Posterolateral fusion in acute traumatic thoracolumbar fractures: a comparison of demineralized bone matrix and autologous bone graft

INTRODUCTION Alternative fusion expanders are in clinical use for instrumented posterolateral fusion (PLF) to avoid donor site morbidity in autologous bone graft (ABG) harvesting. Purpose of this study was to evaluate demineralized bone matrix (DBM) in PLF as alternative to the gold standard of ABG in acute traumatic vertebral body fractures of the thoracolumbar spine. MATERIAL AND METHODS We retrospectively identified 101 patients with acute traumatic vertebral body fractures of the thoracic and lumbar spine who were treated with instrumented PLF in our level one trauma center between 2005 and 2011. Patients with a primary paraplegia, osteodepriving disease or loss to follow-up had been excluded. Until August 2008, autologous bone graft harvested from the posterior iliac crest was used in PLF (control group n = 46). Starting September 2008, DBM was used as fusion expander in PLF (study group n = 16). Clinical and radiological evaluation was performed with a minimum followup of 18 months to assess the clinical and radiological outcome. RESULTS We found a fusion rate of 94% in patients undergoing PLF with the use of DBM and 100% with the use of ABG. There was one major complication of deep infection in the DBM group and two cases of superficial wound infection in the ABG group. We discovered a trend of reduced operating time with the use of DBM. CONCLUSIONS DBM leads to a similar fusion rate as the use of ABG in patients undergoing PLF for acute traumatic vertebral body fractures of the thoracic and lumbar spine. DBM is associated with reduced operating time.

LEVEL OF EVIDENCE III

case-control study Key words: demineralized bone matrix instrumented posterolateral fusion, acute traumatic vertebral body fracture, thoracolumbar spine, autologous bone graft.

Mir-17∼92 promotes terminal differentiation of effector CD8 T cells by lowering TCR stimulation threshold (LYM4P.750)

MicroRNAs are small RNAs (∼22 nucleotides) that regulate gene expression via post-transcriptional mechanisms, and are emerging as major players in immune cell development and function. Using dual strategy of conditional deletion or constitutive overexpression of miR-17∼92, we have recently shown that miR-17∼92 has a critical CD8 T cell-intrinsic role in driving terminal effector differentiation by promoting proliferation (Khan, et al., 2013, Blood). We hypothesized that miR-17∼92 increases the sensitivity of CD8 T cells to TCR stimulation, thus driving proliferation and terminal differentiation. Indeed, when we overexpressed miR-17∼92 in effector CD8 T cells, we observed heightened levels of proximal phosphorylation events downstream of TCR. While PTEN and PD-1 (negative regulators of T cell stimulation) were downregulated upon overexpression of miR-17∼92, dramatic potentiation of TCR signal transduction occurred as evidenced by 50-fold upregulation of ribosomal S6 Kinase activity compared to WT. Converse results were obtained when miR-17∼92 was deleted, and about 10-folds higher levels of peptide-MHC were needed to induce TCR signals to levels similar to WT. Consistent with these observations, under conditions of limiting TCR stimulation, in vivo expansion of virus-specific miR-17∼92-deleted CD8 T cells was also severely compromised. Our data, altogether present a novel role of miR-17∼92 in regulating TCR sensitivity during CD8 T cell activation and effector differentiation.

Vitamin D regulates CD8 T cell expansion and immune memory to infections (IRM4P.502)

Epidemiological studies implicate a potential role of vitamin D in modulating immune responses to infections and vaccines. In this study we analyzed the contribution of vitamin D signals to the development and maintenance of antigen-specific memory CD8 T cell responses during a viral infection. Using the vitamin D receptor (VDR)-deficient murine model, we found that lack of vitamin D signals resulted in a dysregulated CD8 T cell expansion program, which was largely attributable to cell-extrinsic effects. Investigation of events proximal to TCR activation demonstrated a delayed yet sustained priming of antigen-specific CD8 T cells in the absence of vitamin D signals. In spite of a larger ensuing effector CD8 T cell pool generated in the absence of vitamin D signals, the final memory pool was smaller. Interestingly, within both effector and memory CD8 T cell pools, we observed a bias towards CD8 T cells specific for immunodominant determinants, resulting in a restricted repertoire of antigen-specific CD8 T cells in the absence of vitamin D signals. Collectively, these studies delineate a critical role of vitamin D in regulating the quantity and quality of adaptive T cell immunity. Importantly, our studies have direct impact on the efficacy of vaccines, owing to disparate nutritional states of vitamin D that are currently seen cross-sectionally around the world.

