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MYOID CELLS IN HUMAN THYMUS
1320 support of their explanation of the plateau. They make no effort to give a detailed classification of the causes of the stillbirths they record, or information on the proportion which occurred in patients receiving general-practitioner antenatal " care. Statistics improperly handled can be made to prove " any preconceived notion, and I would suggest that this article is a classic example of such a technique. CYRIL HART.
MYOID CELLS IN HUMAN THYMUS SIR,-Three contributions have mentioned the presence of cells, resembling striated muscle cells, in thymus tissue: Dr. van der Geld and Dr. Strauss (Jan. 8) describe the concordance of antibodies against striated muscle and thymus epithelial cells, pointing to common antigens in these tissues, and in an addendum refer to a personal communication from Van de Velde et al. on the existence of myoid cells in thymus tissue; Dr. Henry (Jan. 22) describes striated muscle cells in human foetal and perinatal thymus; and Dr. Strauss and his colleagues (April 2) note that myoid cells, present in abundant quantity in turtle thymus, have an antigen in common with skeletal muscle.
(A.T.P.a.), stimulated by calcium ions (A.T.P.a.-Ca).1 2With the same methods calf-thymus tissue showed myoid cells. Finally I tried these staining techniques on biopsy specimens of thymus tissue from two patients, a man of 31 and a woman of 40 years, who had no symptoms of autoimmune disease. I found normal involuted thymus tissue in which myoid cells, rounded or with head-and-tail configuration, could be demonstrated, especially at the borders of the thymus-tissue remnants, where at an earlier age the corticomedullary junction had been situated; these cells sometimes showed striations (fig. 2). All material mentioned above was simultaneously studied with the indirect immunofluorescent techniquewith sera containing antibodies against skeletal muscle tissue. With the aid of serial sections it could be proved that all the A.T.P.a.-Ca1. 2. 3.
Padykula, H. A., Herman, E. J. Histochem. Cytochem. 1955, 3, 161, 170. Wachstein, M., Meisel, E. Am. J. clin. Path. 1957, 27, 13. Feltkamp, T. E. W., van der Geld, H., Oosterhuis, H. J. G. H. Vox sang, 1963, 8, 317.
Intrigued by these findings I have investigated chicken, calf, and human thymus tissue. In adult chicken thymus, myoid cells were present and very well stainable with, for example, Heidenhain-Azan or Gomori-trichrome staining techniques. These cells sometimes showed rounded forms in which it was often possible to find concentric structures; at other times long muscle-cell-like forms or so-called head-and-tail configurations with striations could be seen (fig. 1). Histochemical techniques demonstrated very strong activity of adenosine triphosphatase
1-Adult chicken thymus: (a) formalin-fixed and paraffinembedded with Gomori-trichrome stain showing myoid cells, some rounded, and one elongated with cross-striations; (b) A.T.P.a.-Ca-positive myoid cell, elongated with cross-striations; (c) Azan-staining after fixation of cryostat section, showing several striated myoid cells, rounded or elongated. ( x 500.)
Fig.
Fig. 2-Cryostat sections of normal adult human thymus: (a) A.T.P.a.-Ca-positive myoid cells, localised especially at borders of thymus-tissue remnants (x65); (b) and (c) A.T.P.a.-Capositive myoid cells with head-and-tail configuration or rounded forms (x 200 and x 500 respectively); (d) Azan-staining after fixation, showing head-and-tail configuration (x500).
1321
positive cells were good antigens for antibodies directed against skeletal muscle tissue. Thus
myoid cells
can
be found in adult human
thymus tissue
and they are most likely identical with the so-called "epithelial" cells, described by Dr. van der Geld and Dr. Strauss and by van der Geld et al.,4 containing the skeletal-muscle antigen. Laboratory of Immunopathology, University of Amsterdam, and Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, P.O. Box 200, Amsterdam.
THEA FELTKAMP-VROOM.
NEUROTOXIC SIDE-EFFECTS OF PIPERAZINES SIR,-Single-dose treatment with piperazine (for threadworms and round worms) is probably the lesson to be derived from the report (May 28) from Dr. Schuch and his colleagues. Because no other treatment for threadworm and round-worm infections has the record of reliability and safety which piperazine has earned during the past 12 years, it would be useful to be told the doses which they gave and the number of children they treated in their series in which toxic effects were sometimes seen on the 2nd to 5th day of treatment with
Typical
piperazine hexahvdrate.
the
Guy’s Hospital, London S.E.1.
