J D VAN RAMSHORST’s research while affiliated with National Institute for Public Health and the Environment and other places

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Publications (17)


International collaborative studies on potency assays of diphtheria and tetanus toxoids
  • Article

February 1972

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15 Reads

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17 Citations

Bulletin of the World Health Organization

J D Van Ramshorst

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T K Sundaresan

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A S Outschoorn

Collaborative studies showed that relative potency assays for a particular type of diphtheria toxoid (adsorbed) and for tetanus toxoid (plain and adsorbed) gave very similar results, whether the assays were carried out by toxin challenge or by antitoxin titration after immunization of experimental animals with graded doses of toxoid. The same numerical results were obtained with a scoring system as with a system based on survivals only. Although skin tests were used on a very limited scale in these studies, it seems likely that they could replace lethal tests for the diphtheria challenge assays.For both tetanus and diphtheria, the adsorbed toxoid gave a higher relative potency when combined with other antigens than as a single toxoid. Both mice and guinea-pigs were used for the lethal challenge test of adsorbed tetanus toxoid. For the single tetanus toxoid the results were the same, but for the combined toxoid (DPT vaccine) the mouse assay results were about twice those of guinea-pig assays.


Collaborative assay of a proposed international standard for tetanus toxoid (adsorbed)

February 1972

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18 Reads

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3 Citations

Bulletin of the World Health Organization

An international collaborative assay was performed with the aim of establishing an international standard for tetanus toxoid (adsorbed). Six laboratories participated. A suitable preparation in the lyophilized state was made available by the Paul Ehrlich Institut, Frankfurt am Main, Federal Republic of Germany. Preliminary experiments showed that there were no significant differences between individual ampoules and that the preparation was highly thermostable.The proposed preparation (A) was compared in guinea-pigs and mice with the existing international standard for tetanus toxoid (B), which is a plain toxoid, with another arbitrarily chosen adsorbed toxoid (C), and with a number of locally prepared preparations (D). In the mouse tests preparation B was omitted. It was found in the guinea-pig tests that 1 mg of the proposed standard contained an activity equivalent to 1.5 IU if compared with the non-adsorbed international standard but since the slopes of the log dose-response lines for the adsorbed and plain types of preparation were not parallel, this is a rough approximation only. When the different adsorbed preparations were compared, there was close correlation between the guinea-pig tests and the mouse tests. In the guinea-pig test 1 ml of preparation C corresponded to 126.5 mg of preparation A and in the mouse test to 129.9 mg of preparation A. In one laboratory comparative tests were made by titrating blood antitoxins after immunization of guinea-pigs with graded doses of the toxoids. The results corresponded very well with the data from challenge tests (1 mg of preparation A contained 1.5 IU of the plain toxoid in challenge tests and|1.4 IU in the titration test).Preparation A was established by the WHO Expert Committee on Biological Standardization as the international standard for tetanus toxoid (adsorbed) and the international unit was defined as the activity contained in 0.6667 mg of the international standard.


Titration of diphtheria and tetanus antitoxins in sera of low titre

February 1971

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25 Reads

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28 Citations

Bulletin of the World Health Organization

Available methods for titrating diphtheria and tetanus antitoxin at low concentrations in human or animal blood are surveyed, with special attention to the amount of serum required for the test.In vivo methods, especially the rabbit or guinea-pig intradermal test for diphtheria and the mouse test for tetanus, are precise and reliable. If, however, serum levels as low as about 0.001 IU/ml have to be determined, rather large amounts of serum are required: moreover, the tests are rather time-consuming and expensive.Tissue culture methods are available only for diphtheria antitoxin titration. The titres found coincide very well with those from animal tests. The titrations are less time-consuming and more economical. These methods seem to be very promising for the replacement of animal tests. Of the real in vitro methods, the haemagglutination procedure has been investigated most thoroughly and used most frequently. Low titres can be measured using small amounts of serum, but the titres thus obtained may differ considerably from those obtained in animal tests, at least for individual sera. For mass screening, the method is very suitable.A number of other methods are briefly discussed, but they are either less suitable or have not yet been sufficiently investigated.



