for soil’s thermal conductivity measurement of underground project in seasonal frozen area in future. The relationship between another variable and thermal conductivity was inquired into through fixing one variable in the test process. Through the test data analysis, the conclusion can be drawn as followed. Keeping dry density unchanged, silty clay’s thermal conductivities in freezing and thawing increase with water contents. When dry densities are different, the growth trends of thermal conductivities are slightly different. In the same moisture content, the relation between dry density and thermal conductivity appears as positive correlation.

Finite Element Analysis for Concrete Damage under Freeze-Thaw Action

2009 ◽  
Vol 417-418 ◽  
pp. 133-136 ◽  
Author(s):  
Ji Ze Mao ◽  
Hong Ye Wang ◽  
Zhi Yuan Zhang ◽  
Zong Min Liu
Keyword(s):  
Finite Element ◽  
Dynamic Modulus ◽  
Damage Mechanics ◽  
Concrete Strength ◽  
Failure Surface ◽  
Surface Model ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Finite Element Software ◽  
The Relationship

Freeze-thaw damage is one of the most representative damages in concrete durability. Commonly, freezing and thawing tests are conducted to investigate the freeze-thaw resistance of concrete, and the loss of dynamic modulus of concrete is regarded as the failure criterion. However, the research on the evolution of concrete strength during the damage process is still not enough when subjected to freezing and thawing. In this study, the concrete freeze-thaw deterioration was considered as isotropic elastic damage, and relative variation functions of dynamic modulus and Poisson’s ratio with freeze-thaw cycles were set up. Based on damage mechanics, the Ottosen failure surface model with four parameters was established to indicate the relationship between the concrete freeze-thaw failure surface and freeze-thaw cycles. Then the four-parameter failure surface model was set into ADINA finite element software program for secondary development to investigate the strength properties of concrete component under freeze-thaw action. The relationship between load and deflection of concrete was analyzed and simulated after 0, 25 and 50 freeze-thaw cycles. The simulated and experimental results are basically identical, which demonstrates that this finite element simulation is a feasible way to analyze and evaluate the performance of concrete structures in cold regions.

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