RONALD MAC KEITH
SERUM-INSULIN AND GLUCAGON DURING GLUCOSE-TOLERANCE TEST
SiR,-Attempts similar to those of Samols et al.5 have been made at this hospital to measure simultaneous levels of bloodsugar, insulin, and glucagon at frequent intervals in 15 healthy volunteers, 3 obese diabetics and 3 patients with diabetes mellitus. The volunteers and the patients were maintained on a highcarbohydrate diet for four days, and then fasted for twelve hours before the test. After the patient had rested in bed for an hour, a fasting blood-sample was obtained. After the oral administration of 100 ml. of 50% dextrose solution, 8 ml. blood-samples were taken at intervals sof ten to fifteen minutes. A modified Hagedorn and Jensen technique was used for blood-sugar determinations. The serum-insulin and glucagon were assayed by a modification of the method of Meade and Klitgaardfor serum-insulin. In our method, an index of the hormone concentration was obtained by the percentage of resin-bound radioactively labelled hormone. This was converted to normal units of the hormone by comparison with known standards set up in 3-75% gelatine solution. These methods have been described in greater detail elsewhere.8 Throughout, we bore in mind that the estimations of insulin and glucagon would be invalid if the antibodies prepared for each of these hormones were not sufficiently specific. In view of the chemical similarity of glucagon and insulin,9 a lack of specificity could result in the immunoassay yielding the combined concentration of both hormones. The complete difference, however, in form of the curves for serum-insulin and glucagon in the accompanying figure-a typical result in a healthy volunteer-suggests that the immunoassay technique does in fact measure insulin and glucagon separately. In the fasting state, blood-sugar levels were found to range from 70-110 mg. per 100 ml. Glucagon levels were fairly high (40-80 mug. per ml.) whereas those of insulin were relatively low (10-30 fly per ml.). After the ingestion of glucose, bloodsugar levels increased and reached a peak of 120-160 mg. per 100 ml. about thirty minutes later. At the same time, seruminsulin levels rose from less than 30 fLU per ml. to peaks of 70-130 J:LlJyer ml. at about thirty minutes. During this period, 4.
van der Geld, H., Feltkamp, T. E. W., Oosterhuis, H. J. G. H. Proc. Soc. exp. Biol. Med. 1964, 115, 782. 5. Samols, E., Tyler, J., Marri, G., Marks, V. Lancet, 1965, ii, 1257. 6. Hagedorn, J., Halstrom, B., Jensen, T. Rep. Steno meml Hosp. 1946, i, 29. 7. Meade, R. C., Klitgaard, H. M. J. nucl. Med. 1962, 2, 407. 8. Young, J. D., Biddlecombe, D. K. Aust. J. Sci. 1966 (in the press). 9. Dail, D. H., Richmond, J. E. Nature, Lond. 1966, 66, 302.
curves
in
a
healthy volunteer during oral glucose-tolerance
test.
Blood-sugar (mg. per 100 ml.). (fLU per ml.). X Serum-glucagon (mg. per ml.). .
0
Serum-insulin
serum-glucagon decreased to its lowest level (range 10-30 mg. per ml.) at about sixty minutes. In most of the healthy volunteers the oscillations were apparent for only two or three cycles, but in some they persisted for five or more cycles. In the few obese diabetics, the levels of blood-sugar and insulin with only slow variations remained high throughout. The glucagon levels remained negligible throughout. Patients with diabetes mellitus had high levels of blood-sugar and low levels of both insulin and glucagon in the fasting state and throughout the test. These results and their greater detail elsewhere.
interpretation
will be described in
Physics Department, St. Vincent’s Hospital, Sydney, New South Wales, Australia.
J. D. YOUNG I. S.
JENKINSON.
POSTOPERATIVE INFECTION WITH PSEUDOMONAS AERUGINOSA IN AN EYE HOSPITAL SIR,-The article by Dr. Ayliffe and others (May 21) reveals a lack of informed medical supervision of the methods used in the dispensary. As an undergraduate thirty years ago, I was taught that the " sterilisation " of syringes in antiseptic fluid was unsafe and long outdated. The Birmingham report now acknowledges that the solutions used for intraocular operations should be sterilised in their final containers and provided as single doses; but Dr. Ayliffe and his colleagues believe that, for practical reasons, this ideal cannot yet be attained. As this simple method has been used at the Royal Adelaide Hospital for the past nine years, there can be no valid reason for the continued failure to do this in Birmingham, where the theatres should not be used until it is achieved. In South Australia, even suburban dispensing chemists with the help of a pressure cooker1 provide safe eyedrops. Your editorial of May 21 mentions that the 1966 Supplement to the British Pharmaceutical Codex sets out completely new formulations for all eyedrops in which better bactericides replace the hydroxybenzoates. This aspect, however, is of little importance when discussing eye solutions to be used in operating-theatres, for these should be sterilised in their final single-dose containers without preservatives if their introduction into the anterior chamber is likely. Unfortunately, your editorial fails to note the outstanding innovation of this Supplement which significantly states that " eyedrops are sterile solutions and comply with the tests for sterility " adopting as " Method A: the sterilization of solutions in the final containers by heating in an autoclave ". Perhaps the most important point in the article by Dr. 1.