[Aortic aneurysms and aortic dissection: epidemiology, pathophysiology and diagnostics]

Aortic aneurysms and aortic dissection represent a significant health risk due to the demographic developments and current life styles. The mortality of ruptured aortic aneurysms is up to 80 % and the prevalence of aneurysms varies depending on the localization (thoracic or abdominal). Most commonly affected is the infrarenal abdominal aorta; however, there is evidence that the prevalence is diminishing but in contrast the incidence of thoracic aortic aneurysms is increasing. Aortic dissection is often fatal and is the most common acute aortic disease but the incidence is presumed to be underestimated. The pathogenesis of aortic aneurysms is manifold and is based on an interplay between degenerative, proteolytic and inflammatory processes. An aortic dissection arises from a tear in the intima which results in a separation of the aortic wall layers with infiltration of bleeding and the danger of aortic rupture. Various genetic disorders of connective tissue promote degeneration of the aortic media, most notably Marfan syndrome. Risk factors for aortic aneurysms and aortic dissection are nicotine abuse, arterial hypertension, age and male gender. Aortic aneurysms initially have an uneventful course and as a consequence are mostly discovered incidentally. The clinical course and symptoms of aortic dissection are very much dependent on the section of the aorta affected and the manifestations are manifold. Acute aortic dissection is in 80 % of cases first manifested as sudden extremely severe pain. The diagnostics and subsequent course control can be achieved by a variety of imaging procedures but the modality of choice is computed tomography.

Diurnal changes of lower leg volume in obese and non-obese subjects

BACKGROUND/AIM

Obesity is a risk factor for chronic venous disease. However, the mechanisms behind this association are poorly understood. We tested the hypothesis that obese subjects have a higher diurnal leg volume increase compared with non-obese subjects.

METHODS

In this prospective cohort study including obese (body mass index, BMI ≥30 kg m(-)(2)) and non-obese (BMI ≤25 kg m(-)(2)) subjects without venous insufficiency, lower leg volume was assessed by optoelectronic volumetry in the morning and in the evening. All subjects underwent duplex ultrasound and light reflection rheography (venous pump power and venous refill time, VRT) to investigate lower extremity venous function. A pedometer was carried between the morning and evening visit to assess the daily number of footsteps. A backward multivariable linear regression model was used to determine factors associated with diurnal lower leg volume increase.

RESULTS

Forty-two limbs in 24 obese subjects and 29 limbs in 15 non-obese subjects were analyzed. Obese subjects had larger common femoral vein diameters (17.1±2.4 vs 15.5±2.4 mm, P<0.01) and slower peak, mean and minimal velocities (25.1±10.6 vs 44.3±14.3 cm s(-1); 6.8±2.4 vs 12.7±5.6 cm s(-1); -0.2±6.4 vs -6.3±11.9 cm s(-1); P<0.01 for all) than non-obese subjects. VRT was shorter in obese subjects (40.5±15.0 vs 51.0±12.1 s, P<0.01) and decreased significantly in the course of the day only in obese subjects (P<0.01). Obesity, male gender, CEAP (Clinical-Etiology-Anatomy-Pathophysiology) class, total time between the two visits and difference between morning and evening VRT were positively associated with higher lower leg volume increase; morning VRT and the total number of footsteps showed a negative association (P<0.04 for all).

CONCLUSION

Obesity was found to be an independent predictor of higher diurnal leg volume increase. One potential mechanism is a progressive failure of venous valve function in the course of the day in obese subjects.

Treatment for long-segment femoro-popliteal obstructions: initial experience with a 4-F compatible self-expanding nitinol stent and review of the literature

AIM

The aim of this paper was to evaluate the efficacy of a novel 4-F compatible self-expanding Nitinol stent for the treatment of long femoro-popliteal obstructions.

