Pulse oximetry in sickle cell disease.

The place of pulse oximetry in monitoring arterial oxygen saturation in sickle cell disease has been evaluated. In four admissions of patients with sickle cell anaemia with varying degrees of arterial haemoglobin oxygen desaturation, pulse oximetry was compared with a simultaneous assessment of oxygen saturation by arterial blood gas measurement and oxygen dissociation curve (ODC) analysis. Close agreement was found between the oxygen saturation measured by pulse oximetry and that calculated from the measured arterial partial pressure of oxygen (PaO2) with reference to the patient's own ODC. Calculation of oxygen saturation by the blood gas analyser assuming a normal ODC was erroneous. Pulse oximetry is an accurate and effective non-invasive method for monitoring the arterial oxygen saturation in sickle cell disease.

Monosomy 7 and Ph-positive acute lymphoblastic leukaemia: cytogenetic and molecular aspects.

A combination of monosomy 7 and translocation t(9;22) (q34;q11), rarely observed in acute lymphoblastic leukaemia (ALL), is here reported: a peculiarity of this case was that the "breakpoint cluster region" on chromosome 22 was not rearranged, as demonstrated by molecular analysis, and a new c-abl protein (p190) was found, instead of the usual p210 protein usually associated with the Ph chromosome; moreover a rearrangement of c-abl oncogene was found. The clinical course of this patient was, as expected, unfavorable: a few normal metaphases were observed during a short partial remission.

Hypersplenism and splenectomy in lymphoproliferative and myeloproliferative disorders.

Splenic pooling of red cells and an expanded plasma volume are considered to be among the major mechanisms responsible for the anaemia in hypersplenism. In those conditions in which massive splenomegaly is associated with various degrees of marrow failure, diagnosis of the cause of anaemia may be difficult. A simple technique was used to estimate the degree of hypersplenism, from red cell mass data, in 94 patients with unequivocal lymphoproliferative or myeloproliferative disorders. The splenic effect was found to correlate well with both the size of the spleen (r = 0.75-0.90) and the actual red cell mass (0.79), and was abolished by splenectomy. Clinical data is also presented on 43 of these patients who underwent splenectomy. The incidence and type of complications, survival figures, and possible criteria for patient selection are discussed.

Acute lymphoblastic leukemia supervening in a case of chronic lymphocytic leukemia after continuous 3-year treatment with chlorambucil.

A case is presented of a patient with classical chronic lymphatic leukemia (CLL) treated with continuous chlorambucil for 3 years who presented with a picture of acute leukemia. The peripheral blood still showed a prevalence of mature lymphocytes with a few blast cells, whereas the bone marrow showed a predominant population of blast cells possessing a null acute lymphoblastic leukemia phenotype. Karyotype analysis showed a prevalent hyperdiploid clone of 67 to 68 chromosomes with endoreduplication and marker chromosomes. The coexistence of a CLL-type population with the blastic, undifferentiated cell clone suggests a second malignancy superimposed on the previous leukemic process, and possibly brought about by the continuous chlorambucil treatment.

Interpretation of measured red cell mass and plasma volume in males with elevated venous PCV values.

A method of interpretation of red cell mass (RCM) and plasma volume (PV) data is described. The results in 188 males with PCV's over 0.50 places the patients in 4 groups: true (absolute) polycythemias, relative (low plasma volume) polycythemias, high normal red cell mass (HNRCM) and 'physiological variant'. Absolute polycythemias were increasingly frequent at higher PCV levels but only reached 100% at a PCV of 0.60. They showed an 18% incidence in the lower PCV range of 0.500-0.519. Relative (low PV) polycythaemia was found in 18% of the patients with PCV values in the range 0.500 to 0.599. Although the HNRCM and 'physiological variant' types found mainly in the lower PCV ranges they occurred at the 0.54 level. While this method of interpretation of RCM and PV data is perhaps arbitrary, it does provide a basis for the proper study of the common group of patients with raised PCV levels in which classification, course and treatment are uncertain. In addition the findings suggest that both RCM and PV should be measured at all levels of PCV over 0.50; that relative (low PV) polycythaemia is a real entity but less common than sometimes believed; that diuretics do not have a notable part in its causation and that the common HNRCM, 'physiological variant' groups are incompletely understood and require further study.

Interpretation of measured red cell mass in the diagnosis of polycythaemia.

Expression of predicted and measured red cell mass (RCM) in terms of ml/kg body wt. lacks precision. The use of formulae for prediction of normal mean red cell mass derived from the blood volume prediction (BV) of Nadler et al (1962) has been examined. It is proposed that a more accurate determination of mean normal predicted red cell mass (MNRCM) is obtained by using: 0.47 X 0.91 X BV = MNRCM for males; 0.43 X 0.91 X BV = MNRCM for females. The MNRCMs given by these formulae agree with those given by predictions based on lean body mass and surface area. Examination of the '95% confidence limits' of the 'Nadler' prediction indicates that males with measured RCMs greater than 25% and females with measured RCMs greater than 30% above their MNRCM may be regarded as having polycythaemia.