Activation of nuclear factor kappaB in colonic mucosa from patients with collagenous and ulcerative colitis

BACKGROUND AND AIMS

Expression of inducible nitric oxide synthase (iNOS) is greatly upregulated in the colonic mucosa of patients with collagenous and ulcerative colitis. As the transcription factor nuclear factor kappaB (NFkappaB) is a major inducer of iNOS gene expression, we compared activation and transcriptional activity of NFkappaB in colonic mucosal biopsies from these patients.

PATIENTS

Eight patients with collagenous colitis, six with relapsing ulcerative colitis, and eight with uninflamed bowel were studied.

METHODS

NFkappaB DNA binding activity was assessed by electrophoretic mobility shift assay and inhibitor of NFkappaB (IkappaB) kinase (IKK) activity by immunocomplex kinase assay. In vivo recruitment of NFkappaB to the iNOS promoter was determined by chromatin immunoprecipitation analysis and transcriptional activity by NFkappaB gene expression profiling arrays. Cells showing NFkappaB activation were identified by immunohistochemistry.

RESULTS

In collagenous and ulcerative colitis, as opposed to uninflamed bowel, IKKbeta activity and strong NFkappaB DNA binding gave rise to activation of identical NFkappaB subunits and recruitment of transcriptionally active p65 to the iNOS promoter. In collagenous colitis, activated NFkappaB was observed only in epithelial cells while up to 10% of lamina propria macrophages showed activation in ulcerative colitis.

CONCLUSIONS

In collagenous and ulcerative colitis, colonic mucosal NFkappaB is activated and recruited to the iNOS promoter in vivo via an IKKbeta mediated pathway. As collagenous colitis is not associated with tissue injury, these data challenge the prevailing view that activation of NFkappaB per se mediates tissue injury. Our results suggest that downstream inflammatory reactions leading to tissue damage originate in lamina propria immune cells, as increased NFkappaB activity in collagenous colitis was localised solely in epithelial cells, but present also in macrophages in ulcerative colitis.

Real-time myocardial contrast echocardiography for the detection of stress-induced myocardial ischemia. Comparison with 99mTc-sestamibi single photon emission computed tomography

BACKGROUND

Real-time contrast echocardiography (MCE) is a new promising technique for assessing myocardial perfusion. The purpose of this study was to test whether realtime MCE can be used to detect functionally significant coronary artery stenosis in patients with known or suspected coronary artery disease. Myocardial contrast echocardiographic studies were compared with nearly simultaneous 99mTc-sestamibi single photon emission computed tomography (SPECT) as a clinical standard reference to evaluate regional myocardial perfusion defects.

METHODS

Real-time MCE based on continuous infusion of Optison (8-10 ml/h) was performed in 66 patients during standard 99mTc-SPECT dipyridamole (0.56 mg/kg x 4 min) stress testing. Images were obtained in apical 4- and 2-chamber views, each divided into 6 segments. Tracer uptake and myocardial opacification were visually analyzed for each segment by two pairs of blinded observers and graded as normal, mildly reduced, severely reduced, or absent. In 792 myocardial segments, myocardial opacification by MCE was uninterpretable in 143 (18%) segments and tracer uptake by SPECT was not clearly defined in 92 (12%) segments. Interobserver variability for MCE was good with concordance rates of 83% (kappa=0.72) for rest- and 86% (kappa=0.76) for stress images. Overall concordance between MCE and SPECT was good (83%, kappa=0.63) at a segmental level. In the diagnosis of fixed and reversible defects, and of normal perfusion, concordance rates were 73, 65 and 83%, respectively. When analysis was performed at the regional level, we found comparable levels of concordance rates for LAD (83%, kappa=0.59), LCX (86%, kappa=0.64) and RCA (80%, kappa=0.68) perfusion territories.

CONCLUSIONS

These findings suggest that realtime MCE is a clinically acceptable method to evaluate myocardial perfusion defects during dipyridamole stress testing.

Therapie des adipösen Hypertonikers

There is a 50 % prevalence of obesity with arterial hypertension. This ratio can increase up to 80 %, depending on body mass index. Important pathogenetic origins are quantity of visceral body fat along with the activation of neuroendocrineum (sympathicus, renin-angiotensin system), an induction of insulin resistance with hyperinsulinemia, and a direct compression of the medulla by fat deposits in the kidneys, which results in hemodynamic changes and an increase in blood pressure. The primary aim is a reduction in weight by means of a balanced diet and life style modification, which can be augmented by weight reducing medication. Orlistat lowers blood pressure and body weight simultaneously, whereas sibutramine accomplishes this only under certain circumstances. Interestingly, blood pressure increases again over the course of 10 years following weight reducing surgical procedures, despite ongoing weight loss. Antihypertensive differential therapy should be focused on pathophysiology and concomitant and target organ disease. Thus ACE inhibitors (alternatively angiotensin receptor blockers), in combination with low dose diuretics, should be preferentially administered, followed by calcium antagonists. Beta blockers should be used if definite cardiac indications are present.