METHODS

This retrospective analysis includes patients with femoro-popliteal obstructions ≥ 120 mm in length, treated with a novel Nitinol stent (Pulsar-18) between February 2010 and December 2011. Patients were categorized as either intermittent claudication (IC) or critical limb ischemia (CLI). Primary endpoint was primary patency, secondary endpoints were target lesion revascularization (TLR).

RESULTS

A total of 31 patients (IC: N=18 and CLI: N=13) were included in the present series. Mean age was 73.3 ± 10.1 years and 71% (22/31) of the patients were male. Primary intervention was performed in 77.4% (24/31) of the patients and re-do revascularization in the remaining. Mean lesion length of femoro-popliteal obstructions was 163.5 ± 32.5 mm. Technical success was obtained in all patients. Mean follow-up duration was 316 ± 198 days. Primary patency rates were 83.3% in IC and 80.0% in CLI patients at 6 months and 64.1% and 54.9% at 12 months, respectively (P=0.84). Target lesion revascularization occurred in 5.6% of IC and 20.0% of CLI patients at 6 months and in 14.1% and 36.0% at 12 months, respectively (P=0.43).

CONCLUSION

Endovascular stenting of long femoro-popliteal lesions using the Pulsar-18 stent provides acceptable results with patency and restenosis rates comparable with data from literature for stenting of long femoro-popliteal obstructions.

The relationship between Bayesian motor unit number estimation and histological measurements of motor neurons in wild-type and SOD1(G93A) mice

OBJECTIVE

To assess the relationship between Bayesian MUNE and histological motor neuron counts in wild-type mice and in an animal model of ALS.

METHODS

We performed Bayesian MUNE paired with histological counts of motor neurons in the lumbar spinal cord of wild-type mice and transgenic SOD1(G93A) mice that show progressive weakness over time. We evaluated the number of acetylcholine endplates that were innervated by a presynaptic nerve.

RESULTS

In wild-type mice, the motor unit number in the gastrocnemius muscle estimated by Bayesian MUNE was approximately half the number of motor neurons in the region of the spinal cord that contains the cell bodies of the motor neurons supplying the hindlimb crural flexor muscles. In SOD1(G93A) mice, motor neuron numbers declined over time. This was associated with motor endplate denervation at the end-stage of disease.

CONCLUSION

The number of motor neurons in the spinal cord of wild-type mice is proportional to the number of motor units estimated by Bayesian MUNE. In SOD1(G93A) mice, there is a lower number of estimated motor units compared to the number of spinal cord motor neurons at the end-stage of disease, and this is associated with disruption of the neuromuscular junction.

SIGNIFICANCE

Our finding that the Bayesian MUNE method gives estimates of motor unit numbers that are proportional to the numbers of motor neurons in the spinal cord supports the clinical use of Bayesian MUNE in monitoring motor unit loss in ALS patients.

Anisakis simplex (s.s.) larvae in wild Alaska salmon: no indication of post-mortem migration from viscera into flesh

The prevalence, mean intensity and distribution of Anisakis nematode third-stage larvae (L3) in the muscle and viscera of wild-caught chum salmon Oncorhynchus keta, pink salmon O. gorbuscha and sockeye salmon O. nerka were compared immediately after catch. Salmon were collected during the fishing season in July 2007 in Bristol Bay and Prince William Sound close to Cordova, Alaska (USA). All fish were infected, and more than 90% of the nematode larvae were found in the edible muscle meat. The isolated anisakid L3 were genetically identified as A. simplex (s.s.). The distribution of nematodes in the muscle meat of fresh-caught salmon was examined in 49 O. keta, 50 O. nerka and 12 O. gorbuscha from Cordova. Most of the larvae were detected in the muscle parts around the body cavity, but nematodes were also found in the tail meat and epaxial muscle (loins). The mean intensity of Anisakis larvae in the edible part was 21 individuals for O. gorbuscha, 62 individuals for O. keta and 63 individuals for O. nerka. No difference in the intensity of Anisakis larvae in the hypaxial muscle was found between fresh-caught and immediately gutted salmon and individuals stored ungutted for 24 h either on ice or in refrigerated sea water.

