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Background: Besides inducing behavioral unresponsiveness, a key goal of anesthesia is to prevent the experience of surgery (connected consciousness) by inducing either unconsciousness or disconnection of consciousness from the environment. In pursuing this key goal, avoiding the risk of postoperative cognitive dysfunction is also necessary. In this case report we relate electroencephalography waveform characteristics during intraoperative bispectral index monitoring to long-term neurocognitive decline. Case presentation: We describe the case of two 68-year-old homozygous twins who underwent the same general anaesthesia regimen, but had different results on neurocognitive testing 12 months postoperatively. Neurocognitive tests (Montreal Cognitive Assessment, Trail Making Test A and B, Digit Span Test, and Frontal Assessment Battery) were performed in three different times: the day before surgery, the third day postoperatively, and 12 months after surgery for follow-up. During anaesthesia, connected consciousness and anaesthesia depth were monitored using the isolated forearm technique and bispectral index monitoring. The mean value of bispectral index was lower in one twin (S1) than in the other (S2). Moreover, the same twin who presented lower values of bispectral index had two episodes of burst suppression, whereas the other had none. Regarding the neurocognitive evaluations, both twins did not show significative differences between the tests performed before and after surgery, but an important difference was founded at the 12-month follow-up, when only one twin (S1) showed distinctly worse test scores than previous, denoting a significant cognitive decline. Conclusions: This case-report suggests that bispectral index electroencephalography waveform characteristics during intraoperative bispectral index monitoring may be useful in detecting brain’s susceptibility to general anaesthesia and in predicting long-term neurocognitive decline.

Nucleic acid hybridization is extremely important in viral hepatitis research and the newly emerging techniques are now becoming an indispensable resource also in the diagnostic laboratory. This paper provides information on methods currently used for detection of viral nucleic acids with special emphasis on the importance of hepatitis B virus DNA in the serum. Herein, we describe the procedures for preparation and labeling of DNA probes and the principles that regulate dot, slot and Southern blot hybridization. Advantages and shortcomings of filter hybridization are discussed together with the alternative approaches to it. Finally, a collection of laboratory protocols is presented in Appendix #1.

Six patients with hepatitis B surface antigen (HBsAg)-positive chronic active liver disease and superimposed delta virus infection were followed up for changes of natural killer (NK) cell function during a 3-month course with median doses of recombinant leukocyte alpha interferon (rIFN). Careful record of the off-therapy NK function means revealed that 3 subjects were boosted, 2 were depressed, and 1 was unchanged. The NK activity patterns showed that after the start of therapy the maximal shift from the off-therapy mean was concentrated in the first week; then the trend, although confirmed, had a gentler slope on the follow-up. This indicated that the first week reflects the availability of rIFN-sensitive NK cells and characterizes the immunological competence of the patient; whilst later in follow-up, suppressive control mechanisms or loss of receptor affinity tend to blur the response. The serum levels of delta RNA dropped in the NK-boosted patients; persistently negative RNA together with clearance of intrahepatic delta antigen was demonstrated solely in that 1 patient showing 164% NK cell function increment in the first week. This study shows that paradoxical responses to exogenous rIFN are not confined to cancer patients, as indicated so far, but may appear in other subjects as well, and reflect the peculiar response of the individual; whenever an NK-dependent clearance of virus-infected cells is required, recognition of the early pattern of reactivity would be useful.(ABSTRACT TRUNCATED AT 250 WORDS)

Summary The expression of intrahepatic delta antigen (HDAg) was studied in relation to the morphologic features of HDV hepatitis and the outcome of liver disease. The study was performed in 101 patients followed up for an average of 12 years; one or more liver biopsies were available from each patient, giving a total of 167 specimens. The histologic features were assessed using numerical scores. A significant positive relation was observed between the number of HDAg-positive cells and the extent of portal inflammation (Spearman's rank coefficient 0.75). The highest degree of inflammation and intrahepatic expression of HDAg was found before the elimination of the virus, while the outcome of HDV disease was unrelated to the severity of the initial morphologic lesion. These results suggest that the individual immune response may play an important role in the pathogenesis of HDV hepatitis.

To the Editor. —Although interferon is being used in a growing number of human studies as a biological response modifier for therapy of malignancy and virus diseases of disparate kinds, the rationale of its use is still riddled with empiricism. Of the main actions of interferon, eg, induction of antiviral state, antineoplastic effect, and natural killer (NK) cell boosting capacity, the latter is well characterized in vitro, but its role in vivo does not seem clear from the results of therapeutic trials, and it has been stated that its changes do not correlate with the clinical results. 1 We describe herein a pilot study whereby severe liver disease due to the hepatitis B virus—dependent delta (HDV) agent 2 in six patients was treated with interferon as recombinant α-2 interferon (Schering-Plough) at 5 mega units per square meter of body surface, three times weekly for three months. All patients had biopsy