Diarrhoea-causing microorganisms are rare in adult patients undergoing diagnostic laparoscopy for suspected appendicitis: a prospective observational cohort study

AIM

We investigated if diarrhoea-causing bacteria, including Yersinia species, could mimic the symptoms of appendicitis and lead to surgery.

METHODS

This prospective observational cohort study included adult patients undergoing surgery for suspected appendicitis. Rectal swabs were analysed with polymerase chain reaction (PCR) for Yersinia, Campylobacter, Salmonella, Shigella, and Aeromonas spp. Blood samples were analysed routinely and with an in-house ELISA serological test for Yersinia enterocolitica antibodies. We compared patients without appendicitis and patients with appendicitis confirmed by histopathology. The outcomes included PCR-confirmed infection with Yersinia spp., serologic-confirmed infection with Y. enterocolitica, PCR-confirmed infection with other diarrhoea-causing bacteria, and Enterobius vermicularis confirmed by histopathology.

RESULTS

A total of 224 patients were included, 51 without and 173 with appendicitis, and followed for 10 days. PCR-confirmed infection with Yersinia spp. was found in one patient (2%) without appendicitis and no patients (0%) with appendicitis (p=0.23). Serology was positive for Yersinia enterocolitica for the same patient without appendicitis and two patients with appendicitis (p=0.54). Campylobacter spp. were detected in 4% vs. 1% (p=0.13) of patients without and with appendicitis, respectively.

CONCLUSIONS

Infection with Yersinia spp. and other diarrhoea-causing microorganisms in adult patients undergoing surgery for suspected appendicitis was rare.

Mesenteric Lymphadenitis and Terminal Ileitis is Associated With Yersinia Infection: A Meta-analysis

BACKGROUND

Yersinia infection affects terminal ileum and lymph nodes and could therefore mimic the symptoms of appendicitis. We aimed to systematically characterise the suspected or confirmed abdominal diseases and/or surgeries associated with Yersinia infection.

MATERIALS AND METHODS

This systematic review and meta-analysis was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A protocol (CRD42016053252) was uploaded to PROSPERO. The searches were conducted in PubMed and EMBASE on October 2, 2020. Original reports on patients with abdominal surgical diseases were included. The primary outcome was to characterise suspected or confirmed abdominal surgical diseases and/or surgeries associated with Yersinia infection, while the secondary outcomes were the positive rate of Yersinia species for each disease and surgery, and to investigate the rate of Yersinia spp. in different geographic regions. We calculated the weighted mean prevalence of positive tests for Yersinia spp. for the different diseases and surgeries according to the detection method and for subgroups based on geographic region.

RESULTS

From the search, 33 studies were included in the systematic review and 18 in the meta-analysis. Across geographic regions, the weighted mean prevalence for Yersinia spp. was 51% (95% CI 34%-69%) in mesenteric lymphadenitis, 65% (95% CI 45%-85%) in terminal ileitis, and 8% (95% CI 2%-15%) in normal appendices.

CONCLUSIONS

Around half of the patients with mesenteric lymphadenitis and terminal ileitis were serologically positive for infections with Yersinia spp. Yersinia infection may cause unnecessary surgery for suspected appendicitis due to symptoms from mesenteric lymphadenitis or terminal ileitis.

Patient-reported health and 1-year mortality in patients with ischemic heart disease – findings from the Denheart study

Background

Though survival has improved markedly in ischemic heart disease (IHD), it remains a leading cause of death worldwide. Screening tools to identify patients at risk are ever in demand. Large-scale studies exploring the association between patients' self-reported mental and physical health and mortality are lacking.

Purpose

(i) to describe patient-reported outcomes (PROs) at discharge in IHD patients deceased and alive at one year, (ii) to investigate the discriminant predictive performance of PRO instruments on mortality, (iii) to investigate differences in time to death among survey responders/non-responders and among three diagnostic sub-groups (chronic ischemic heart disease/stable angina, non-STEMI/unstable angina and STEMI), and (iv) to investigate predictors of one-year mortality among sociodemographic, clinical and self-reported factors.

Methods

Data from the national DenHeart survey with register-data linkage was used. A total of 14,115 adults with IHD were discharged during one year. Eligible (n=13,476) were invited to complete a questionnaire and 7,167 (53%) responded. Questionnaires included the Health survey short form 12-items (SF-12), Hospital Anxiety and Depression Scale (HADS), EuroQoL-5-dimensions (EQ-5D), HeartQoL, Edmonton Symptom Assessment Scale (ESAS) and ancillary questions. Clinical and demographic characteristics were obtained from registries as were data on one-year mortality. Comparative analyses investigated differences in PROs, and discriminant PRO-performance was explored by Receiver Operating Characteristics (ROC) curves. Kaplan-Meier survival analysis explored differences in time to death across sub-groups. Predictors of mortality were explored using multifactorially adjusted cox regression analyses with time to death as underlying timescale.

Results

Highly significant and clinically important differences in PROs were found between those alive and those deceased at one year. The best discriminant performance was observed for the physical component scale of the SF-12 (Area Under the Curve (AUC) 0.706) (Figure 1). One-year mortality among responders and non-responders was 2% and 7%, respectively. Significant differences in time to death was observed between responders and non-responders (p<0.001) and among diagnostic subgroups (p<0.001). Strongest predictors of one-year mortality included STEMI (hazard ratio (HR) 2.9 95% confidence interval (CI) 2.3–3.7), Tu comorbidity index score 3+ (HR 3.6, 95% CI 2.7–4.8) and patient-reported feeling unsafe about returning home from hospital (HR 2.07, 95% CI 1.2–3.61).

Conclusions

One-year post-discharge mortality was expectedly low, however notably higher in certain subgroups. Though clinical predictors may be difficult to modify, factors such as feeling unsafe about returning home should be addressed at discharge. PRO-performance estimates may guide clinicians and researchers in choosing appropriate predictive patient-reported outcome tools.

Figure 1. PRO instruments ROC curves

Funding Acknowledgement

Type of funding source: None

Shorter Total Length of Stay After Intraperitoneal Fosfomycin, Metronidazole, and Molgramostim for Complicated Appendicitis: A Pivotal Quasi-Randomized Controlled Trial

Background: We aimed to investigate the difference in the total length of hospital stay (LOS) after intraperitoneal vs. intravenous antibiotic treatment in patients with complicated appendicitis.

