THE MULTIPLICATION OF THE VIRUS OF YELLOW FEVER IN A?DES AEGYPTI

Aëdes aegypti have been shown to be capable of multiplying the Asibi strain of yellow fever virus in their bodies. Following the ingestion of infected blood, the content of virus falls for several days, reaching a minimum during the 1st week. It then increases rapidly until quantities of virus greater than those previously encountered can be demonstrated. The actual final amount of virus demonstrable, however, is subject to variations of which we know little.     

A STUDY OF THE SPIROCH?TICIDAL ACTION OF THE SERUM OF PATIENTS TREATED WITH SALVARSAN

1. The serum of rabbits treated intravenously with neosalvarsan, and of syphilitic patients treated intravenously with salvarsan or neosalvarsan, has a definite spirochæticidal action upon Spirochœta duttoni. 2. Although this spirochæticidal action is exerted in vitro, it can be demonstrated only after the treated spirochætæ are injected into susceptible animals. 3. A curative action of the serum of neosalvarsan-treated rabbits is exercised on mice infected with Spirochœta duttoni. 4. The spirochæticidal action of the serum of salvarsan-treated rabbits and patients is markedly increased by heating at 56° C. for thirty minutes. 5. The increased spirochæticidal action produced by heating is due in part to the destruction of some inhibitory substance contained in normal serum and in part to a direct effect of the heat upon the serum and salvarsan mixture. 6. Cerebrospinal fluid does not contain the inhibitory substance present in normal unheated serum.     

THE INHIBITORY EFFECT OF ACRIDINE ON THE SPOROGONY OF A COCCIDIUM (EIMERIA STIED?)

The development or ripening of the oocyst of the coccidium of the rabbit is prevented by acridine hydrochloride provided that the cysts are exposed to the action of the chemical before development has started. After sporoblasts are formed acridine does not prevent further development. Many other substances, some of them known to be active against certain protozoan parasites, have no influence on the ripening of the oocysts of the coccidium.     

THE R?LE OF THE THYROID IN THE REGULATION OF THE BLOOD CHOLESTEROL OF RABBITS

1. The blood cholesterol of rabbits on a normal diet without added cholesterol is increased only slightly (19 per cent) by thyroidectomy. 2. In rabbits with a hypercholesterolemia due to long continued cholesterol feeding, thyroidectomy causes a marked rise (137 per cent) in the blood cholesterol. This rise is usually maintained. 3. When long continued cholesterol feeding has failed to cause a rise in the blood cholesterol of rabbits, thyroidectomy abolishes this resistance and a hypercholesterolemia is promptly produced. 4. A single injection of thyroxin causes a significant drop in the blood cholesterol of rabbits with hypercholesterolemia. This reaction is not influenced by thyroidectomy. 5. Potassium iodide causes an increase in the blood cholesterol of rabbits with hypercholesterolemia. This reaction is not influenced by thyroidectomy in contrast to the effect of KI in preventing a rise in blood cholesterol when given concurrently from the beginning of cholesterol feeding, an effect which is abolished by thyroidectomy. It is suggested that two different mechanisms are involved. 6. A single injection of insulin produces a fall in the blood cholesterol of rabbits with hypercholesterolemia. If anything, thyroidectomy increases the magnitude of this effect.     

THE EFFECTS OF ANTICIPATION ON THE MECHANICS OF THE KNEE DURING SINGLE‐LEG CUTTING TASKS: A SYSTEMATIC REVIEW

Background

ACL injuries are common in sports, which has resulted in the development of risk screening and injury prevention programs to target modifiable neuromuscular risk factors. Previous studies which have analyzed single‐leg cutting tasks have reported that the anticipation status of the task (pre‐planned vs. unanticipated) has a significant effect on the mechanics of the knee.

Hypothesis/Purpose

The purpose of this systematic review is to assess the effect of anticipation on the mechanics of the knee in the sagittal, frontal, and transverse planes during tasks which athletes frequently perform during competition.

Study Design

Systematic Review

Methods

The following databases were searched using relevant key words and search limits: Pub Med, SPORTDiscus, CINAHL, and Web of Science. A modified version of the Downs and Black checklist was used to assess the methodological quality of the articles by two independent reviewers.

Results

284 articles were identified during the initial database search. After a screening process, 34 articles underwent further review. Of these articles, 13 met the criteria for inclusion in this systematic review.

Conclusions

It appears that tasks which do not allow a subject to pre‐plan their movement strategy promote knee mechanics which may increase an athlete''s risk of injury.