Intermittent flow of a collection of rigid frictional disks in a vertical pipe

We study the quasistatic flow of a collection of rigid frictional disks pushed upward (against the gravity) inside a narrow vertical pipe by a compliant mechanism. The contact dynamics method was used for the numerical simulations in combination with a friction law at disk-disk and wall-disk contacts characterized by discontinuous velocity weakening from a static threshold to a dynamic coefficient of friction. The material is sheared by the rolling of particles at the walls inducing a convective motion in the bulk. We observe a transition from constant flow to an intermittent flow when the driving velocity is reduced below a characteristic velocity that scales as k(-1/2) with the stiffness k of the pushing mechanism. The intermittent flow is composed of alternating phases of creep motion, where the pressure at the bottom of the granular column rises nonlinearly with time, and sudden slip, corresponding to a fast pressure drop. We show that the mean static pressure is correctly predicted by the Janssen model. The interplay between friction mobilization at the walls and structural changes in the bulk gives rise to a broad distribution of slip amplitudes characterized by a power law with an exponent approximately -1.7 that appears to be robust with respect to our system parameters.

Superiority of network motifs over optimal networks and an application to the revelation of gene network evolution

MOTIVATION

Estimating the network of regulative interactions between genes from gene expression measurements is a major challenge. Recently, we have shown that for gene networks of up to around 35 genes, optimal network models can be computed. However, even optimal gene network models will in general contain false edges, since the expression data will not unambiguously point to a single network.

RESULTS

In order to overcome this problem, we present a computational method to enumerate the most likely m networks and to extract a widely common subgraph (denoted as gene network motif) from these. We apply the method to bacterial gene expression data and extensively compare estimation results to knowledge. Our results reveal that gene network motifs are in significantly better agreement to biological knowledge than optimal network models. We also confirm this observation in a series of estimations using synthetic microarray data and compare estimations by our method with previous estimations for yeast. Furthermore, we use our method to estimate similarities and differences of the gene networks that regulate tryptophan metabolism in two related species and thereby demonstrate the analysis of gene network evolution.

AVAILABILITY

Commercial license negotiable with Gene Networks Inc. (cherkis@gene-networks.com)

CONTACT

sascha-ott@gmx.net

Free-energy landscape and the critical velocity of superfluid films

We briefly review some important properties of superfluid flow, especially the problem of critical velocity. We then present new numerical simulation results for a mesoscopic model of superfluids shedding light on the free-energy landscape, the critical velocity and the formation of vortices, which destroy the superflow when the velocity is high.

Expression and localisation of matrix metalloproteinases and their natural inhibitors in fistulae of patients with Crohn's disease

BACKGROUND

Fistulae are a troublesome complication of Crohn's disease but little is known of the final effector molecules responsible for matrix degradation. Although matrix metalloproteinases (MMPs) have been strongly implicated in tissue injury in Crohn's disease, their role in fistula formation is unknown.

AIM

To determine the expression pattern of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in fistulae of patients with Crohn's disease.

PATIENTS AND METHODS

Resected fistula specimens were obtained from patients with Crohn's disease (n = 11) and classified according to the predominant histological features-that is, acute versus chronic inflammation. Patients with fistulae due to other diseases (n = 9) and normal colon (n = 5) served as controls. MMP and TIMP protein expression was measured by single or double labelled immunohistochemistry, and mRNA expression by in situ hybridisation. MMP activity was measured by gelatin zymography.

RESULTS

Compared with normal colon, strong MMP-3 expression was consistently observed in fistulae in Crohn's disease, irrespective of the stage of inflammatory activity. MMP-3 transcripts and protein were localised in large mononuclear cells and fibroblasts. MMP-9 transcripts and protein were expressed in granulocytes and only in fistulae with acute inflammation. Staining for MMP-1 and MMP-7 was weak and negative for MMP-10, whereas MMP-2 was equally expressed in normal colon and fistulae. TIMP-1, TIMP-2, and TIMP-3 expression was low in all samples. Similar expression patterns were found in fistulae of the disease control group. Fistulae also expressed active MMP-2 and MMP-9, as measured by gelatin zymography.

CONCLUSION

MMP-3 and MMP-9 are markedly upregulated in intestinal fistulae and may contribute to fistula formation through degradation of the extracellular matrix, irrespective of the underlying disease process.