Methods: We conducted a quasi-randomized prospective clinical trial. The intervention group received 4 g fosfomycin, 1 g metronidazole, and 50 μg recombinant human granulocyte-macrophage colony-stimulating factor intraperitoneally, which was left in the abdominal cavity, immediately after laparoscopic appendectomy. Postoperatively, this group received antibiotics orally. The control group received intravenous antibiotics both during surgery and postoperatively. We primarily evaluated total LOS within 30 days. Furthermore, we evaluated harms and adverse events, Gastrointestinal Quality of Life Index, postoperative complications, and convalescence. Participants were followed for 30 days postoperatively.

Results: A total of 12 participants concluded the trial. The total LOS was significantly shorter in the intervention group (six participants, median 13 h; range 2–21 h) than in the control group (six participants, median 84 h; range 67–169 h), p = 0.017. Comparable harms and Gastrointestinal Quality of Life Index scores were found in the two groups. The time to return to normal activities was median 6 and 10 days for the intervention and the control group, respectively. There were no serious adverse events related to the trial nor any complications in the intervention group. In the control group, two patients developed intraabdominal abscesses.

Conclusions: The intervention group had a significantly shorter total LOS. The study was not powered to assess differences in complications, but the results indicate that the intervention seems to be a safe regimen, which can be investigated further to treat patients with complicated appendicitis.

Identifiers: EudraCT no. 2017-004753-16.

ClinicalTrials:https://clinicaltrials.gov/ct2/show/NCT03435900?term=NCT03435900&draw=2&rank=1">draw=2&rank=1.

P612Multimodal cardiac imaging in patients with suspected ST-elevation myocardial infarction and no obstructive coronary arteries

Background

Patients with suspected ST-elevation myocardial infarction (STEMI) and normal coronary arteries comprise a heterogeneous group with various underlying causes of disease.

Purpose

To study pathophysiology and underlying diagnoses in patients with suspected STEMI and normal coronary arteries using multimodal cardiac imaging.

Methods

We consecutively included patients with suspected STEMI, normal coronary arteries on acute coronary angiography, and elevated troponin T levels at a tertiary heart center (2012–14). Patients were examined with echocardiography, cardiac magnetic resonance imaging, and 13NH3/82Rb and 18F-FDG positron emission tomography within one week from symptom onset.

Results

We included 42 patients (60% male, median age 58 (IQR 50–65) years. Median troponin T levels were 783 (IQR 566–1208) ng/l. Multimodal cardiac imaging findings are presented in Table 1. Multimodal cardiac imaging showed signs of cardiac involvement in all but one patient (98%). Underlying diagnoses were acute myocardial infarction (36%), Takotsubo cardiomyopathy (29%), perimyocarditis (10%), and cardiomyopathy (7%). The diagnosis was unclear in 19% of patients.

Echocardiography   Left ventricular ejection fraction <40%, n (%) 12 (29)   Moderate to severe left ventricular hypertrophy, n (%) 3 (7)   Moderate to severe valvular disease, n (%) 3 (7)   Pericardial effusion, n (%) 5 (12)   Apical thrombus, n (%) 1 (2) Magnetic resonance imaging   Left ventricular end diastolic volume, ml (IQR) 157 (125–185)   Left ventricular end systolic volume, ml (IQR) 75 (63–88)   Left ventricular stroke volume, ml (IQR) 73 (57–93)   Edema, n (%) 38 (91)   Late gadolinium enhancement, n (%) 22 (52) 13NH3/82Rb and 18F-FDG positron emission computer tomography   Myocardial perfusion defect, n (%) 29 (69)   Myocardial perfusion-metabolism mismatch, n (%) 12/30 (40)   Reduced myocardial viability, n (%) 6/30 (20)

Conclusion

The majority of patients with suspected STEMI and normal coronary arteries had signs of cardiac involvement by multimodal cardiac imaging and were diagnosed with cardiac disease.

Acknowledgement/Funding

The Danish Heart Foundation, the A.P. Møller Foundation, the Foundation of Reinholdt W. Jorck and Wife, Rigshospitalet's Research Foundation

[A low risk of ileus, incisional hernia and impact on female fertility after appendectomy]

Appendicitis is a common condition, which is often seen by the general practitioners as well as in the emergency departments. It is normally treated with laparoscopic appendectomy. This review gives an overview of the long-term surgical complications ileus and incisional hernia and of the impact of appendicitis and appendectomy on female fertility. The literature shows, that there is a low risk of ileus and incisional hernia after appendectomy, and that there is no change in female fertility after appendectomy, not even in cases where the appendix was perforated.

Long-Term Complications of Appendectomy: A Systematic Review

BACKGROUND AND AIMS

Appendectomy is a common surgical procedure, but no overview of the long-term consequences exists. Our aim was to systematically review the long-term complications of appendectomy for acute appendicitis.

MATERIALS AND METHODS

This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A protocol was registered on PROSPERO (CRD42017064662). The databases PubMed and EMBASE were searched for original reports on appendectomy with n ≥ 500 and follow-up >30 days. The surgical outcomes were ileus and incisional hernia; other outcomes were inflammatory bowel disease, cancer, fertility, and mortality.

RESULTS

We included 37 studies. The pooled estimate of the ileus prevalence was 1.0% over a follow-up period of 4.6 (range, 0.5-15) years. Regarding incisional hernia, we found a pooled estimate of 0.7% prevalence within a follow-up period of 6.5 (range, 1.9-10) years. Ulcerative colitis had a pooled estimate of 0.15% prevalence in the appendectomy group and 0.19% in controls. The opposite pattern was found regarding Crohn's disease with a pooled estimate of 0.20% prevalence in the appendectomy group and 0.12% in controls. No clear pattern was found regarding most of the examined cancers in appendectomy groups compared with background populations. Pregnancy rates increased after appendicitis compared with controls in most studies. Mortality was low after appendectomy.

CONCLUSION

Appendectomy had a low prevalence of long-term surgical complications. We did not find any significant other long-term complications, though the prevalence of Crohn's disease was higher and the prevalence of ulcerative colitis was lower after appendectomy than in controls. Appendectomy did not impair fertility.

Osteoclast nuclei of myeloma patients show chromosome translocations specific for the myeloma cell clone: a new type of cancer-host partnership?