Clinical Relevance

Clinicians involved in the development and implementation of ACL injury risk screening and prevention programs may want to consider incorporating tasks which do not allow time for pre‐planning. These unanticipated tasks may more closely mimic the demands of the sports environment and may promote mechanics which increase the risk of injury.

Level of Evidence

Level 1b     

THE R?LE OF THE MUCOID POLYSACCHARIDE (HYALURONIC ACID) IN THE VIRULENCE OF GROUP A HEMOLYTIC STREPTOCOCCI

1. A quantitative turbidimetric method for the estimation of hyaluronidase activity, based on the ability of the enzyme to decrease the capacity of the polysaccharide to precipitate acidified protein has been developed. Two units of hyaluronidase, by this method, are equivalent to one viscosity-reducing unit. 2. Hyaluronidase added to a phagocytic system containing defibrinated human blood, immune or non-immune, greatly increases the rate of phagocytosis of group A streptococci. Phagocytosis of Type I pneumococci is not affected by hyaluronidase under the same conditions. 3. The bactericidal activity of non-immune blood against group A streptococci is increased by hyaluronidase; the activity of immune blood is, however, somewhat inhibited by the enzyme. Killing of pneumococci is not affected by the presence of the enzyme. 4. Mice can be protected against group A streptococcal infection by frequent treatment with 200 turbidity-reducing units of hyaluronidase; the protective action of the enzyme is removed by heating at 60°C. for 1 hour. Mice infected with Type I pneumococcus and treated with hyaluronidase die somewhat sooner than the untreated controls.     

THE R?LE OF THE THEBESIAN VESSELS IN THE CIRCULATION OF THE HEART

In summary, evidence has been presented to show a direct connection other than through the capillaries between the coronary arteries and the chambers of the heart. This connection was shown by perfusion, injections and serial sections to be through the Thebesian veins. Communications between the larger coronary veins and the Thebesian veins were also demonstrated by the same methods. Serial sections through Thebesian veins have shown capillaries draining directly into them. Under certain conditions it has been shown that as much as 90 per cent of the arterial flow may escape via the Thebesian vessels. Lastly, in the event of gradual closure of the orifices of the coronary arteries, the Thebesian vessels can supply the heart muscle with sufficient blood to enable it to maintain an efficient circulation.     

THE MODE OF SPREAD OF A FRIEDL?NDER BACILLUS-LIKE RESPIRATORY INFECTION OF MICE

A spontaneous respiratory disease of mice incited by Friedländer like bacilli has been described. The bacilli inducing the disease, while morphologically and culturally indistinguishable from the usual varieties of Friedländer bacilli, are antigenically distinct from the common type strains known. The bacilli grow better in cultures at 23°C. than at 37°C. The disease in mice displayed an incubation period of about 48 hours. About 50 per cent of an exposed population succumbed to septicemic and acute hemorrhagic, pneumonic processes. Among the exposed animals were some individuals which remained apparently well and carried the pathogenic bacilli in their nasal passages. The several manifestations of the spontaneous disease were reproduced by instilling small numbers of the cultured bacilli into the nasal passages. 48 hours after inoculation, certain mice had already succumbed; the deaths continued to occur, so that by the end of the 2nd week, 70–80 per cent of the animals had died. Among the survivors certain carriers of the bacilli in the nasal passages occurred; a few appeared entirely refractory to the infection. The succumbing mice showed at autopsy and by culture septicemia and diffuse pneumonic inflammation. No fluctuation in virulence could be detected in bacilli derived from mice while the disease was spreading spontaneously at the periods of epidemic rise, interepidemic interval, or postepidemic quiescence. Moreover, the bacilli cultured from the nares of apparently healthy carriers were equally pathogenic with those taken from the blood and lungs of animals succumbing quickly. No rough colony variants were cultured at any phase of the spontaneous disease, although they were readily obtainable by artificial culture. The variant strains proved stable and of low virulence. This Friedländer bacilli infection in mice takes several clinical courses, depending on variations in host reaction and not depending on bacterial variation. The particular type of infection manifested is determined by the degree of resisting power displayed by the infected animals at the moment that the infection occurred and progressed.     