Determination of diphtheria and tetanus antitoxin with the aid of haemagglutination

February 1960

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8 Reads

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20 Citations

Antonie van Leeuwenhoek

Summary A description is given of an investigation of the practical value of the determination of diphtheria and tetanus antitoxins by haemagglutination in sera from human sources. A detailed discussion of the methods used is followed by a report on the value of these methods as tested on 28 sera obtained from volunteers in the National Institute of Public Health. The titres obtained by these in-vitro methods were compared with the results of animal experiments. Correlation coefficients were calculated for the values obtained at different comparable levels of titration. These coefficients proved to be very satisfactory. General considerations regarding the nature and the object of such antitoxin determinations are presented and it is concluded that the haemagglutination technique described is useful in practice. This applies particularly to the titration of series of sera originating from one or several patients or from comparable groups of patients.



Consistency in potency assay of tetanus toxoid in mice

February 1959

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21 Reads

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13 Citations

Bulletin of the World Health Organization

The use of mice for the assay of tetanus toxoids would offer considerable advantages over the use of guinea-pigs, but mice cannot readily be immunized with the fluid tetanus toxoid at present designated as the International Standard. This study shows, however, that the mouse is a very suitable laboratory animal for the comparison of adsorbed tetanus toxoids, and that an AlPO(4)-adsorbed vaccine, which is stable at 4 degrees C, is a satisfactory reference preparation. The log-dose-response lines of toxoids adsorbed on different quantities of AlPO(4) and on various quantities of another adsorbent ran parallel to those of the reference vaccine. The 95% confidence limits for the potencies of tetanus vaccines, diphtheria-tetanus vaccines, and diphtheria-pertussis-tetanus vaccines, determined by assay against the reference vaccine in mice, showed a high degree of reproducibility of the results.


Potency and purification of tetanus toxoid obtained by means of the Mueller medium

February 1957

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6 Reads

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2 Citations

Antonie van Leeuwenhoek

A number of batches of tetanus toxin prepared by means of the ‘Mueller medium’ were fractionated with ammonium sulphate. The purity and the immunizing potency of the resulting fractions were determined. The fractions precipitated at low A.S. concentrations are very potent but not very pure, those precipitated at high A.S. concentrations have a low potency and are very impure. Medium concentrations (about 15–25% A.S.) yield a product which is highly satisfactory with respect to both purity and potency and forms a suitable basis for the preparation of a vaccine. The various batches of toxoid did not differ significantly in potency.


The flocculation of tetanus toxin and toxoid. II.

February 1955

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24 Reads

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1 Citation

Antonie van Leeuwenhoek

Summary 1. In the flocculation reaction of tetanus toxins prepared in a modified Tarozzi broth there appear five flocculation zones. 2. In addition to the “lowest flocculation” described in our previous paper, which corresponds with the antitoxin-binding (A.B.V.), we found another, still lower, flocculation, the value of which is about the same as the so-called maximal toxin value (M.T.V.). 3. A.B.V. was found to be from 2 to 5 times as high as M.T.V. 4. During the period of incubation all flocculation values show an initial rise, which is followed by a fall after 10–20 days. 5. Clostridium tetani produces a toxic and a non-toxic element, both binding antitoxin, but the latter having little, if any, immunizing effect.


The flocculation of tetanus toxin and toxoid. I

February 1954

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43 Reads

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3 Citations

Antonie van Leeuwenhoek

Summary 1. The flocculation of tetanus toxins and toxoids produced in a modified Tarozzi broth was made the subject of an exhaustive study. 2. At least three flocculation zones were found. 3. The lowest flocculation value always proved to agree with the true point of equivalence of the antitoxin-binding (A.B.V.). 4. When mixtures of toxin and antitoxin were injected into mice, only about half the total quantity of antitoxin that can be bound (as appears from A.B.V. or Lf) appeared to be required for the neutralization of the toxic effect. The quantity of toxin thus found was indicated as M.T.V. So this M.T.V. is approximately 1/2 A.B.V. or Lf. 5. During the incubation of tetanus cultures all flocculation values (3 or 4) increase steadily. 6. The d.l.m. also increases regularly, but much more quickly, hence the ratio m.l.d./Lf increases very considerably during incubation. 7. At the same time the ratio M.T.V./Lf remains constant, i.e. about 1/2. 8. The possible theoretical explanation of the different problems was discussed.


