Distribution of histamine among leukocytes and platelets

1. Platelets and lymphocytes free of other white elements of blood have beenanalysed for histamine by a microchemical method. Platelets were found to contain 1280 µg. per liter or .009 µg. per 10⁹ platelets, lymphocytes 2600 µg. perliter, or 0.6 µg. per 10⁹ cells.

2. The histamine content of neutrophilic, eosinophilic and basophilic granulocytes has been calculated by multiple regression from histamine measurementson one series of blood samples from normal adults and another from subjectswith chronic myelocytic leukemia. The normal values are 1080 µg. per l0⁹basophils and 160 µg. per 10⁹ eosinophils or 2,400,000 and 360,000 µg. per literrespectively. The corresponding values for neutrophils are 3 µg. per 10⁹ cellsand 7000 µg. per liter. The values for the histamine concentration per cell arestatistically significant for basophils and eosinophils, but not for neutrophils.

In the leukemia series, the values for neutrophils and basophils are respectively69 and 305 µg. per 10⁹ cells, and they are statistically significant. The differencefrom normal in the value for basophils was not statistically validated. There are,however, in chronic myelocytic leukemia, histological changes from the normalthat are consonant with a decreased histamine content in basophils and an increased histamine content in eosinophils and neutrophils.

3. Although definite values for the histamine content of monocytes and theimmature forms seen in chronic myelocytic leukemia have not been obtained,there is reason to believe that the histamine of these cell types does not exceedthat of neutrophils.

4. By centrifuging white cells in a specific gravity gradient column, partialsegregation of cell types was obtained. Peak concentrations were observed at thefollowihig specific gravities: lymphocytic leukemia lymphocytes, 1.063; myelocytes, normal lymphocytes and basophils, all near 1.070; neutrophils, 1.080,and eosinophils, 1.080 or higher. Although individual concentration peaks wereusually quite sharp, there was considerable overlapping at intermediate specificgravities.

5. About half of the histamine of normal blood is in the basophils, one-thirdin the eosinophils and the remaining one-sixth in all the other blood elementscombined. In blood samples from patients with chronic myelocytic leukemia,the fraction of blood histamine carried by each type of granulocyte varies widely.

Submitted on September 20, 1954 Accepted on October 11, 1954     

PREDICTION OF THE SEVERITY OF ABO HAEMOLYTIC DISEASE OF THE NEWBORN BY CORD BLOOD TESTS

ABSTRACT. Whyte, J. and Graham, H. (Bellshill Maternity Hospital, Bellshill, Lanarkshire, Scotland). Prediction of the severity of ABO haemolytic disease of the newborn by cord blood tests. Acta Paediatr Scand, 70:217, 1981. –Seventy-one ABO incompatible (heterospecific) infants and 71 controls, who were free from other potential causes of jaundice, were studied to ascertain which cord blood tests reliably predict the severity of ABO haemolytic disease of the newborn (ABO HDN). The modified Direct Antiglobulin Test (spin DAGT) was positive in all infants who required treatment for haemolytic jaundice and only DAGT positive children showed evidence of impending haemolytic anaemia or compensated haemolysis in cord or capillary blood. Cord serum bilirubin concentration had some predictive value, particularly when the level exceeded 85 µmol/l, but it was a less reliable indicator and had greater value if used in association with the DAGT. The elution test, which is frequently used as a diagnostic tool in ABO HDN, had no predictive value and we felt that its putative value is due to overdiagnosis of ABO HDN in jaundiced heterospecific infants. We conclude that the spin DAGT, despite the weakness of the reaction, reliably identifies infants at risk from severe ABO HDN and is sufficiently sensitive to be used as a single screening test for the early detection of the disorder.     

Interobserver variation in the interpretation of abdominal radiographs

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.     

Effect of intersection spacing on MR image contrast and study time

The effects of section separation on image contrast and calculated T1 relaxation times were investigated in healthy volunteers and a phantom using an early commercial version magnetic resonance imaging system. The effects are explained qualitatively on the basis of side lobes of excitation occurring outside the selected section resulting in reduction of the time permitted for T1 relaxation. The options for dealing with imperfect section selection, including separation of the sections (i.e., leaving gaps) and nonsequential excitation, are illustrated and the trade-offs involved in each explained.     

CUTANEOUS VASCULITIS DUE TO CYCLOPHOSPHAMIDE THERAPY FOR CHRONIC LYMPHOCYTIC LEUKEMIA

A 55-year-old male with chronic lymphocytic leukemia developed a skin eruption after receiving oral cyclophosphamide. Subsequent rechallenge with parenteral cyclophosphamide led to recurrence of the skin lesions, which on biopsy were shown to be vasculitic in nature. (Aust NZ J Med 1989; 19: 55–57.)