Determination of nicotine and cotinine in human serum by means of LC/MS

As part of a joint clinical research project to study the effects of nicotine on the brain, a HPLC electrospray ionisation mass spectrometry method with a solid-phase extraction sample preparation was developed for the quantitative determination of nicotine and cotinine in human serum in volunteers. The measured concentrations of nicotine and cotinine were used as control for smoking behaviour. A X-Bridge-column from Waters, and a SSQ 7000 single quadropole mass spectrometer with a TSP liquid chromatographic system were used. The method includes a simple and robust sample preparation and this assay has been shown to be of a sufficient sensitivity for this application. The limits of quantification were 5 and 2ng/ml for cotinine and nicotine, respectively. A simultaneous study was conducted to measure nicotine receptor availability and the vigilance in the same group of volunteers.

[Perioperative fatal bleeding: link between acetabular anchoring of a cementless implant]

This case report concerns a 75-year-old patient who suffered haemorrhagic shock and mors in tabula during implantation of a total hip arthroplasty. The cause was established as an injury of the external iliac vein, probably as a result of the predrilling of holes for the anchoring screws and pegs. The surgical method and topographic anatomy of the operating area are presented. Such vascular injuries are a rare but life-threatening complication of this procedure; the literature quotes a frequency of about 0.3%. So far, no fulminate venous bleeding process has been reported. Complications in such operations cannot always be avoided. However, detailed knowledge of the acetabular geometry can provide more safety for the surgeon when carrying out the secondary anchoring of a press-fit implant.

Treatment of osteonecrosis of the humeral head with cementless surface replacement arthroplasty

BACKGROUND

Osteonecrosis of the humeral head is a disabling condition that can lead to joint destruction with persistent pain and dysfunction. The aim of the present study was to examine cementless humeral surface replacement arthroplasty as a treatment option for posttraumatic and nontraumatic osteonecrosis.

METHODS

Between 2002 and 2005, seventeen shoulders with posttraumatic (n = 8) or nontraumatic (n = 9) osteonecrosis of the humeral head were treated with cementless humeral replacement arthroplasty. The mean proportion of the humeral head that was occupied by necrotic bone was 18.6% (range, 8.9% to 30.9%). The mean duration of follow-up was three years. Constant scores, patient satisfaction, and complications were recorded. Volumetric measurements of the necrotic areas and signs of implant loosening were analyzed with use of standardized radiographs.

RESULTS

The mean Constant score for the entire cohort improved significantly from 31 to 62 points (34% to 75% when adjusted by age and sex) (p < 0.0001). There were also significant improvements in mean shoulder flexion (from 87 degrees to 139 degrees), abduction (from 64 degrees to 120 degrees), and external rotation (from 2 degrees to 27 degrees). The final values for the Constant score, abduction, and power were significantly higher for the nontraumatic group than for the posttraumatic group. Fourteen patients (fifteen shoulders) were very satisfied (eleven shoulders) or satisfied (four shoulders), and two patients (two shoulders) were somewhat disappointed with the postoperative result. Signs of implant loosening were not observed. One patient had a wound infection that required surgical débridement and antibiotic therapy. To date, no implant revisions have been necessary.

CONCLUSIONS

Cementless humeral surface replacement arthroplasty is a potentially bone-preserving option for patients with posttraumatic and nontraumatic osteonecrosis of the humeral head. Even in the presence of bone loss of as much as 31% of the humeral head, implant loosening was not observed. Good functional results and relief of pain in combination with a low complication rate can be achieved in the short term.

Determination of terephthalic acid isopropylamide in urine with a liquid chromatography/mass spectrometry (LC/MS) method

A sensitive and simple liquid chromatography/mass spectrometry (LC/MS) method was developed for the determination of terephthalic acid isopropylamide, the final metabolite of procarbazine in human urine. A solid-phase extraction with C(18) cartridges was used followed by LC/MS with a single mass spectrometer (SSQ 7000 from Finnigan). Terephthalic acid isobutylamide was the internal standard. The quantification limit was 30 ng/mL in urine (6 x noise). This assay was applied for drug monitoring of terephthalic acid isopropylamide in urine after oral administration of procarbazine in children and adolescents with Hodgkin lymphomas.

