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Koch's postulates: Revisited or revised?
704
Letters
unless there was a product failure of the Rh immune globulin. To the best of our knowledge, there have been no reported failures of the product and lot number that our patient received. Next, why was the antibody screen for our patient negative at 10 weeks' and at 15 weeks' gestation if the patient presumably was sensitized from a bleeding episode at 8.5 weeks' gestation? This is an extremely important point for clinical obstetricians. First, it requires several weeks for a primary response to a blood-group antibody to be detectable. 3 Second, we reponed that the IS-week antibody screen for our patient was only performed with low ionic strength saline solution and without any enzyme enhancement. The anti-D antibody frequently requires enzyme enhancement to be detected if it is weak or developing' (as it would be at 15 weeks' gestation in our patient). For this reason, many laboratories routinely use enzyme enhancement for all obstetric antibody screening. We are confident that lack of enzyme enhancement was the reason that the seroconversion was not detected at 15 weeks' gestation in our patient. As to whether or not this patient could have been sensitized as a result of small transplacental hemorrhages between the fifteenth and twenty-eighth gestational weeks, we again contend that the full dose of Rh immune globulin was more than ample to cover any bleeding from the amniocentesis at 15 weeks' gestation, and sufficient Rh immune globulin should have been present to cover any minor bleeding episodes between that time and 28 weeks' gestation. Again, we thank you for giving us this opportunity to clarify these important points. We would also again like to question why it is that the American College of Obstetrics and Gynecology recommends the routine use of Rh immune globulin after chorionic villus sampling in the first trimester but not for spontaneous transplacental bleeding during the same time period! Until a study such as the one Dr. Kuller mentions indicates otherwise, we will continue to recommend that our physicians give Rh immune globulin to women with the Rho(D)-negative blood type who have first-trimester bleeding whether or not they go on to abort spontaneously. Vanessa D. Dayton, MD,* Deborah S. Anderson, BS, John T. Crosson, MD, and Stephen H. Cruikshank, MD Departments of Laboratory Medicine and Pathology and Obstetrics and Gynecology, Hennepin County Medical Center, Minneapolis, MN 55415
February 1991 Am J Obstet Gynecol
Koch's postulates: Revisited or revised? To the Editors: During my years as an obstetriciangynecologist, I have come to view the GRAY JOURNAL as the preeminent publication in our specialty. I have believed that the JOURNAL has set the standard for publications in our specialty. I am sure that our colleagues throughout the world agree. It is therefore with a sense of dismay that I write this letter to you regarding a recently published article [Wiggins DA, Elliott JP. Oligohydramnios in each sac of a triplet gestation caused by Motrin-Fulfilling Kock's postulates (italics added). AM J OBSTET GYNECOL 1990;162:460-1]. It is, perhaps, that as I grow older my natural tendencies as a gadfly bec~me more pronounced or, perhaps, my sense of purism is disturbed by historic inaccuracies, to wit: In 1882, Robert Koch, a Nobel Laureate in 1905, formalized the criteria that established the pathogenic character of a microorganism from that of an adventitious microbe. This statement became known as "Koch's postulates" (Koch R. Berl Klin Wochenschr 1882;19:221-30). These formalized criteria, which were introduced by Henle in 1840, state: (1) The organism is regularly found in lesions of the disease; (2) it can be isolated in pure culture on artificial media; (3) inoculation of this culture produces a similar disease in experimental animals; (4) the organism can be recovered from the lesions in these animals. How the above could be unappreciated by the authors (who did not even present a reference to these "postulates") and how this could be overlooked and accepted by the Editors of the JOURNAL without comment is startling. Indeed, repeatedly the name Koch is misspelled as Kock. I do not take offense with the fact that the authors wish to establish an appropriate deductive path to establish their case for the relationship of Motrin to oligohydramnios. However, it would have been preferable for them to use some approach other than the application of a set of principles that relates to microbial pathogenicity. This editorial oversight is upsetting! Thank you for patience in reviewing this matter. Burton A. Krumholz, MD Professor of Gynecology and Obstetrics, Albert Einstein College of Medicine, Long Island Jewish Medical Center, New Hyde Park, NY
11042
Response declined
REFERENCES 1. Cunningham FG, MacDonald PC, Grant NF. Williams obstetrics, 18th ed. East Norwalk, Conn.: Appleton and Lange, 1989: 10 l. 2. Arey LB. Developmental anatomy, 7th ed. Philadelphia: W.B. Saunders, 1974:104. 3. Walker RH, et al. Technical manual, 10th ~d. Arlington, Va.: American Association of Blood Banks, 1990: 130,211, 402. 4. American College of Obstetricians and Gynecologists. Prevention of Rho (D) isoimmunization. ACOG Tech Bull 1984:August 1979.