A major clinical manifestation of bone cancers is bone destruction. It is widely accepted that this destruction is not caused by the malignant cells themselves, but by osteoclasts, multinucleated cells of monocytic origin that are considered to be the only cells able to degrade bone. The present study demonstrates that bone-resorbing osteoclasts from myeloma patients contain nuclei with translocated chromosomes of myeloma B-cell clone origin, in addition to nuclei without these translocations, by using combined FISH and immunohistochemistry on bone sections. These nuclei of malignant origin are transcriptionally active and appear fully integrated amongst the other nuclei. The contribution of malignant nuclei to the osteoclast population analysed in this study was greater than 30%. Osteoclast-myeloma clone hybrids contained more nuclei than normal osteoclasts and their occurrence correlated with the proximity of myeloma cells. Similar hybrid cells were generated in myeloma cell-osteoclast co-cultures, as revealed by tracing myeloma nuclei using translocations, bromo-deoxyuridine, or the Y chromosome of male myeloma cells in female osteoclasts. These observations indicate that hybrid cells can originate through fusion between myeloma cells and osteoclasts. In conclusion, malignant cells contribute significantly to the formation of bone-resorbing osteoclasts in multiple myeloma. Osteoclast-myeloma clone hybrids reflect a previously unrecognized mechanism of bone destruction in which malignant cells participate directly. The possibility that malignant cells corrupt host cells by the transfer of malignant DNA may have been underestimated to date in cancer research.

Toll-like receptors mediate proliferation and survival of multiple myeloma cells

Multiple myeloma (MM) is an incurable B-cell malignancy characterized by accumulation of malignant plasma cells in bone marrow (BM) and recurrent or persistent infections. Toll-like receptors (TLRs) are essential in the host defense against infections and today 10 human TLRs (TLR1-TLR10) and one TLR-homolog (RP105) have been characterized. B cells express several TLRs (mainly TLR1, 6, 7, 9, 10 and RP105) and TLR-initiated responses in B cells include proliferation, anti-apoptosis effect and plasma cell (PC) differentiation. The present study was designed to analyze the role of TLRs in MM. We show that frequent expressions of TLRs were detected in cell lines from MM patients (minimum six TLRs in each). In comparison, only few TLRs (mainly TLR1 and or RP105) were found expressed in PCs from BM of healthy donors. In addition, TLR-specific ligands induce increased proliferation and survival of the MM cell lines, partially due to an autocrine interleukin-6 production. Importantly, we demonstrate that also PC from MM patients proliferates in response to TLR-specific ligands. In conclusion, TLR-ligands may contribute to increased growth and survival of MM cells in MM patients.

Longitudinal observation of enterovirus and adenovirus in stool samples from Norwegian infants with the highest genetic risk of type 1 diabetes

BACKGROUND

Enterovirus and adenovirus are common in infancy, causing mostly asymptomatic infections. However, even an asymptomatic infection may be associated with increased risk of development of certain chronic non-infectious diseases, as has been suggested for enterovirus and type 1 diabetes. Data on occurrence and course of the infections in infancy are therefore important for designing effective approaches towards study of the association.

OBJECTIVES

To estimate the frequency of enterovirus and adenovirus infections in Norwegian infants, to evaluate the duration of the infections, to investigate their association with symptoms, and to establish a robust procedure that will be used to study the association between these viruses and the development of auto-immunity leading to type 1 diabetes.

STUDY DESIGN

Parents of infants, recruited for a study on environmental triggers of type 1 diabetes, submitted monthly samples of infant faeces, as well as information on symptoms of infection. The samples were analysed for enterovirus and adenovirus using quantitative real-time PCR, and enterovirus-positive samples were sequenced.

RESULTS

Enteroviruses were found in 142/1,255 (11.3%), and adenoviruses in 138/1,255 (11.0%) of stool samples. Approximately half of the infants were exposed to these viruses at least once during the first year of observation (period 3-14 months of age). The presence of adenovirus was associated with fever and with symptoms of cold but not with diarrhoea and vomiting. The enterovirus positivity was not associated with any symptoms.

CONCLUSIONS

The prevalence of enterovirus and adenovirus in longitudinally obtained faecal samples from infants is sufficiently high to enable studies of their association with chronic diseases. The present protocol for evaluating exposure to these viruses is well suited for large-scale efforts aimed at assessing possible long-term consequences, particularly in relation to type 1 diabetes.

250 DISTRIBUTION OF HISTONE macroH2A1 IN BOVINE PRE-IMPLANTATION EMBRYOS DERIVED FROM PARTHENOGENETIC ACTIVATION AND IN VITRO FERTILIZATION

It is known that heterochromatin is characterized by the presence of the histone variant of macroH2A1. MacroH2A1 is a core variant histone with a hybrid structure consisting of a domain that resembles a full-length histone H2A1 followed by a large nonhistone domain. We have previously studied the dynamic changes of macroH2A1 accumulation during the pre-implantation developmental period in the mouse. In the present study, we investigated the distribution of microH2A1 in bovine metaphase II oocytes and pre-implantation embryos at 2-, 4-, 8-, 16-cell, and morula stages as well as blastocysts harvested at Days 8, 9, 10, 11, 12, and 13 following activation and in vitro fertilization (IVF). To generate parthenotes, denuded and in vitro-matured oocytes were activated using a combined treatment of calcium ionophore A23187, cycloheximide (CHX), and 6-dimethylaminopurine (6-DMAP). Five oocytes and pre-implantation embryos at each stage of development were used to follow the development expression pattern of microH2A1 by immunocytochemistry. The cross-reactivity of the primary antibody against mouse microH2A1 was verified by Western blot analysis with bovine fibroblasts. Another staining control included immunostaining with antibody against histone molecules. The stained embryos were observed by laser-scanning confocal microscopy and epiflourescence microscopy. No microH2A1 stain was observed in bovine oocytes or pre-implantation embryos up to the expanded blastocyst stages. In the IVF group, the macroH2A1 was first found in elongated blastocysts (Day 11) after hatching. We observed different expression patterns of macroH2A1 in activated vs. IVF bovine embryos. In the parthenote group, we failed to find robust expression even when embryos were cultured for 13 days. Moreover, the pattern of macroH2A1 expression in bovine embryos was different fromn that in the mouse, in which the onset of macroH2A1 expression occurred by the 16-cell morula stage. These results suggest species differences in the establishment of epigenetic signals. This work was supported by grants from USDA to X. Y. and X. C. T.

Quality assessment of autografting by probability evaluation: model estimation by clinical end-points in newly diagnosed multiple myeloma patients

BACKGROUND

Pre-transplant clinical evaluation of autografting is an important step in predicting post-transplant support, complications and safety. Today, unfavorable outcomes such as early death or graft failure are rare, making them unsuitable for quality assessment of supportive autografting. However, end-points constructed from frequently occurring clinical events may estimate clinically relevant prognostic models.