The subclinical incidence of CTS in pregnancy: Assessment of median nerve impairment in asymptomatic pregnant women

PURPOSE

The true incidence of pregnancy related carpal tunnel syndrome (PRCTS) is unknown. Most of the diagnoses of PRCTS are made based only on clinical symptoms. Here, we report a prospective controlled clinical trial assessing the electrophysiological changes in pregnant women to provide objective measure of the median nerve function.

METHODS

Pregnant women in the third trimester (n=69) and age-matched non-pregnant women (n=40) asymptomatic for CTS were included in the study. Nerve conduction studies of the median and ulnar nerves across the carpal tunnel were bilaterally performed with the standard techniques.

RESULTS

All the median sensory nerve conduction studies (amplitude, latency and velocity) performed from the ring finger and palmar region to wrist showed significant prolongation of median nerve conduction in the pregnant women compared with the control group (*p</=0.05). Median sensory nerve latencies from palmar branches to wrist were significantly longer in the pregnant group (**p<0.01). Sensory nerve action potential amplitudes recorded in the palmar region were smaller in the pregnant women (45.1AmicroV) than in the control group (56.5AmicroV). Ulnar motor and sensory conduction studies showed no significant difference between the pregnant women and the control group. According to the mean values of median nerve conduction velocity, 8 (11%) pregnant women were electrophysiologically diagnosed as CTS and four of these cases became symptomatic later during pregnancy or after delivery.

CONCLUSIONS

Median nerve impairment occurs even in asymptomatic pregnant women. The electrophysiological characteristics of this impairment are defined and the pathophysiology of PRCTS is discussed. Electrophysiological evaluation is a tolerable and feasible technique for the early diagnosis of PRCTS.

[Anemia of unknown origin: paraneoplastic?]

Bei einer 88-jährigen Patientin blieben trotz klinischer Abklärung Anämie und AZ-Verschlechterung unklar; sie starb im hämorrhagischen Schock. Autoptisch wurde eine Polyarteriitis nodosa mit Befall aller viszeralen Organe und mit Duodenalulzera sowie ein metastasiertes Nierenzellkarzinom gefunden. Die Vaskulitis wird als paraneoplastisches Syndrom bei okkultem Neoplasma diskutiert.

Primary mouse hepatocytes for systems biology approaches: a standardized in vitro system for modelling of signal transduction pathways

Complex cellular networks regulate regeneration, detoxification and differentiation of hepatocytes. By combining experimental data with mathematical modelling, systems biology holds great promises to elucidate the key regulatory mechanisms involved and predict targets for efficient intervention. For the generation of high-quality quantitative data suitable for mathematical modelling a standardised in vitro system is essential. Therefore the authors developed standard operating procedures for the preparation and cultivation of primary mouse hepatocytes. To reliably monitor the dynamic induction of signalling pathways, the authors established starvation conditions and evaluated the extent of starvation-associated stress by quantifying several metabolic functions of cultured primary hepatocytes, namely activities of glutathione-S-transferase, glutamine synthetase, CYP3A as well as secretion of lactate and urea into the culture medium. Establishment of constant metabolic activities after an initial decrease compared with freshly isolated hepatocytes showed that the cultured hepatocytes achieve a new equilibrium state that was not affected by our starving conditions. To verify the highly reproducible dynamic activation of signalling pathways in the in vitro system, the authors examined the JAK-STAT, SMAD, PI3 kinase, MAP kinase, NF-kappaB and Wnt/beta-catenin signalling pathways. For the induction of gp130, JAK1 and STAT3 phosphorylation IL6 was used, whereas TGFbeta was applied to activate the phosphorylation of SMAD1, SMAD2 and SMAD3. Both Akt/PKB and ERK1/2 phosphorylation were stimulated by the addition of hepatocyte growth factor. The time-dependent induction of a pool of signalling competent beta-catenin was monitored in response to the inhibition of GSK3beta. To analyse whether phosphorylation is actually leading to transcriptional responses, luciferase reporter gene constructs driven by multiple copies of TGFbeta-responsive motives were applied, demonstrating a dose-dependent increase in luciferase activity. Moreover, the induction of apoptosis by the TNF-like cytokine Fas ligand was studied in the in vitro system. Thus, the mouse hepatocyte in vitro system provides an important basis for the generation of high-quality quantitative data under standardised cell culture conditions that is essential to elucidate critical hepatocellular functions by the systems biology approach.

