Respiratory muscle function in cystic fibrosis.

Maximal static expiratory and inspiratory mouth pressures (PEmax and PImax) and quadriceps femoris muscle strength were measured in 25 patients aged 16-28 years with cystic fibrosis (mean FEV1 46% predicted). Mean (SD) PEmax was 64% (18%) predicted (below 75% predicted in 16 of the 25 patients), and PImax was 64% (24%) predicted (below 75% predicted in 14 patients). Quadriceps muscle strength was 68% (20%) predicted (below 75% predicted in 17 patients). The relatively small reduction in respiratory muscle strength in these patients was unlikely to have contributed appreciably to their respiratory problems.     

Acute promyelocytic leukemia following treatment of non-Hodgkin's lymphoma

A case of acute promyelocytic leukemia (APL) 3 years following the treatment of diffuse mixed non-Hodgkin's lymphoma (NHL) is presented. This is the second time APL after NHL has been reported in the literature.     

Bilateral ischemic optic neuropathy and retinal vascular occlusions associated with lymphoma and sepsis. Clinicopathologic correlation

The authors report the clinicopathologic correlation of a patient with non-Hodgkin's mixed-cell lymphoma who had impairment of the circulation of the optic nerve and retina in both eyes. The results of histopathologic examination showed that the pial septa of the optic nerves were infiltrated by lymphoma and that there was extensive infarction of the orbital portions of both optic nerves and occlusion of both central retinal arteries and the right central retinal vein by thrombi with bacteria. The infiltration of the optic nerves seemed to be resistant to therapy.     

Environmental and genetic determinants of the hypercoagulable state and cardiovascular disease in renal transplant recipients

Background. Fibrinogen and factor VII coagulant activity (VIIc), risk factors for cardiovascular disease (CVD) in the general population, could contribute to CVD risk in renal transplant recipients (RTR). Methods. We measured fibrinogen and VIIc in 38 RTR and 31 controls, along with prothrombin fragment F1+2 and D-Dimer (markers of coagulation and fibrinolytic activation), plasma lipids and the acute phase response cytokine, interleukin 6. The effect of genetic polymorphisms of {beta}-fibrinogen (G/A^-455) and factor VII (Arg/Gln353) was explored. Results. F1+2, D-Dimer, and fibrinogen were increased in all RTR, indicating a chronic prothrombotic state. Fibrinogen correlated with age, F1+2, and trough cyclosporin A (CsA). RTR carriers of the A^-455 allele had a greater increment in plasma fibrinogen concentration and correlation with CsA than homozygotes for the G^-455 allele. Interleukin 6 was increased in RTR confirming that a persistent low-grade acute-phase response could contribute to increased fibrinogen. Differences in plasma VIIc were associated with factor VII genotype, disease status, and blood lipids. Carriers of the Gln353 allele had 30 lower VIIc when compared with Arg353 homozygotes, which could confer a reduced thrombotic risk. The 12 RTR with CVD or metabolic complications (RTR+) were more hyperlipidaemic and had higher fibrinogen and VIIc than the 26 RTR free of disease complications (RTR-), or the controls. Conclusions. Long-term RTR manifest features of a chronic prothrombotic and persistent inflammatory state. Alterations in fibrinogen and VIIc in RTR arise in part as a result of interactions between common genetic and environmental factors, and these changes could contribute to the increased risk of CVD in RTR.     

Immunology

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in immunology.     

Starch, gloves and extradural catheters

We have investigated contamination of extradural catheters during normal handling with starch powdered gloves. In the laboratory, extradural catheters were handled in sterile fields with both powdered and non-powdered gloves, simulating preparation for patient insertion. The catheters together with glove samples were then examined using a Zeiss 940 scanning electron microscope. Microscopy of samples revealed starch contamination of the catheters handled with powdered gloves, especially in the side hole areas. We conclude that extradural catheters may be contaminated easily by starch powder from surgical gloves. This powder may then be deposited into the extradural space. The effect of starch in the extradural space is not known but starch is known to cause inflammatory and granulomatous reactions in other parts of the body as well as being directly allergenic. Powder contamination of catheters may be avoided easily by the use of powder-free gloves and we feel that these should be used whenever possible.      

Absence of insulin receptor gene mutations in three insulin-resistant women with the polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) are markedly insulin-resistant, but the molecular mechanisms of these changes and their relationship to the hyperandrogenic state remain to be clarified. Mutations have recently been identified in the insulin receptor gene of patients with extreme forms of insulin resistance associated with hyperandrogenism (eg, type A insulin resistance), and these mutations account for the insulin resistance in such patients. We performed this study to determine whether mutations in the coding portion of the insulin receptor gene were responsible for insulin resistance in PCOS. Insulin binding studies using cultured skin fibroblasts of three obese (body mass index > 27 kg/m²) women with PCOS (ie, mild hyperandrogenemia and chronic anovulation of unknown etiology) and documented insulin resistance showed no apprarent abnormalities in either the number or affinity of insulin binding sites. Direct sequencing of all 22 exons of the insulin receptor gene from two of the women with PCOS did not reveal any mutations. Furthermore, both alleles of the gene were expressed at equal levels. In a third insulin-resistant PCOS woman, there was no evidence for a mutation in the coding portion of the insulin receptor gene as determined by denaturing gradient gel electrophoresis (DGGE). We conclude that the insulin resistance in these PCOS women was caused by a defect extrinsic to the insulin receptor.