METHODS

The present retrospective analysis was based on two consecutive clinical trials in the Nordic area including up to 640 newly diagnosed multiple myeloma patients.

RESULTS

In the model, the efficacy (time on antibiotics and use of transfusions) was influenced by pre-transplant variables, including sex, nationality, serum creatinine, hemoglobin, disease stage at diagnosis, response following induction therapy, length of priming and average graft CD34+ cell number per day of harvest. The toxicity end-point (time to blood cell recovery) was influenced by nationality, marrow plasma cell percentage, serum creatinine, M-component isotype, response to induction therapy, length of priming and graft CD34+ cell number. The safety (early disease recurrence or death) was influenced by serum creatinine, hemoglobin, treatment response and CD34+ cell number.

DISCUSSION

In conclusion, the model illustrates that intervention strategies in quality assessment of autografting may benefit from probability estimates of graded clinical end-points.

Changes in hemorheological and biochemical parameters following short-term and long-term smoking cessation induced by nicotine replacement therapy (NRT)

OBJECTIVES

Cigarette smoking causes cardiovascular (CV) disease, but the relative roles of nicotine and other components of tobacco smoke remain unclear. We investigated the effect of stopping smoking by using nicotine replacement therapy (NRT) on hemorheology parameters, on the cotinine and thiocyanate plasma concentrations and the exhaled carbon monoxide (CO).

DESIGN

Open, parallel-group trial (intervention group and control smokers).

SUBJECTS

197 males, aged 25-45 years, smoking > 20 cigarettes per day (cpd).

INTERVENTIONS

164 subjects were instructed to stop smoking and received NRT for 12 weeks and 33 acted as controls. After 12 weeks, NRT was discontinued and all subjects were followed-up at 26 weeks. Beginning with week 4, the treated subjects were divided into abstainers (self-reported, verified by exhaled CO < 10 ppm) and nonabstainers, not able to stay abstinent since baseline. The group of the nonabstainers was stratified in 2 subgroups, the reducers (smoked < 50% of baseline number of cpd) and relapsers (smoked 50-100% of baseline cpd).

MAIN OUTCOME MEASURES

Plasma viscosity, erythrocyte deformability, fibrinogen, transcutaneous partial oxygen tension (tcpO2), hematocrit, white blood cells, cotinine and thiocyanate plasma concentrations and exhaled CO, all assessed at 4, 8, 12 and 26 weeks.

RESULTS

After 6 months, plasma fibrinogen (228.2 vs. 275.4 mg/dl at baseline, p < 0.001), tcpO2 (50.4 vs. 34.9 mm mercury at baseline, p < 0.0001) were significantly improved in abstainers, but changes in plasma viscosity and erythrocyte deformability were inconclusive. Cotinine and thiocyanate (abstainers: 6.2 ng/ml at week 26 vs. 10.4 ng/ml at baseline, p < 0.0001) and expired CO (abstainers: 30.4 vs. 4.2 ppm, control vs. week 26, p < 0.0001) accurately followed the changes in smoking and/or NRT use in all of the groups. Other CV risk factors such as hematocrit and white blood cell count decreased to a greater extent in abstainers than in reducers and relapsers. Not only abstainers but also reducers did benefit of the temporarily stop smoking.

CONCLUSIONS

Smoking cessation improved CV parameters despite the measured cotinine and thiocyanate plasma levels, and use of nicotine medications did not negate these improvements. A smoking cessation for a short time and smoking of reduced cpd also improved these parameters temporarily.

Impaired learning correlates with size of excitotoxic hippocampal CA3 lesions in adult rats, but shows no amelioration by CA3 transplants

Hippocampal CA3 pyramidal cells grafted as cell suspensions to excitotoxic hippocampal lesions in adult rats can exchange several types of short and long range nerve connections with the host brain. We now examined whether such grafts also had functional effects in terms of ameliorating lesion-induced learning and memory deficits. Adult, male rats with bilateral, one week old, ibotenic acid-lesions of the hippocampal CA3 region, were grafted with suspensions of fetal (E18-19) CA3 cells. Seven weeks later the animals were tested for spatial navigation in the Morris Watermaze, together with groups of lesion-only and sham-operated, control rats. The tests were performed over 5 days, with 4 trials per day. At the end of the trials, the size of the lesions and the size and structural incorporation of the transplants in the host brains were evaluated morphometrically for correlations with the behavioural data. We found significant differences in swim pathlength and latency to find the platform in the Morris Watermaze between the lesion-only group and the grafted group versus the sham operated group, but no significant difference between the lesion-only and the grafted group. There was a significant positive correlation between the size of the CA3 lesions and the paucity of performance of the rat in the Watermaze, just as spontaneous recovery accordingly had not occurred over the 8 weeks postlesion. We conclude that the behavioural improvement exerted by the CA3 cell suspension grafts, at a time point when graft-host connections have had time to establish, is at most incomplete by these transplants, pointing to the difficulties there may be in obtaining full functional integration.

Effects of cigarette smoking or nicotine replacement on cardiovascular risk factors and parameters of haemorheology

OBJECTIVES

Cigarette smoking causes cardiovascular (CV) disease, but the relative roles of nicotine and other components of tobacco smoke remain unclear. We investigated the effect of stopping smoking, by using nicotine replacement therapy (NRT), on haemorheology parameters.

DESIGN

Open, parallel-group trial (intervention group and control smokers).

SETTING

Clinic within university department of pharmacology.

SUBJECTS

One hundred and ninety-seven males, aged 25-45 years, smoking >20 cigarettes per day.

INTERVENTIONS

One hundred and sixty-four subjects were instructed to stop smoking and received NRT for 12 weeks and 33 acted as controls. After 12 weeks, NRT was discontinued, and all subjects were followed-up at 26 weeks. At the end of the study, the NRT group was divided into abstainers (self-reported, verified by exhaled carbon monoxide <10 ppm) and relapsers, who were unable to remain abstinent.