ACE-inhibition is superior to endothelin A receptor blockade in preventing abnormal capillary supply and fibrosis of the heart in experimental diabetes

AIMS/HYPOTHESIS

There is little information whether cardiac capillary supply is deranged in diabetes. Hyperglycaemia is a potent stimulus for endothelin-1 (ET-1) production. We therefore hypothesised that increased ET-1 production in Streptozotocin-induced Type 1 diabetes causes abnormalities of cardiac capillaries and the aorta. To this end we compared the effects of an ET receptor A blocker (ETA-RB) with that of an ACE-inhibitor (ACE-i) or their combination in rats with Streptozotocin (STZ) diabetes.

METHODS

Sprague Dawley rats were injected with 65 mg STZ i.v. and subsequently developed diabetes. Rats were left untreated or received daily either the ACE-i Trandolapril, the ETA-RB Darusentan or a combination of both. After 6 months the experiment was terminated and the heart and the aorta were investigated using quantitative morphological techniques.

RESULTS

ACE-i but not ETA-RB lowered blood pressure in STZ Type 1 diabetic rats. Capillary length density was lower in untreated STZ diabetic rats (2932+/-128 mm/mm3) compared to non-diabetic control rats (3410+/-252 mm/mm3). Treatment with ACE-i (3568+/-431 mm/mm3), but not with ETA-RB (2893+/-192 mm/mm3), prevented the decrease in capillary supply. Volume density of the myocardial interstitium was higher in untreated STZ diabetic rats (0.86+/-0.04%) compared to non-diabetic control rats (0.36+/-0.06%). In all three intervention groups the values were lower (ACE-i: 0.53+/-0.05%, ETA-RB: 0.7+/-0.08% and combination: 0.69+/-0.1).

CONCLUSION/INTERPRETATION

Our study identifies a capillary defect of the heart in STZ diabetes, i.e. decreased capillary supply. This abnormality was reversed by ACE-i, but not by ETA-R blockade. A similar trend, although not complete normalisation, was seen in cardiac fibrosis.

Immune hemolysis-serological and clinical aspects

The differential diagnosis of anemia must consider immune hemolytic anemias as a frequent cause. Whereas detection of anti-red blood cell (RBC) alloantibodies frequently induced by immunogenic stimuli (transfusion, pregnancy) is performed by routine serology, diagnosing autoimmune hemolytic anemias or drug-induced hemolytic anemias remains a challenge, usually requiring close collaboration of a number of disciplines. Positive direct antiglobulin test (Coombs' test) represents a central criterion in diagnosing immune hemolytic anemias, leading to further detailed analyses. The most-severe type of immune-mediated hemolysis is acute intravascular hemolysis after ABO incompatible RBC transfusion. This review highlights underlying biochemical aspects, immunohematological diagnostics, and the clinical relevance of RBC allo- and autoantibodies, including paroxysmal nocturnal hemoglobinemia and drug-induced hemolysis. Finally, current and partly experimental therapeutic strategies of immune hemolytic anemias are summarized.

Comparison of immunoglobulin heavy chain rearrangements between peripheral and glandular B cells in a patient with primary Sjögren's syndrome

Myoepithelial sialadenitis (MESA) of the major salivary glands is a characteristic feature of primary Sjögren's syndrome (pSS). To delineate systemic and organ-specific influences on B cells in a patient with pSS and benign MESA, individual B cells were simultaneously obtained from the peripheral blood and inflamed parotid gland. Immunoglobulin variable heavy chain (VH) rearrangements in single sorted CD19+ B cells were subsequently amplified, sequenced and analysed. Despite the presence of two clonal expansions using VH1-08 and VH2-70 segments, respectively, the majority of glandular B cells were polyclonal, resembling the VH gene usage and mutational pattern of the corresponding blood population. However, striking differences were observed in the proportion of cells expressing mutated VH rearrangements (blood, 28.9% versus parotid, 80.4%; P < 0.0001). Moreover, the glandular productive VH rearrangements differed significantly from their blood counterparts by a higher mutational frequency (P < 0.0001), shorter CDR3 lengths (P = 0.001) and a less frequent usage of JH6 (P = 0.0292), indicating an accumulation of memory B cells in the inflamed parotid. Thus, both preferential influx/homing of memory B cells and local proliferation may contribute to the pattern of benign MESA in pSS. Notably, one of the glandular clonal rearrangements (using VH1-08) was also detected in the patient's peripheral repertoire.

Effect of micronized progesterone on bone turnover in postmenopausal women on estrogen replacement therapy

PURPOSE

To determine whether daily oral micronized progesterone affects bone turnover, as estimated by serum and urine biochemical markers, in postmenopausal women on long-term estrogen replacement therapy (ERT).

