ISCHAEMIA-REPERFUSION INJURY TO THE INTESTINE

Ischaemia-reperfusion injury (IRI) is of obvious relevance in situations where there is an interruption of blood supply to the gut, as in vascular surgery, or in the construction of free intestinal grafts. It is now appreciated that IRI also underlies the gut dysfunction that occurs in early shock, sepsis, and trauma. The events that occur during IRI are complex. However, recent advances in cellular biology have started to unravel these underlying processes. The aim of this review is to provide an outline of current knowledge on the mechanisms and consequences of IRI. Initially, IRI appears to be mediated by reactive oxygen metabolites and, at a later stage, by the priming and activation of polymorphonuclear neutrophils (PMN). Ischaemia-reperfusion injury can diminish the barrier function of the gut, and can promote an increase in the leakage of molecules (intestinal permeability) or the passage of microbes across the wall of the bowel (bacterial trans-location). Ischaemia-reperfusion injury to the gut can result in the generation of molecules that may also harm distant tissues.     

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.      

Pulmonary artery rupture in pregnancy complicating patent ductus arteriosus.

Fatal haemopericardium in a 27 year old pregnant woman was caused by rupture of a dissecting aneurysm of the pulmonary artery. She had an uncorrected patent ductus arteriosus and severe pulmonary hypertension. The wall of the pulmonary artery showed atherosclerosis and cystic medionecrosis.     

Sexually transmitted disease, ethnomedicine and health policy in Africa.

Compared with both industrialized countries and other less developed parts of the world, most of sub-Saharan Africa suffers inordinately from sexually transmitted diseases (STDs). It has high prevalence rates of traditional STDs, such as gonorrhea and syphilis, and if accurate seroprevalence surveys were to be done, it would probably prove to have the highest HIV seropositive incidence in the world. Unlike the pattern in the West, AIDS is primarily a heterosexually transmitted disease in Africa. This appears to be largely because of the prevalence of other untreated or improperly treated STDs. Therefore to lower the incidence of STDs would be to curtail the spread of HIV infection. The problem becomes how exactly to accomplish this. Most STD cases are never even presented at biomedical health facilities; they are presented to traditional healers. Both healers and their patients seem to believe that traditional STD cures are more effective than 'modern' cures, although the former are probably biomedically ineffective. While there is scant ethnomedical literature on STDs in Africa, the present paper presents Swaziland findings and related evidence from other African societies that the ultimate cause of several common STDs is believed to be the violation of norms governing sexual behavior, requiring traditional rather than biomedical treatment. Traditional healers therefore need to be a central part of any scheme to lower the incidence of STDs.