Symmetry-based determination of space-time functions in nonequilibrium growth processes

We study the space-time correlation and response functions in nonequilibrium growth processes described by linear stochastic Langevin equations. Exploiting exclusively the existence of space- and time-dependent symmetries of the noiseless part of these equations, we derive expressions for the universal scaling functions of two-time quantities which are found to agree with the exact expressions obtained from the stochastic equations of motion. The usefulness of the space-time functions is illustrated through the investigation of two atomistic growth models, the Family model and the restricted Family model, which are shown to belong to a unique universality class in 1+1 and 2+1 space dimensions. This corrects earlier studies which claimed that in 2+1 dimensions the two models belong to different universality classes.

Factors of severity at admission during an epidemic of dengue 1 in New Caledonia (South Pacific) in 2003

We report a retrospective study of an epidemic of dengue in New-Caledonia (South Pacific) in 2003 among adult inpatients. The aim was to establish clinical and biological criteria for the severity of the infection at the time of admission. During 7 months, all inpatients older than 15 y having a laboratory-confirmed diagnosis of dengue fever (IgM or PCR) were included (n=170). Two groups were defined: severe cases (death and/or transfer to intensive care unit, n=24) and benign cases (n=146). Data were analysed using Epi-Info software. Univariate analysis showed that shock, haemorrhage and neurological complications were significantly more frequent in serious cases, respectively 37.5% vs 0.7%, 62.5% vs 32.2%, 25% vs 9.6% (p<0.05). Relevant biological criteria were: creatinine > 140 micromol/l (OR 12 (95% CI 3.93-37.44)), free bilirubin > 18 micromol/l (OR 12.69 ( 95% CI 2.88-59.5)), amylase > 220 UI/l (OR 27.34 (95% CI 4.57-210)) and platelets < 45,000/mm3 (OR 4.35 (95% CI 1.43-14.2)) with p<0.005 (VPP = 100% for association of 3 criteria). We suggest this combination of 4 biological criteria inclines to severity.

Distribution of Streptococcus pneumoniae serotypes responsible for penicillin resistance and the potential role of new conjugate vaccines in New Caledonia

Invasive pneumococcal disease is a significant cause of morbidity and mortality worldwide. The aim of this study was to establish the serotypes responsible for pneumococcal disease and the serotypes responsible for penicillin resistance in Noumea, New Caledonia. Isolates of Streptococcus pneumoniae from all body sites referred to the Microbiology Department of the Pasteur Institute in New Caledonia between May 1999 and May 2001 had serotyping and susceptibility testing performed. Basic demographic data on patients were also collected. A total of 298 isolates were included in the study. The most common serotypes were types 1 (20%), 23F (10%), 12F (8%), 19F (8%), and 6B (5%). The serotype distribution differed significantly with age, site of collection, and ethnicity. Overall, 280 of 298 (94%) of the isolates had serogroups that are included in the 23-valent vaccine. However, only 14 of 20 (70%) of the isolates associated with invasive disease from children younger than 5 years of age and 26 of 113 (23%) of invasive isolates from patients more than 5 years of age were included in the new 7-valent conjugate vaccine. Overall, reduced susceptibility to penicillin was found in 43 of 298 (14.4%) of the isolates, with 13% falling into the intermediate resistance category and only 5 (2%) being high-level resistant. A higher prevalence of penicillin resistance occurred in younger age groups and in European patients and involved specifically certain serotypes. The 7-valent conjugate pneumococcal vaccine has potential benefit for the New Caledonian population under 5 years of age and should be considered for future vaccines schedules.

