Michael Harvey

Hickman catheter complications in a haematology unit, 1996–98

Ninety-nine dual-lumen Hickman catheters were inserted in 77 patients (46 male and 31 female). A review of 96 catheters (44 male and 30 female patients) was conducted (Table 1).The most common diagnoses were: (i) acute myeloid leukaemia (in 33 patients), (ii) acute lymphoblastic leukaemia (in 18 patients) and (iii) non-Hodgkin’s lymphoma (in 18 patients). A further eight patients had other diagnoses. The preoperative full blood count showed: (i) a mean haemoglobin level of 112 g/L (median 110 g/L; range 77–153 g/L), (ii) a mean neutrophil count of 4.5 × 109/L (median 2.2 × 109/L; range 0–46 × 109/L), and (iii) a mean platelet count of 150 × 109/L (median 96 × 109/L; range 3–912 × 109/L).

Endobronchial deposits of chronic lymphocytic leukemia - an unusual cause of central airway obstruction.

A 66‐year‐old woman with a background of chronic lymphocytic leukemia (CLL) was admitted to the hospital on several occasions with recurrent episodes of community‐acquired pneumonia. Computed tomography and bronchoscopy revealed multiple obstructing endobronchial polyps. Post‐obstructive pneumonia together with immunoglobulin G deficiency was considered the most likely cause of these recurrent infections. Bronchoscopy was performed for removal of the critically obstructing lesions. Histopathology revealed replacement of bronchial mucosa with CLL deposits. Despite a brief window of infection‐free survival following therapy, she remained susceptible to pneumonia with further hospital admissions and eventually died from her disease.

Human Gγ and Aγ globin gene constructs containing the 3′ Aγ enhancer show persistent fetal expression in transgenic mice

Transgenic mice were produced from two 13 kb constructs containing the fetal (γ) globin genes. Each construct consisted of a Gγ globin gene linked to one of two alternative Aγ genes. The first construct contained a normal Gγ gene plus and Aγ gene with the −198T→C hereditary persistence of fetal haemoglobin (HPFH) mutation. In the second, a normal Gγ gene was linked to a Aγ gene with a−222 to −225 four base pair deletion in the promoter. This latter mutation has been associated with low Aγ expression in humans. Both Aγ genes in these constructs also contained the 3′ flanking enhancer. The two different constructs showed expression throughout gestation from day 11 yolk sac, through the fetal period and for a variable time during the first three postnatal weeks. Thereafter, no expression of any of the γ-globin genes was seen in adult erythroid tissues. Transcription from the normal Gγ and HPFH Aγ genes in the first construct paralleled each other in developmental timing, with a proportionate excess of Aγ more evident in later gestation. Gγ and Aγ mRNA transcripts from the normal Gγ+4 bp deletional Aγ construct were unable to be distinguished because of a 3′ Gγ-like conversion in the deletional Aγ gene. Combined γ-globin expression from the two genes in this second construct was detectable until just after birth, as seen with the individual genes in the first construct. Previous work has shown that when individual Gγ and Aγ transgenes are introduced into mice unlinked, without the locus control region (LCR), embryonic expression only is seen. In the present study, γ-globin expression was evident from both constructs throughout the fetal period of erythropoiesis. This suggests that the additional DNA sequences flanking the γ-globin genes included in these larger constructs are capable of supporting fetal recruitment of the γ-globin genes, independently of the LCR.