Jeffs, P. L. Aust. J. Pharmacy, Oct. 30, 1962.
MYOID CELLS IN HUMAN THYMUS SIR,-Three contributions have mentioned the presence of cells, resembling striated muscle cells, in thymus tissue: Dr. van der Geld and Dr. Strauss (Jan. 8) describe the concordance of antibodies against striated muscle and thymus epithelial cells, pointing to common antigens in these tissues, and in an addendum refer to a personal communication from Van de Velde et al. on the existence of myoid cells in thymus tissue; Dr. Henry (Jan. 22) describes striated muscle cells in human foetal and perinatal thymus; and Dr. Strauss and his colleagues (April 2) note that myoid cells, present in abundant quantity in turtle thymus, have an antigen in common with skeletal muscle.
(A.T.P.a.), stimulated by calcium ions (A.T.P.a.-Ca).1 2With the same methods calf-thymus tissue showed myoid cells. Finally I tried these staining techniques on biopsy specimens of thymus tissue from two patients, a man of 31 and a woman of 40 years, who had no symptoms of autoimmune disease. I found normal involuted thymus tissue in which myoid cells, rounded or with head-and-tail configuration, could be demonstrated, especially at the borders of the thymus-tissue remnants, where at an earlier age the corticomedullary junction had been situated; these cells sometimes showed striations (fig. 2). All material mentioned above was simultaneously studied with the indirect immunofluorescent techniquewith sera containing antibodies against skeletal muscle tissue. With the aid of serial sections it could be proved that all the A.T.P.a.-Ca1. 2. 3.
Padykula, H. A., Herman, E. J. Histochem. Cytochem. 1955, 3, 161, 170. Wachstein, M., Meisel, E. Am. J. clin. Path. 1957, 27, 13. Feltkamp, T. E. W., van der Geld, H., Oosterhuis, H. J. G. H. Vox sang, 1963, 8, 317.
Intrigued by these findings I have investigated chicken, calf, and human thymus tissue. In adult chicken thymus, myoid cells were present and very well stainable with, for example, Heidenhain-Azan or Gomori-trichrome staining techniques. These cells sometimes showed rounded forms in which it was often possible to find concentric structures; at other times long muscle-cell-like forms or so-called head-and-tail configurations with striations could be seen (fig. 1). Histochemical techniques demonstrated very strong activity of adenosine triphosphatase
1-Adult chicken thymus: (a) formalin-fixed and paraffinembedded with Gomori-trichrome stain showing myoid cells, some rounded, and one elongated with cross-striations; (b) A.T.P.a.-Ca-positive myoid cell, elongated with cross-striations; (c) Azan-staining after fixation of cryostat section, showing several striated myoid cells, rounded or elongated. ( x 500.)
Fig.
Fig. 2-Cryostat sections of normal adult human thymus: (a) A.T.P.a.-Ca-positive myoid cells, localised especially at borders of thymus-tissue remnants (x65); (b) and (c) A.T.P.a.-Capositive myoid cells with head-and-tail configuration or rounded forms (x 200 and x 500 respectively); (d) Azan-staining after fixation, showing head-and-tail configuration (x500).
1321
positive cells were good antigens for antibodies directed against skeletal muscle tissue. Thus
myoid cells
can
be found in adult human
thymus tissue
and they are most likely identical with the so-called "epithelial" cells, described by Dr. van der Geld and Dr. Strauss and by van der Geld et al.,4 containing the skeletal-muscle antigen. Laboratory of Immunopathology, University of Amsterdam, and Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, P.O. Box 200, Amsterdam.
THEA FELTKAMP-VROOM.
NEUROTOXIC SIDE-EFFECTS OF PIPERAZINES SIR,-Single-dose treatment with piperazine (for threadworms and round worms) is probably the lesson to be derived from the report (May 28) from Dr. Schuch and his colleagues. Because no other treatment for threadworm and round-worm infections has the record of reliability and safety which piperazine has earned during the past 12 years, it would be useful to be told the doses which they gave and the number of children they treated in their series in which toxic effects were sometimes seen on the 2nd to 5th day of treatment with
Typical
piperazine hexahvdrate.
the
Guy’s Hospital, London S.E.1.