CYP3A4, CYP2C9 and CYP2B6 expression and ifosfamide turnover in breast cancer tissue microsomes

Ifosfamide is a prodrug that requires bioactivation by cytochrome P450 for antitumour activity. Up to now, little is known, to what extent in addition to the liver the ifosfamide metabolism may occur intratumorally. For this purpose, we investigated the expression of CYP3A4, CYP2C9 and CYP2B6 in breast cancer tissue using Western Blotting. Ifosfamide turnover was determined by detection of metabolites of the ifosfamide 4-hydroxylation and N-dechloroethylation in tumour microsomal incubations using HPLC/UV and LC/MS. The results demonstrate that all mammary tumours (n=11) reveal CYP3A4 expression; contents varied from 0.5 to 63 pmol mg(protein)(-1). CYP2C9 (n=9) was present in all tested breast tumour samples, too, while CYP2B6 (n=10) protein could not be detected. All measured breast cancer microsomes (n=4) showed an ifosfamide N-dechloroethylation capacity in the range from 0.04 to 0.21 pmol min(-1) mg(protein)(-1), while metabolites of the 4-hydroxylation could not be determined. In conclusion, the detected presence of CYP3A4 and CYP2C9 in breast tumours offers the possibility of intratumoral turnover of ifosfamide. For the first time in the literature, we could demonstrate a turnover of ifosfamide by microsomal preparations from human breast cancer tissue. A calculated modulation of intratumoral ifosfamide turnover could considerably influence its therapeutic efficiency.

[Knowledge of "Hardship Exemptions" in statutory sickness insurance]

OBJECTIVES

The German Statutory Sickness Fund comprises about 90 % of the total population. There are special relief or 'hardship' regulations in the Statutory Sickness Fund (the 'Härtefallregelungen') exempting those insured persons from co-payment for whom the co-payments would be an undue financial burden. The most important research questions are: How many of the insured persons do actually know about the possibility of being exempted? How did this group learn about the possibility? How many insured are not exempted from co-payment although they are entitled to be exempted? Why didn't they apply? According to our knowledge there is no comparable national or international study in this field of research.

METHODS

The data for the empirical study are collected in a Statutory Sickness Fund in the city of Augsburg (Southern Germany). 18 238 insured (pre-selected as not being exempted from co-payments, but probably entitled to be exempted) were addressed with a very short questionnaire in September 2000. They were asked about their household income, the number of the household members and the money spent for co-payments for medicaments, dental prostheses and other health-related services, in order to identify those entitled to be exempted, and a control group. Among those who responded 1.002 persons were interviewed by CATI (Computer Assisted Telephone Interview).

RESULTS

Within the study group interviewed by CATI there was only limited knowledge about the "Härtefallregelungen". About two-thirds of the respondents (61.58 %) were unfamiliar with the possibility of getting an annual reimbursement of the co-payments. Less than one-third (27.78 %) knew nothing about the regulation of being totally exempted from co-payments. Most persons learnt about the regulations from friends and relatives, but few from physicians and other health professionals. One of the reasons most frequently mentioned for not applying for the "Härtefallregelungen" was a presumably too high income. Reasons which lie within the formalities of the application or refer to the potentially embarrassing situation were reported less often.

CONCLUSION

Knowledge about the possibilities of being exempted from co-payments for medicaments and other health-related services and goods should be increased. With most of the respondents having learnt about the "Härtefallregelungen" from friends and relatives, patients could get relevant information from physicians and other health professionals more frequently. As financial aspects are the reasons reported most for not applying for the "Härtefallregelungen", the information policy could be enhanced e. g. by simplified examples for calculating the relevant income for being entitled. This way there is a chance that all insured persons who are entitled will actually benefit from the "Härtefallregelungen".

[The seroprevalence of HIV in pregnant women in New Caledonia: an assessment of 1 year of surveillance]

OBJECTIVES

To evaluate the HIV prevalence among pregnant women in New-Caledonia and to analyse the uptake of testing among the patients according to their demographic data.

METHOD

The study was based on statistical exploitation of anonymously recorded HIV test results during the follow-up of pregnant women. The first 12-month assessment of this monitoring (April 1999--March 2000) is reported.

RESULTS

88.6% of the 3380 patients were tested for HIV, significantly less in Wallisian and Melanesian groups of women. Two results were positive, which corresponds to a prevalence of 0.66 +/- 0.45 per thousand (0.21-1.11 per 1000) within the studied group. Although our study is not representative of this situation, lack of testing for women undergoing an abortion was frequent.