MAIN OUTCOME MEASURES

Plasma viscosity, fibrinogen, erythrocyte deformability, reactive capillary blood flow, transcutaneous partial oxygen tension (tcpO2) and haematocrit, assessed at 4, 8, 12, and 26 weeks. Results. After 6 months, plasma fibrinogen (9.95 vs. 8.24 micromol x L(-1) at baseline; P < 0.003), reactive capillary flow (t-pmax: 9.3 vs. 11.2 s at baseline; P < 0.005), and tcpO2 (50.4 vs. 34.9 mmHg at baseline; P < 0.0001) were significantly improved in abstainers, but changes in plasma viscosity and erythrocyte deformability were inconclusive. Other CV risk factors, such as haematocrit and white blood cell count, decreased to a greater extent in abstainers than in relapsers. Expired carbon monoxide concentrations reflected the changes in smoking and decreased in abstainers from 30.4 ppm at baseline to 4.2 ppm; P < 0.0001). Conclusions. Smoking cessation improved CV parameters, and use of nicotine medications did not negate these improvements.

Atomic force microscopy study of the interaction of Fusarium solani pisi cutinase with lipid surfaces

We present an atomic force microscopy (AFM) study of a supported triacylglyceride multilayer phase and its interaction with lipolytic enzyme cutinase from Fusarium solani pisi. The multilayer triacylglyceride phase of coconut oil showed a rippled surface structure in the AFM images. Upon enzymatic degradation of the triacylglyceride phase, the ripple structure vanished rapidly. The apparent catalytic rate constants could be estimated based on the AFM image information. Interestingly, in one sample we observed what we interpret as a recurrent structural collapse of the cavity dug out by the protein. We interpret the cavities seen in the AFM images as molten surfaces or surface holes filled with liquidified phase containing product molecules, which appear transparent during the image recording.

The presence of circulating clonal CD19+ cells in multiple myeloma

Multiple myeloma (MM) is a B-cell malignancy characterized by the expansion of mature plasma cells (PC) localized in the bone marrow (BM). Several studies have identified circulating clonotypic CD19+ cells at a differentiation stage preceding the PC. The level of circulating clonotypic CD19+ cells is highly variable but generally low. Circulating clonotypic cells respond well to induction therapy, although a small subset within the CD19 compartment is resistant even to high-dose chemotherapy. The clonal CD19+ cells represent an ongoing differentiating population ranging from memory B-cells to plasmablasts. However, a clonal relationship gives no proof of malignant potential, and whether or not clonotypic precursor cells are involved in the disease process is a subject of intense debate. Translocations involving the immunoglobulin locus (14q32) are an early non-transforming event common to both monoclonal gammopathy of undetermined significance (MGUS) and MM introduced at the memory B-cell level. At the plasmablast stage, a phenotypic transformation occurs with downregulation of CD19 and upregulation of myeloma specific markers such as CD56, CD117 and CD28. Translocations involving the isotype-switch machinery and the introduction of tumor-specific markers at the plasmablast stage suggest that the clonal CD19+ memory B-cells and CD19+ plasmablasts are non-malignant, but immortalized relatives that gave rise to myeloma. A final proof of the malignant potential of CD19+ clonotypic cells might await the identification of the molecular events causing the transformation in myeloma.

Frequency and prognostic relevance of cyclin D1 dysregulation in multiple myeloma

OBJECTIVE

Cyclin D1 dysregulation has been found with varying frequencies in multiple myeloma (MM) and has been suggested to be associated with a poor prognosis. The aim of this study was to investigate the frequency of cyclin D1 dysregulation in patients being treated for MM and to test whether cyclin D1 dysregulation is a prognostic factor for MM patients.

METHODS

To achieve the above aims we designed a highly sensitive and reproducible real-time reverse-transcription polymerase chain reaction (RT-PCR) assay for quantitation of cyclin D1 mRNA. Using this assay, 110 diagnostic bone marrow (BM) samples from patients with MM were screened for cyclin D1 dysfunction.

RESULTS

The real-time assay was able to detect the presence of 0.01% cyclin D1 positive cells allowing a safe detection in MM BM samples. In 42% (46/110) of MM BM samples a greater-than-or-equals 3-fold increase in cyclin D1 mRNA was observed compared to the cyclin D1 level in normal BM. In the remaining group of MM patients the cyclin D1 mRNA levels were comparable to normal donors. Follow-up of 76 MM patients showed no significant (P = 0.35) difference in survival between cyclin D1 positive and negative MM patients. In addition, cyclin D1 dysregulation did not correlate with known prognostic factors.

CONCLUSION

The developed real-time RT-PCR assay for detection of cyclin D1 mRNA levels offers a fast and safe screening for cyclin D1 dysfunction. When a large cohort of MM patients was screened, the cyclin D1 gene was found to be frequently dysregulated, but there was no significant correlation to survival or known prognostic parameters.

Mobilisation of tumour cells along with CD34+ cells to peripheral blood in multiple myeloma

BACKGROUND

Cells belonging to the malignant clone are found in the peripheral blood in myeloma patients. In order to minimise the content of tumour cells in the stem cell product it is crucial to perform stem cell harvest at a time when tumour cells in the peripheral blood are at a minimum.

OBJECTIVE

The aim of the study was to compare the mobilisation kinetics of normal CD34+ cells and myeloma plasma cells during mobilisation with either G-CSF alone or high-dose cyclophosphamide (HDCy) plus G-CSF.

DESIGN AND METHODS

Morning blood samples were drawn each day during mobilisation from start of G-CSF or HDCy and to the end of leukapheresis, and were analysed by flow cytometry for content of CD34+ cells and myeloma plasma cells (CD38+ + CD45-). Tumour cells were also estimated by a patient-specific real-time polymerase chain reaction (PCR) method based on the 5' nuclease TaqMan technology.

RESULTS

Flow cytometry data from 16 patients showed concomitant mobilisation of CD34+ cells and myeloma plasma cells. Seven patients were mobilised twice; first with G-CSF alone and then with HDCy plus G-CSF. There was no difference between the two mobilisation regimens regarding tumour cell mobilisation kinetics. Real-time PCR was performed in one patient and confirmed the mobilisation of tumour cells at the time when CD34+ blood cells were at a maximum.

CONCLUSIONS

Tumour cells are mobilised to the peripheral blood at the same time as CD34+ cells in multiple myeloma patients after priming with both G-CSF alone and HDCy in combination with G-CSF.