Frontothalamic measurement in the second trimester of pregnancy To the Editors: After we read the report of Goldstein, which was published in the JOURNAL in 1988 (Goldstein I, Reece EA, Pilu G, O'Connor TZ, Lockwood CJ, Hobbins JC. So no graphic assessment of the frontal lobe: A potential tool for prenatal diagnosis of microcephaly. AM J OBSTET GYNECOL 1988;158:1057-62) and which detailed a new fetal brain measurement, the
Letters
unless there was a product failure of the Rh immune globulin. To the best of our knowledge, there have been no reported failures of the product and lot number that our patient received. Next, why was the antibody screen for our patient negative at 10 weeks' and at 15 weeks' gestation if the patient presumably was sensitized from a bleeding episode at 8.5 weeks' gestation? This is an extremely important point for clinical obstetricians. First, it requires several weeks for a primary response to a blood-group antibody to be detectable. 3 Second, we reponed that the IS-week antibody screen for our patient was only performed with low ionic strength saline solution and without any enzyme enhancement. The anti-D antibody frequently requires enzyme enhancement to be detected if it is weak or developing' (as it would be at 15 weeks' gestation in our patient). For this reason, many laboratories routinely use enzyme enhancement for all obstetric antibody screening. We are confident that lack of enzyme enhancement was the reason that the seroconversion was not detected at 15 weeks' gestation in our patient. As to whether or not this patient could have been sensitized as a result of small transplacental hemorrhages between the fifteenth and twenty-eighth gestational weeks, we again contend that the full dose of Rh immune globulin was more than ample to cover any bleeding from the amniocentesis at 15 weeks' gestation, and sufficient Rh immune globulin should have been present to cover any minor bleeding episodes between that time and 28 weeks' gestation. Again, we thank you for giving us this opportunity to clarify these important points. We would also again like to question why it is that the American College of Obstetrics and Gynecology recommends the routine use of Rh immune globulin after chorionic villus sampling in the first trimester but not for spontaneous transplacental bleeding during the same time period! Until a study such as the one Dr. Kuller mentions indicates otherwise, we will continue to recommend that our physicians give Rh immune globulin to women with the Rho(D)-negative blood type who have first-trimester bleeding whether or not they go on to abort spontaneously. Vanessa D. Dayton, MD,* Deborah S. Anderson, BS, John T. Crosson, MD, and Stephen H. Cruikshank, MD Departments of Laboratory Medicine and Pathology and Obstetrics and Gynecology, Hennepin County Medical Center, Minneapolis, MN 55415
February 1991 Am J Obstet Gynecol
Koch's postulates: Revisited or revised? To the Editors: During my years as an obstetriciangynecologist, I have come to view the GRAY JOURNAL as the preeminent publication in our specialty. I have believed that the JOURNAL has set the standard for publications in our specialty. I am sure that our colleagues throughout the world agree. It is therefore with a sense of dismay that I write this letter to you regarding a recently published article [Wiggins DA, Elliott JP. Oligohydramnios in each sac of a triplet gestation caused by Motrin-Fulfilling Kock's postulates (italics added). AM J OBSTET GYNECOL 1990;162:460-1]. It is, perhaps, that as I grow older my natural tendencies as a gadfly bec~me more pronounced or, perhaps, my sense of purism is disturbed by historic inaccuracies, to wit: In 1882, Robert Koch, a Nobel Laureate in 1905, formalized the criteria that established the pathogenic character of a microorganism from that of an adventitious microbe. This statement became known as "Koch's postulates" (Koch R. Berl Klin Wochenschr 1882;19:221-30). These formalized criteria, which were introduced by Henle in 1840, state: (1) The organism is regularly found in lesions of the disease; (2) it can be isolated in pure culture on artificial media; (3) inoculation of this culture produces a similar disease in experimental animals; (4) the organism can be recovered from the lesions in these animals. How the above could be unappreciated by the authors (who did not even present a reference to these "postulates") and how this could be overlooked and accepted by the Editors of the JOURNAL without comment is startling. Indeed, repeatedly the name Koch is misspelled as Kock. I do not take offense with the fact that the authors wish to establish an appropriate deductive path to establish their case for the relationship of Motrin to oligohydramnios. However, it would have been preferable for them to use some approach other than the application of a set of principles that relates to microbial pathogenicity. This editorial oversight is upsetting! Thank you for patience in reviewing this matter. Burton A. Krumholz, MD Professor of Gynecology and Obstetrics, Albert Einstein College of Medicine, Long Island Jewish Medical Center, New Hyde Park, NY
11042
Response declined
REFERENCES 1. Cunningham FG, MacDonald PC, Grant NF. Williams obstetrics, 18th ed. East Norwalk, Conn.: Appleton and Lange, 1989: 10 l. 2. Arey LB. Developmental anatomy, 7th ed. Philadelphia: W.B. Saunders, 1974:104. 3. Walker RH, et al. Technical manual, 10th ~d. Arlington, Va.: American Association of Blood Banks, 1990: 130,211, 402. 4. American College of Obstetricians and Gynecologists. Prevention of Rho (D) isoimmunization. ACOG Tech Bull 1984:August 1979.
Frontothalamic measurement in the second trimester of pregnancy To the Editors: After we read the report of Goldstein, which was published in the JOURNAL in 1988 (Goldstein I, Reece EA, Pilu G, O'Connor TZ, Lockwood CJ, Hobbins JC. So no graphic assessment of the frontal lobe: A potential tool for prenatal diagnosis of microcephaly. AM J OBSTET GYNECOL 1988;158:1057-62) and which detailed a new fetal brain measurement, the