RONALD MAC KEITH
SERUM-INSULIN AND GLUCAGON DURING GLUCOSE-TOLERANCE TEST
SiR,-Attempts similar to those of Samols et al.5 have been made at this hospital to measure simultaneous levels of bloodsugar, insulin, and glucagon at frequent intervals in 15 healthy volunteers, 3 obese diabetics and 3 patients with diabetes mellitus. The volunteers and the patients were maintained on a highcarbohydrate diet for four days, and then fasted for twelve hours before the test. After the patient had rested in bed for an hour, a fasting blood-sample was obtained. After the oral administration of 100 ml. of 50% dextrose solution, 8 ml. blood-samples were taken at intervals sof ten to fifteen minutes. A modified Hagedorn and Jensen technique was used for blood-sugar determinations. The serum-insulin and glucagon were assayed by a modification of the method of Meade and Klitgaardfor serum-insulin. In our method, an index of the hormone concentration was obtained by the percentage of resin-bound radioactively labelled hormone. This was converted to normal units of the hormone by comparison with known standards set up in 3-75% gelatine solution. These methods have been described in greater detail elsewhere.8 Throughout, we bore in mind that the estimations of insulin and glucagon would be invalid if the antibodies prepared for each of these hormones were not sufficiently specific. In view of the chemical similarity of glucagon and insulin,9 a lack of specificity could result in the immunoassay yielding the combined concentration of both hormones. The complete difference, however, in form of the curves for serum-insulin and glucagon in the accompanying figure-a typical result in a healthy volunteer-suggests that the immunoassay technique does in fact measure insulin and glucagon separately. In the fasting state, blood-sugar levels were found to range from 70-110 mg. per 100 ml. Glucagon levels were fairly high (40-80 mug. per ml.) whereas those of insulin were relatively low (10-30 fly per ml.). After the ingestion of glucose, bloodsugar levels increased and reached a peak of 120-160 mg. per 100 ml. about thirty minutes later. At the same time, seruminsulin levels rose from less than 30 fLU per ml. to peaks of 70-130 J:LlJyer ml. at about thirty minutes. During this period, 4.
van der Geld, H., Feltkamp, T. E. W., Oosterhuis, H. J. G. H. Proc. Soc. exp. Biol. Med. 1964, 115, 782. 5. Samols, E., Tyler, J., Marri, G., Marks, V. Lancet, 1965, ii, 1257. 6. Hagedorn, J., Halstrom, B., Jensen, T. Rep. Steno meml Hosp. 1946, i, 29. 7. Meade, R. C., Klitgaard, H. M. J. nucl. Med. 1962, 2, 407. 8. Young, J. D., Biddlecombe, D. K. Aust. J. Sci. 1966 (in the press). 9. Dail, D. H., Richmond, J. E. Nature, Lond. 1966, 66, 302.
curves
in
a
healthy volunteer during oral glucose-tolerance
test.
Blood-sugar (mg. per 100 ml.). (fLU per ml.). X Serum-glucagon (mg. per ml.). .
0
Serum-insulin
serum-glucagon decreased to its lowest level (range 10-30 mg. per ml.) at about sixty minutes. In most of the healthy volunteers the oscillations were apparent for only two or three cycles, but in some they persisted for five or more cycles. In the few obese diabetics, the levels of blood-sugar and insulin with only slow variations remained high throughout. The glucagon levels remained negligible throughout. Patients with diabetes mellitus had high levels of blood-sugar and low levels of both insulin and glucagon in the fasting state and throughout the test. These results and their greater detail elsewhere.
interpretation
will be described in
Physics Department, St. Vincent’s Hospital, Sydney, New South Wales, Australia.
J. D. YOUNG I. S.
JENKINSON.
POSTOPERATIVE INFECTION WITH PSEUDOMONAS AERUGINOSA IN AN EYE HOSPITAL SIR,-The article by Dr. Ayliffe and others (May 21) reveals a lack of informed medical supervision of the methods used in the dispensary. As an undergraduate thirty years ago, I was taught that the " sterilisation " of syringes in antiseptic fluid was unsafe and long outdated. The Birmingham report now acknowledges that the solutions used for intraocular operations should be sterilised in their final containers and provided as single doses; but Dr. Ayliffe and his colleagues believe that, for practical reasons, this ideal cannot yet be attained. As this simple method has been used at the Royal Adelaide Hospital for the past nine years, there can be no valid reason for the continued failure to do this in Birmingham, where the theatres should not be used until it is achieved. In South Australia, even suburban dispensing chemists with the help of a pressure cooker1 provide safe eyedrops. Your editorial of May 21 mentions that the 1966 Supplement to the British Pharmaceutical Codex sets out completely new formulations for all eyedrops in which better bactericides replace the hydroxybenzoates. This aspect, however, is of little importance when discussing eye solutions to be used in operating-theatres, for these should be sterilised in their final single-dose containers without preservatives if their introduction into the anterior chamber is likely. Unfortunately, your editorial fails to note the outstanding innovation of this Supplement which significantly states that " eyedrops are sterile solutions and comply with the tests for sterility " adopting as " Method A: the sterilization of solutions in the final containers by heating in an autoclave ". Perhaps the most important point in the article by Dr. 1.
Jeffs, P. L. Aust. J. Pharmacy, Oct. 30, 1962.