Detection of illegitimate rearrangement within the immunoglobulin locus on 14q32.3 in B-cell malignancies using end-sequenced probes

Translocation involving the immunoglobulin heavy chain (IGH) locus is a recurring event in B-cell oncogenesis. The aim of this study was to characterize clones from bacterial artificial chromosome (BAC) libraries and/or bacteriophage P1 artificial chromosome libraries spanning the IGH locus for detection of illegitimate rearrangement within the region by fluorescence in situ hybridization (FISH). In silico analysis of the IGH variable (IGHV) DNA sequence (NT_001716.v1) was performed to identify BAC probes located within the IGHV cluster. Clones of the constant (IGHC) cluster were found in the literature or at http://www.biologia.uniba.it/rmc/. Validation, orientation, and overlap of these probes were confirmed using interphase-, metaphase-, and fiber-FISH. We have identified seven BAC end-sequenced probes (3087C18, 47P23, 76N15, 12F16, 101G24, 112H5, and 151B17) covering 612 kb of the distal IGHV cluster, which, together with probes covering the IGHC cluster (11771 and 998D24), could be used in interphase nuclei and metaphase chromosome analysis. A visual split of the IGHV and IGHC clusters indicating a translocation was analyzed by dual-color FISH in a series of 21 cell lines of different origins. Translocations were found, as expected, in eight of eight myelomas, four of four lymphomas, none of five leukemias, and none of four Epstein-Barr virus-transformed B-lymphoblastoid cell lines. To summarize, we have established a set of IGHV and IGHC probes that can be used for universal screening of illegitimate rearrangement within the IGH locus in B-cell malignancies. These probes allow for routine FISH analysis to detect this early central oncogenic event.

Identification of Two Tetranuclear FeS Clusters on the Ferredoxin-Type Subunit of NADH:Ubiquinone Oxidoreductase (Complex I)

The proton-translocating NADH:ubiquinone oxidoreductase of respiratory chains (complex I) contains one flavin mononucleotide and five EPR-detectable iron-sulfur clusters as redox groups. Because of the number of conserved motifs typical for binding iron-sulfur clusters and the high content of iron and acid-labile sulfide of complex I preparations, it is predicted that complex I contains additional clusters which have not yet been detected by EPR spectroscopy. To search for such clusters, we used a combination of UV/vis and EPR spectroscopy to study complex I from Neurospora crassa and Escherichia coli adjusted to distinct redox states. We detected a UV/vis redox difference spectrum characterized by negative absorbances at 325 and 425 nm that could not be assigned to the known redox groups. Redox titration was used to determine the pH-independent midpoint potential to be -270 mV, being associated with the transfer of two electrons. Comparison with UV/vis difference spectra obtained from complex I fragments and related enzymes showed that this group is localized on subunit Nuo21.3c of the N. crassa or NuoI of the E. coli complex I, respectively. This subunit (the bovine TYKY) belongs to a family of 8Fe-ferredoxins which contain two tetranuclear iron-sulfur clusters as redox groups. We detected EPR signals in a fragment of complex I which we attribute to the novel FeS clusters of complex I.

The muscarinic receptor agonist BuTAC, a novel potential antipsychotic, does not impair learning and memory in mouse passive avoidance

(5R,6R)-6-(3-butylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[3.2.1]octane) (BuTAC) is a novel, selective muscarinic receptor ligand with partial agonist mode of action at muscarinic M2 and M4 and antagonist mode of action at M1, M3 and M5 receptor subtypes in cloned cell lines. BuTAC exhibits functional dopamine receptor antagonism despite its lack of affinity for dopamine receptors, and parasympathomimetic effects in mice are produced only at doses well beyond the doses exhibiting the antipsychotic-like effects. In the present study we investigated the effects of BuTAC and the antipsychotic compounds clozapine, sertindole and olanzapine using one trial passive avoidance with mice as a model of learning and memory. Pharmacologically relevant doses of BuTAC and reference antipsychotics were identified, based on inhibition of apomorphine-induced climbing in mice as an assay measuring antidopaminergic potency. When ratios between the minimum effective dose (MED) for impairment of retention in passive avoidance and the MED for inhibition of apomorphine-induced climbing were calculated, BuTAC displayed a high ratio of >10, compared with clozapine (0.3), sertindole (3) and olanzapine (3). These data suggest that BuTAC is a potential novel antipsychotic which may have favourable effects on aspects of learning and memory.

Regional immune responses with stage-specific antigen recognition profiles develop in lymph nodes of pigs following Ascaris suum larval migration

The early life-cycle of the pig round worm, Ascaris suum, involves well-defined larval development in the liver, lungs and finally the small intestine. Distinct regional immune responses to larval antigens of A. suum were observed in the draining lymph nodes of immunized and challenged pigs during larval migration. This was reflected in a transient enlargement of the stimulated lymph nodes, due to increases in numbers of B cells and CD4 T cells, and the production of A. suum-specific antibody by antibody secreting cell (ASC) cultures. Larval antigen recognition pattern of antibodies in serum, bile and draining lymph node ASC culture supernatant (ASC-probes) was examined by immunoblotting. This revealed distinct organ-specific recognition patterns of larval-specific antigens by the draining lymph nodes at different times after challenge. In particular, an early larval 42 kDa antigen was recognized specifically by ASC-probes of the liver lymph nodes at 7 but not 14 days postchallenge (pc) which was not detected in other lymph nodes, serum or bile of the same pig. Similarly, a late larval antigen of 34 kDa was uniquely detected by lung and jejunal ASC-probes at 14 days pc. These observations demonstrate how development of distinct regional immune responses in tissues with different antigen stimulation can be monitored with ASC-probes and flow cytometry.

The clonal hierachy in multiple myeloma

In this report we evaluated the number and phenotype of blood circulating B-cell subsets at different stages of differentiation in 26 patients with newly diagnosed multiple myeloma (MM). In all patients, plasma cells and/or plasma blasts could be identified by flow cytometry with a mean frequency of 1.20% and 0.07%, respectively. In 76.9% of the patients these cells showed aberrant expression mainly of CD56, CD28 and CD117, none of these markers were found on the earlier B-lymphocytes. Clonal B-cells preceding the plasma blast stage were identified by patient specific IgH RT-PCR on sorted B-cell subsets. The clonal cells included the less differentiated CD38+ CD19+ and CD38-/CD19+ subsets. illustrating that the clonal cells are part of an ongoing differentiation process. Further, the presence of CD38-/CD19+ cells with somatically mutated Cgamma transcripts identical to the tumor-specific Calpha transcript, shows that the clonal hierarchy in myeloma may include memory B-cells.