CONCLUSION

This study indicates that offering HIV testing in pregnancy follow-up is fairly systematic and most often accepted. Evidently, there is a need for adjusting of pre-test counselling to the cultural and ethnic characteristics of the woman, to the preparedness of medical staff as well as to the problem of HIV screening in abortion management. Our prevalence data also show that New-Caledonia ranks among countries of low endemicity for HIV where pregnant women are concerned.

Cyclophosphamide and related anticancer drugs

This article presents an overview of the methods of bioanalysis of oxazaphosphorines, in particular, cyclophosphamide, ifosfamide, and trofosfamide as well as their metabolites. The metabolism of oxazaphosphorines is complex and leads to a large variety of metabolites and therefore the spectrum of methods used is relatively broad. The various methods used are shown in a table and the particularly important assays are described.

Gender difference in ifosfamide metabolism by human liver microsomes

Pharmacokinetic gender-dependent differences in cytochrome P450-mediated drug metabolism, especially CYP3A4, and their clinical implications are increasingly apparent. CYP3A4 seems to be the most important CYP isoform in both bioactivation and N-dechloroethylation of the alkylating prodrug ifosfamide, but informations about possible gender-related differences are lacking. Therefore we compared in 10 male and 10 female liver microsomal preparations the contents and activities of specific isoenzymes, involved in both metabolic pathways, especially CYP3A4, further CYP2A6, CYP2C9 and CYP2B6 and measured the in vitro activities of these microsomes in the ifosfamide 4-hydroxylation and N-dechloroethylation using high-sensitive HPLC/MS and -UV detection methods. Statistically significant differences between male and female livers were found in the mean CYP3A4 contents and activities. These differences had no consequences on the ifosfamide 4-hydroxylation activities of liver microsomes in vitro. In contrast, in the ifosfamide N-dechloroethylation reaction we found a statistically significant difference between the liver microsomes of male and female patients (0.13 +/- 0.05 nmol/min nmol P450 vs. 0.28 +/- 0.13 nmol/min x nmolP450, respectively). In conclusion, we firstly demonstrated such gender-related difference in the ifosfamide N-dechloroethylation, which could result in a higher risk of partly severe neurotoxic side effects in female patients.

Ecm10, a novel hsp70 homolog in the mitochondrial matrix of the yeast Saccharomyces cerevisiae

Members of the heat shock protein 70 (Hsp70) family are found in most of the compartments of eukaryotic cells where they play essential roles in protein metabolism. In yeast mitochondria, two Hsp70 proteins are known: Ssc1 and Ssq1. We identified Ecm10 as a third Hsp70 protein in the mitochondrial matrix. Ecm10 shares 82% amino acid identity with Ssc1 and 54% with Ssq1. Overexpression of Ecm10 mitigates protein import defects in ssc1 mutants suggesting that Ecm10 can play a role in protein translocation. Like Ssc1, Ecm10 interacts with the nucleotide exchange factor Mge1 in an ATP-dependent manner. Deletion of ecm10 leads to synthetic growth defects with ssc1 mutations at low temperature. Our data suggest an overlapping function of Ecm10 and Ssc1.

The cytochrome bc1 and cytochrome c oxidase complexes associate to form a single supracomplex in yeast mitochondria

The mitochondrial electron transport chain complexes are large multisubunit complexes embedded in the inner membrane. We report here that in the yeast Saccharomyces cerevisiae, the cytochrome bc(1) and cytochrome c oxidase complexes co-exist as a larger complex of approximately 1000 kDa in the mitochondrial membrane. Following solubilization with a mild detergent, the cytochrome bc(1)-cytochrome c oxidase complex remains stable. It was analyzed using the techniques of gel filtration and blue native-polyacrylamide gel electrophoresis. Direct physical association of subunits of the cytochrome bc(1) complex with those of the cytochrome c oxidase complex was verified by co-immunoprecipitation analysis. Our data indicate that the cytochrome bc(1) complex is exclusively in association with the cytochrome c oxidase complex in yeast mitochondria. We term this complex the cytochrome bc(1)-cytochrome c oxidase supracomplex.