CHANGES IN THE SHAPE AND SIZE OF BACTERIUM COLI AND BACILLUS MEGATHERIUM UNDER THE INFLUENCE OF BACTERIOPHAGE—A MOTION PHOTOMICROGRAPHIC ANALYSIS OF THE MECHANISM OF LYSIS

This paper contains the records of a motion photomicrographic investigation of the lysis of Bact. coli and B. megatherium by bacteriophage. The bacteria mixed with bacteriophage were grown on moist nutrient agar in small culture chambers on the stage of a microscope in an incubator maintained at 37°C. The apparatus used permitted continuous inspection of the preparations. Photographs were made at the rates of 2 and 30 per minute and at the rate of 8 per second during the terminal stage of lysis of Bact. coli. The accurately timed films were studied by rapid projection and by the projection of single frames. Measurements of dimensions of cells, calculations of volumes, information on generations, generation times and duration spans are presented in the tables. Similar information on normal cultures grown and photographed in the same way is furnished for comparison. Groups of serial photographs are reproduced in the plates to illustrate the special features observed. These observations seem to us to warrant the following conclusions: 1. Enlargement or swelling of the cells of Bact. coli usually, but not always, precedes lysis. Some of the enlargement is an expression of increase of cell substance and is not altogether due to imbibition of water. Cells of early generations of Bact. coli enlarge to greater absolute and relative proportions than cells of later generations. Enlargement does not occur before lysis in B. megatherium. 2. The terminal stage of lysis of Bact. coli is explosive, occupying ½ to ⅞ second. The terminal stage of lysis of B. megatherium is a slow disintegrative process, extending over 2–10 minutes. 3. Bacteriophage inhibits fission of some cells, but does not stop the reproduction of other cells in contact with it. The genealogical records of six generations of cells of Bact. coli and of two generations of cells of B. megatherium indicate that bacteriophage may be transmitted through parents to the offspring which ultimately undergo lysis. 4. Bacteriophage spreads by contact through a group of cells and also along paths determined by genetical relationships. 5. A large amount of cellular debris remains after the lysis of the cells in both of these species of bacteria. This residue of material is in the form of irregularly shaped masses and granules. This material is not in solution at the time of lysis and appears not to be digested or hydrolized. 6. Theories of the mechanism of lysis are discussed. It is suggested that reduction of surface tension of the cells may be an important factor in the mechanism of lysis.     

THE FACTORIAL STRUCTURE OF THE ARABIC VERSION OF THE REVISED COLLETT–LESTER FEAR OF DEATH SCALE

A sample of 209 volunteer Kuwaiti undergraduates responded to an Arabic version of the Revised Collett–Lester Fear of Death Scale with 4 subscales: Death of Self, Dying of Self, Death of Others, and Dying of Others. Reliabilities of the 4 subscales and of the grand total score ranged from 0.75 to 0.92, which is considered adequate. A 4-factor solution was congruent with the allocation of items to 2 subscales (i.e. Dying of Self and Death of Others), whereas the theorized factor structure of the other 2 subscales were only partially supported by empirical analyses. The intercorrelations between the 4 total subscale scores yielded a general factor of death and dying, denoting good factorial validity of the scale.     

THE RELIABILITY OF THE VAIL SPORT TEST? AS A MEASURE OF PHYSICAL PERFORMANCE FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Purpose/Background:

The decision to return an athlete to sports following anterior cruciate ligament reconstruction can be controversial. The purposes of this study are 1) to describe a functional test (Vail Sport Test™) that includes the evaluation of muscle strength, endurance, power, and movement quality in those patients attempting to return to sports following ACL reconstruction and 2) to assess the reliability of the Vail Sport Test™.

Methods:

A prospective cohort study design. A total of 30 (12 F, 18 M) subjects (18.1±5.3 yrs) volunteered for the study. All subjects were post-operative ACL reconstruction (5.2±1.9 months) and were in the process of returning to sports. Each subject completed the Vail Sport Test™ and was videotaped from the anterior and lateral view. The videotape was then viewed and graded at two different points in time (48 hours apart) by three licensed physical therapists. Intraclass correlations (ICCs) were calculated to determine intra- and inter-rater reliability.

Results:

Intra-rater reliability was excellent with a range of .95 to 1.0. Reliability values between graders were .97 (ICC₂,k) and 1.55 (SEM).

Conclusions:

The results of this study suggest that the Vail Sport Test™ has excellent reliability when the same graders scored the test using video on repeated occasions. In addition, the test was reliable between different graders.

Level of Evidence:

Level 2b     

THE EFFECT OF OXIDATION OF FILTRATES OF A CHICKEN SARCOMA (CHICKEN TUMOR I—ROUS)

1. The rapid autoinactivation at 37° of candle filtrates of the Rous Foul Sarcoma I is due in large part to oxidation. 2. Such oxidation may be prevented by a dilution of 1-2000 cysteine hydrochloride brought to pH 7.4 with NaOH. 3. The variability of infectiousness of candle filtrates is due in part at least to oxidative changes which take place during their preparation; and more active extracts may be obtained by preventing these by means of cysteine. 4. For elaborate experiments it is possible to preserve filtrates in the ice box with cysteine and vaseline until test inoculations have established their infectivity.     