Optimization of the agar-gel method for isolation of migrating Ascaris suum larvae from the liver and lungs of pigs

Experiments on use of an agar-gel method for recovery of migrating Ascaris suum larvae from the liver and lungs of pigs were conducted to obtain fast standardized methods. Subsamples of blended tissues of pig liver and lungs were mixed with agar to a final concentration of 1% agar and the larvae allowed to migrate out of the agar-gel into 0.9% NaCl at 38 degrees C. The results showed that within 3 h more than 88% of the recoverable larvae migrated out of the liver agar-gel and more than 83% of the obtained larvae migrated out of the lung agar-gel. The larvae were subsequently available in a very clean suspension which reduced the sample counting time. Blending the liver for 60 sec in a commercial blender showed significantly higher larvae recovery than blending for 30 sec. Addition of gentamycin to reduce bacterial growth during incubation, glucose to increase larval motility during migration or ice to increase sedimentation of migrated larvae did not influence larvae recovery significantly.

Frequency and kinetics of polyclonal and clonal B cells in the peripheral blood of patients being treated for multiple myeloma

Recent studies concerning the numbers of circulating clonal B cells in patients with multiple myeloma (MM) have reported conflicting data regarding the exact level and phenotype of clonal B cells and their response to treatment. In this report we document that the peripheral blood tumor burden at presentation was reduced by induction therapy to a low level, regardless of the initial tumor burden. However, the residual clonal compartment persisted before and after transplant. The level of clonal cells showed no correlation with CD19(+) cell levels. In a single patient with MM, high numbers of phenotypically aberrant clonal cells with altered CD19 expression were identified. (Blood. 2000;96:4357-4359)

Sturge-Weber syndrome: indications and results of surgery in 20 patients

OBJECTIVE

To discuss the indications and timing for resective surgery in patients with Sturge-Weber syndrome (SWS) and medication-resistant epilepsy.

BACKGROUND

SWS that causes epilepsy severe enough to merit surgery is rare. Because of the variable natural history of the disease, it is difficult to establish clear-cut indications for surgery and prospective studies are not feasible. Attitudes of clinicians and surgeons remain variable.

METHODS

The authors assessed the presurgical epilepsy profile, criteria for surgery, monitoring techniques, and the postoperative outcome of epilepsy in all patients with SWS consecutively admitted between 1972 and 1990 to two referral centers (Paris and Montreal) and underwent surgery for intractable seizures.

RESULTS

All 20 patients had a minimal postoperative follow-up of 4 years and all but one are still followed by one of the authors. One patient had a callosotomy, five underwent hemispherectomy, and 14 had cortical resection. Despite variability in the age at onset of seizures (range: 2 months to 12 years), age at operation (range: 8 months to 34 years) and surgical methods, almost all patients benefited from surgery. Visually guided complete resection of the pial angioma and underlying cortex, whenever possible, seemed sufficient; results were no better with intraoperative corticography. In children with previous hemiparesis, hemispherectomy proved particularly effective: all five became seizure free. None of the patients showed any aggravation of cognitive impairment following surgery; none of those who were operated on early presented with severe mental retardation, and 13 of 20 became seizure free.

CONCLUSION

Although the natural history of SWS is imperfectly known, increasing duration of seizures and of postictal deficits, increase in atrophy or of calcified lesions or both, are indicative of its progressive nature. Despite the expected heterogeneity that renders formal comparison of the various approaches difficult, the current study provides new evidence to support early surgery in patients with SWS and drug-resistant epilepsy. The authors' results suggest that lesionectomy is a good approach, provided that the pial angioma is unilateral and the resection can be complete.

Nicotine inhaler and nicotine patch as a combination therapy for smoking cessation: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Nicotine replacement therapy is an effective treatment for nicotine-dependent smokers. However, cessation rates are modest, and preliminary studies suggest that combination therapy may be superior. We compared the efficacy of the nicotine inhaler plus nicotine patch vs nicotine inhaler plus placebo patch for smoking cessation.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted in 400 subjects who had smoked 10 or more cigarettes per day for 3 years or longer. Group 1 (n = 200) received the nicotine inhaler plus nicotine patch (delivering 15 mg of nicotine per 16 hours) for 6 weeks, then inhaler plus placebo patch for 6 weeks, then inhaler alone for 14 weeks. Group 2 (n = 200) received the nicotine inhaler plus placebo patch for 12 weeks, then inhaler for 14 weeks. Inhaler was used at a rate of 6 to 12 cartridges per day ad libitum for 3 months and then tapered off. Main outcome measures were complete abstinence (self-reported) and expired carbon dioxide concentration less than 10 ppm.

RESULTS

Group 1 vs group 2 complete abstinence rates were 60.5% and 47.5% at 6 weeks (P =.009), 42.0% and 31.0% at 12 weeks (P =.02), 25.0% and 22.5% at 6 months (P =.56), and 19.5% and 14.0% at 12 months (P =. 14). One-year survival analysis showed a significant association between abstinence and treatment with nicotine inhaler plus nicotine patch (P =.04). Mean nicotine substitution at week 6 was 60.1% (group 1) and 24.6% (group 2) (P<.001). At 12 months, the frequency of respiratory symptoms in abstinent subjects fell significantly and lung function showed a trend toward improvement. The most common adverse events were throat irritation (inhaler) and itching (patch).

CONCLUSIONS

Treatment with the nicotine inhaler plus nicotine patch resulted in significantly higher cessation rates than inhaler plus placebo patch.

Determination of the of rate cross slip of screw dislocations

The rate for cross slip of screw dislocations during annihilation of screw dipoles in copper is determined by molecular dynamics simulations. The temperature dependence of the rate is seen to obey an Arrhenius behavior in the investigated temperature range: 225-375 K. The activation energy and the effective attempt frequency can therefore be extracted from the simulations. The transition state energy for the annihilation process is calculated by identifying the transition state using the nudged elastic band path technique. The two activation energies agree very well, indicating that transition state theory is applicable for this type of process.

The catalytic center in nitrous oxide reductase, CuZ, is a copper-sulfide cluster

The crystal structure of nitrous oxide reductase, the enzyme catalyzing the final step of bacterial denitrification in which nitrous oxide is reduced to dinitrogen, exhibits a novel catalytic site, called Cu(Z). This comprises a cluster of four copper ions bound by seven histidines and three other ligands modeled in the X-ray structure as OH(-) or H(2)O. However, elemental analyses and resonance Raman spectroscopy of isotopically labeled enzyme conclusively demonstrate that Cu(Z) has one acid-labile sulfur ligand. Thus, nitrous oxide reductase contains the first reported biological copper-sulfide cluster.