Citations (7)


... Identification of the strains was performed using an API Coryne kit (bioMérieux). The bacterial strains were cultivated on Loeffler medium (Kyokuto Pharmaceutical Industrial), sheep blood agar plates (Nissui Pharmaceutical), in iron-depleted Pope liquid medium (Tasman & Van Ramhorst, 1951;Tchorbanov et al., 2004) or brain heart infusion broth (Difco; Becton Dickinson). Japanese national reference diphtheria test toxin lot M59 was used as a control toxin. ...

Reference:

Two Japanese Corynebacterium ulcerans isolates from the same hospital: Ribotype, toxigenicity and serum antitoxin titre
On the relation between toxin production and protein synthesis byCorynebacterium diphtheriae and the iron content of the culture medium
  • Citing Article
  • December 1951

Antonie van Leeuwenhoek

... AlPO 4 or Al(OH) 3 ) and physical state (e.g. preformed precipitate or formation of precipitate in situ with the toxoid) of adjuvant [20], the interaction between one or more components in a combined vaccine [21e23], and the choice of assay system used to determine potency in vivo [18,24,25]. The situation is complicated further in that TTxd is used as a carrier protein in several polysaccharide conjugate vaccines, and Hib polysaccharide conjugated to TTxd is present in some combined vaccine products that also contain conventional (i.e. ...

International collaborative studies on potency assays of diphtheria and tetanus toxoids
  • Citing Article
  • February 1972

Bulletin of the World Health Organization

... However, the tetanus antitoxin IU was twice the AU, which continued until 1949, when the AU was adjusted to be equivalent to the IU. 23,24 Around the same time that antitoxin standards were accepted as international standards, Sir Henry Dale from the National Institute for Medical Research (NIMR), London, defined the international standard for insulin in IU in 1925 10,14,15,25 (Table 2), which enabled the widespread manufacture and clinical use of safe and effective insulin products worldwide. 25 The Establishment of a Permanent Commission on Biological Standardization under the League of Nations. ...

Titration of diphtheria and tetanus antitoxins in sera of low titre
  • Citing Article
  • February 1971

Bulletin of the World Health Organization

... In the past, many workers have directed themselves to the task of isolating a staphylococcal toxin with varying degrees of success. Some of the chemical methods employed were precipitation by acetic acid (4), ammonium sulfate (5,6,10,15,16,20), trichloracetic acid (21,22), acetone followed by trichloracetic acid (7), phosphoric acid (10), methanol (8,9,19), ethanol (6,10,18,20), and cellosolve (6,19). Physical methods such as chromatography (10-12, 15, 16, 18), various electrophoretic techniques (6,10,13,15,16,18,20), and ultracentrifugation (14), have also been applied to the problem of isolating various staphylococcal toxins. ...

On the purification and absorption of Staphylococcus toxoid
  • Citing Article
  • February 1952

Antonie van Leeuwenhoek

A TASMAN

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A C BRANDWIJK

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A MARSEILLE

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[...]

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J VAN DER SLOT

... The IHA test, like the agglutination reactions, is more efficient in assaying IgM antibodies [1]. Therefore, IHA titres are generally higher than the neu tralizatilln titres of the sera [22][23][24][59][60][61][62] because the neutralization method measure, IgG only [63]. The treatment of test sera with 2-mercaptoethanol, a disulphi.le ...

Determination of diphtheria and tetanus antitoxin with the aid of haemagglutination
  • Citing Article
  • February 1960

Antonie van Leeuwenhoek

... TTd vaccines are stable for years, but temperature exposure can accelerate loss of potency [18,19]. Exposure to 55 • C for three days has been reported to decrease TTd potency by 48%, whereas exposure to 53 • C for four days only decreased potency by 17%, indicating a turning point in TTd stability near these temperatures [20]. For our aberrant samples, we chose temperatures that would cover this range. ...

Consistency in potency assay of tetanus toxoid in mice
  • Citing Article
  • February 1959

Bulletin of the World Health Organization