THE RóLE OF STREPTOCOCCI IN EXPERIMENTAL POLIOMYELITIS OF THE MONKEY

It is the opinion of Bull, that the streptococci recovered from poliomyelitic tissues, while having no etiological or pathological relationship to the virus of poliomyelitis, occur as secondary invaders in the disease. Smillie and Amoss indicated that the bacteria may be agonal invaders. The results of the experiments reported in this paper point to another source of the streptococci. They occur as contaminants which are introduced into the cultures during the process of grinding tissues. The source of the streptococcus may therefore be the air of the place in which the cultures are made. We have come to this conclusion because first, the tissues of which cultures yielded streptococci were derived from a number of monkeys with experimental poliomyelitis still in a vigorous state. Secondly, when the tissues were ground bacteria were noted much more frequently in their cultures than in those in which fragments of the same brains were used. Thirdly, microorganisms occurred more often in cultures made in the routine laboratory than in a special room where asepsis was carried to the extreme of a major surgical operation on man. Fourthly, streptococci were obtained from the air of the places where cultures were made. Finally, there is no correlation between the cultures of two portions of the same brain. The streptococci occurred in some cultures in pure growth and in others admixed with other ordinary species of bacteria. The latter were often found, in turn, in pure culture and what applies to streptococci, as mentioned in the preceding paragraph, applies equally to the staphylococci, diphtheroids, spore-bearing rods, and other miscellaneous, familiar microorganisms. We could not determine that there exists any etiological relation of the streptococci to poliomyelitis. The fermentation reactions of the microorganisms obtained from the air, from non-poliomyelitic and poliomyelitic monkey brains indicate that bacteria from any of these sources are markedly different. So also with the serological reactions of agglutination and precipitation. Furthermore no agglutination was observed when the serum of monkeys convalescent from experimental poliomyelitis was mixed with any of the streptococci recovered or those received directly or indirectly from Rosenow. Moreover, the intracerebral injection with cultures, irrespective of their source, induced in rabbits a purulent type of meningoencephalitis, often associated with streptococcic septicemia. This result is at marked variance with any known effects of the true filtrable virus of poliomyelitis in man and in the monkey.     

MANAGING BEREAVEMENT IN THE CLASSROOM: A CONSPIRACY OF SILENCE?

The ways in which teachers in British schools manage bereaved children are underreported. This article reports the impact of students' bereavement and their subsequent management in primary and secondary school classrooms in Southeast London. Thirteen school staff working in inner-city schools took part in in-depth interviews that focused on the impact of bereaved children on the school and how teachers responded to these children. All respondents had previously had contact with a local child bereavement service that aims to provide support, advice, and consultancy to children, their parents, and teachers. Interviews were audiotaped, transcribed verbatim, and analyzed using ATLAS-ti. Three main themes were identified from analysis of interview data. Firstly, British society, culture, local communities, and the family were significant influences in these teachers' involvement with bereaved students. Secondly, school staff managed bereaved students through contact with other adults and using practical classroom measures such as "time out" cards and contact books. Lastly, teachers felt they had to be strong, even when they were distressed.Surprise was expressed at the mature reaction of secondary school students to deaths of others. The article recommends that future research needs to concentrate on finding the most effective way of supporting routinely bereaved children, their families, and teachers.     

THE R?LE OF THE RETICULO-ENDOTHELIAL SYSTEM IN IMMUNITY : I. THE R?LE OF THE RETICULO-ENDOTHELIAL SYSTEM IN THE PRODUCTION OF DIPHTHERIA ANTITOXIN.

1. Following massive doses of India ink injected intravenously into guinea pigs before a subcutaneous injection of diphtheria toxin-antitoxin mixture, no antitoxin was found in the blood serum for 3 weeks, as indicated by intracutaneous tests, whereas an appreciable amount could be detected in non-blocked, immunized control animals. 2. During the 4th week following immunization, the titer of the serum of blocked animals equaled that of non-blocked controls within the limits of the intracutaneous test dose. 3. The smaller doses of India ink used in these experiments, given before immunization, had no stimulating effect on the production of diphtheria antitoxin but, on the contrary, also inhibited the appearance of this antibody, although to a less extent.