Randomised trial investigating effect of a novel nicotine delivery device (Eclipse) and a nicotine oral inhaler on smoking behaviour, nicotine and carbon monoxide exposure, and motivation to quit

OBJECTIVE

To monitor the effect of a novel nicotine delivery device that may produce fewer carcinogens (Eclipse) on cigarette smoking, carbon monoxide and nicotine concentrations, and motivation to give up smoking. The smoker's own brand of cigarette and a nicotine replacement product (Nicotrol inhaler) were used as comparisons.

DESIGN

After baseline data were recorded, smokers were randomised to either Eclipse or inhaler for two weeks and then switched to the other product for another two weeks. Thereafter a second baseline was obtained.

SETTING AND PARTICIPANTS

Fifty smokers were included and data are reported for the 40 with complete data sets. The smokers were not trying to quit but were interested in trying a new product to reduce their risk. They visited a smoking clinic 10 times during the six week period of the trial.

INTERVENTION

No counselling to aid reduction by Eclipse or inhaler was given.

MAIN OUTCOME MEASURES

At each visit smoking status and carbon monoxide concentrations were recorded. In half of the visits withdrawal symptoms, attitudes towards smoking, heart rate, and blood nicotine concentrations were also recorded.

RESULTS

Eclipse use decreased the number of cigarettes smoked per day (cpd) from 19.1 cpd at baseline to 2.1 cpd (p < 0.001), but increased carbon monoxide concentrations in parts per million (ppm) from 21.0 ppm to 33.0 ppm (p < 0.001). A similar decrease in cigarettes smoked per day was seen with the Nicotrol inhaler, from 19.1 cpd to 4.8 cpd (p < 0.001), but carbon monoxide decreased from 21.0 ppm to 12.7 ppm (p < 0.001). The blood nicotine concentration remained fairly stable with Eclipse, increasing slightly from 16.8 ng/ml to 18.0 ng/ml, while for the inhaler a significant drop was noted, from 16.8 ng/ml to 12. 2 ng/ml (p < 0.002). Craving and withdrawal did not increase with Eclipse. Few significant adverse events occurred with Eclipse.

CONCLUSIONS

Eclipse can dramatically decrease cigarette consumption without causing withdrawal symptoms or decreases in nicotine concentrations or motivation to quit altogether. Unlike the inhaler, Eclipse produces an increase in carbon monoxide concentration. Thus Eclipse may not be a safer cigarette.

Quantitation of minimal residual disease in multiple myeloma using an allele-specific real-time PCR assay

OBJECTIVE

To develop a real-time PCR method, based on the 5'nuclease TaqMan technology, for quantitation of clonal cells in multiple myeloma (MM).

MATERIALS AND METHODS

The real-time quantitative PCR method incorporates both an allele-specific oligonucleotides (ASO) primer and an ASO dual-labeled fluorogenic probe (ASO TaqMan probe). The ASO primer and probe corresponded to the complementary determining region 3 (CDR3) of the rearranged immunoglobulin heavy chain gene (IgH). With the use of a sequence detector, PCR product accumulation was measured through the ASO TaqMan probe. The real-time PCR method was compared with flow cytometric quantitation of myeloma plasma cells.

RESULTS

The application of the real-time quantitative ASO IgH PCR method is illustrated by a sequential analysis of minimal residual disease (MRD) in bone marrow (BM) samples from myeloma patients undergoing peripheral blood stem cell (PBSC) transplantation. The real-time PCR method was able to quantitate residual malignant cells in BM samples from patients who were considered to be in complete remission. Further, it was illustrated that a potential problem in determining tumor cell content in myeloma BM samples is the heterogeneous infiltration of the marrow.

CONCLUSION

The application of the real-time PCR method provides a sensitive, highly specific, and reproducible quantitation of myeloma cells.

Muscarinic receptor agonists decrease cocaine self-administration rates in drug-naive mice

(5R,6R)-6-(3-Propylthio-1,2,5-thiadiazol-4-yl)-1-azabicyclo[ 3.2.1]octane (PTAC) is a selective muscarinic receptor ligand. The compound exhibits high affinity for central muscarinic receptors with partial agonist mode of action at muscarinic M(2) and M(4) and antagonist mode of action at muscarinic M(1), M(3) and M(5) receptor subtypes. The compound was earlier reported to exhibit functional dopamine receptor antagonism in rodents despite its lack of affinity for dopamine receptors. In the present study, we report that PTAC, as well as the muscarinic receptor agonists pilocarpine and oxotremorine, dose-dependently decreased rates of intravenous self-administration (fixed ratio 1) of the indirect dopamine receptor agonist cocaine in drug naive mice. Similar decreases in cocaine self-administration rates were obtained with the dopamine receptor antagonists olanzapine, clozapine, risperidone, fluphenazine and haloperidol. These findings suggest that compounds with partial muscarinic receptor agonist mode of action may be used in the medical treatment of cocaine abuse.

Characterization of two novel redox groups in the respiratory NADH:ubiquinone oxidoreductase (complex I)

The proton-pumping NADH:ubiquinone oxidoreductase is the first of the respiratory chain complexes in many bacteria and mitochondria of most eukaryotes. The bacterial complex consists of 14 different subunits. Seven peripheral subunits bear all known redox groups of complex I, namely one FMN and five EPR-detectable iron-sulfur (FeS) clusters. The remaining seven subunits are hydrophobic proteins predicted to fold into 54 alpha-helices across the membrane. Little is known about their function, but they are most likely involved in proton translocation. The mitochondrial complex contains in addition to the homologues of these 14 subunits at least 29 additional proteins that do not directly participate in electron transfer and proton translocation. A novel redox group has been detected in the Neurospora crassa complex, in an amphipathic fragment of the Escherichia coli complex I and in a related hydrogenase and ferredoxin by means of UV/Vis spectroscopy. This group is made up by the two tetranuclear FeS clusters located on NuoI (the bovine TYKY) which have not been detected by EPR spectroscopy yet. Furthermore, we present evidence for the existence of a novel redox group located in the membrane arm of the complex. Partly reduced complex I equilibrated to a redox potential of -150 mV gives a UV/Vis redox difference spectrum that cannot be attributed to the known cofactors. Electrochemical titration of this absorption reveals a midpoint potential of -80 mV. This group is believed to transfer electrons from the high potential FeS cluster to ubiquinone.