METHODS

We recruited 14 women aged 65 or older to participate in a 9-week trial with micronized progesterone. Each woman had undergone a hysterectomy and was on unopposed ERT at time of study entry. Women received micronized progesterone 100 mg twice daily in the first week and then received 200 mg twice daily in weeks 2-9. We measured markers of bone turnover in serum and urine collected at baseline and at 3 weeks, 6 weeks, and 9 weeks on treatment. Markers of bone formation were serum bone alkaline phosphatase (BAP), N-terminal procollagen peptides (PINP), and osteocalcin (OC). Markers of bone resorption were urinary cross-linked N-terminal and C-terminal telopeptides of type I collagen. In addition, we measured serum progesterone, estradiol and sex hormone binding globulin, triglycerides, total cholesterol, and high-density lipoprotein (HDL)-cholesterol levels at baseline and at 9 weeks on treatment.

RESULTS

Mean serum progesterone levels increased from 1.6 +/- 1.1 to 15.2 +/- 3.9 ng/mL, which was within the luteal phase range (3-25 ng/mL). Crosslinked C-telopeptides of type I collagen and osteocalcin increased significantly (p < 0.05) with progesterone treatment, however, other bone markers did not change. Estradiol, estrone, and SHBG levels did not change with treatment. High-density lipoprotein-cholesterol levels decreased 19% (p < 0.001) at 9 weeks on treatment compared to baseline but total and low-density lipoprotein (LDL) cholesterol and triglycerides did not change with treatment.

CONCLUSION

In postmenopausal women on long-term estrogen replacement therapy, micronized progesterone (400 mg/d) increased one marker each of bone resorption and bone formation. Other sensitive markers of bone turnover did not change with treatment. Further, micronized progesterone decreased HDL-cholesterol in these women. Our data do not support a beneficial effect of micronized progesterone on bone or cardiovascular risk factors in postmenopausal women.

Non-overt disseminated intravascular coagulation in patients during treatment with antithymocyte globulin for unrelated allogeneic hematopoietic stem cell transplantation

We assessed the effect of rabbit antithymocyte globulin manufactured by Fresenius (ATG-F) on the hemostatic system in patients (n=12) with various hematological malignancies undergoing hematopoietic stem cell transplantation (HSCT) from HLA-matched unrelated donors. For this purpose, we monitored different parameters of coagulation before, during and after the administration of ATG-F. As a control group, we recruited patients (n=10) undergoing HSCT from their HLA-identical siblings who did not receive ATG-F as part of their preparative regimens. At 24 and 48 h after ATG-F treatment had been initiated, we found a temporary rise in D-Dimer, tissue factor, soluble thrombomodulin and thrombin-antithrombin III complex levels and a significant decrease of platelet counts in patients treated with ATG-F as compared to the control group. No differences between the two groups could be detected with regard to global coagulation tests as well as the incidence of bleeding manifestations, thromboembolic complications or the development of vascular-occlusive-disease of the liver. This temporary state of a stressed but compensated coagulation system under ATG-F therapy can be addressed as nonovert disseminated intravascular coagulation (DIC). The effect was independent from the different conditioning regimens and eased off after cessation of ATG-F. We conclude that ATG-F can induce nonovert DIC in patients receiving antithymocyte globulin as part of their conditioning regimen for HSCT.

Myocardial contrast echocardiography yields best accuracy using quantitative analysis of digital data from pulse inversion technique: comparison with second harmonic imaging and harmonic power Doppler during simultaneous dipyridamole stress SPECT studies

AIMS

This prospective study assesses the (1) feasibility of quantifying ultrasound myocardial perfusion studies based on the densitometric analysis of digital data and the (2) comparison of pulse inversion, second harmonic and harmonic power Doppler modalities with SPECT.

METHODS AND RESULTS

Twenty-three patients with suspected ischaemic heart disease had i.v. injections of Tc-Sestamibi and Optison during a dipyridamole stress test for echocardiography in pulse inversion, second harmonic and harmonic power Doppler mode. Analysis was (a) visual by scoring and (b) quantitative by densitometry of digital data for background subtracted myocardial opacification (a.u.) and normalized contrast effect (%). In the nine control patients, myocardial opacification at stress was greater (P< or =0.002) than in the pathologic group (5. +/- 3.3 vs 2.6 +/- 2.5 a.u. in pulse inversion, 5.4 +/- 2.1 vs 2.4 +/- 1.8 in second harmonic and 7.1 +/- 3.7 vs 4.9 +/- 3.7 a.u. in harmonic power Doppler). In the pathologic group, normalized contrast effect decreased significantly during stress (23.7 +/- 18.8 to 11.3 +/- 10.8%, P<0.003) only in pulse inversion. Kappa values for patient based diagnostic agreement with SPECT were 0.75 by pulse inversion, 0.62 by second harmonic and 0.52 by harmonic power Doppler for quantitative analysis, and 0.51, 0.37 and 0.35 respectively, for visual assessment.

CONCLUSION

Myocardial contrast echocardiography should be analysed using densitometry of digital data. The new technique pulse inversion demonstrates best agreement with SPECT data.

[Pitfalls in hypertension management--misjudgements in diagnosis and therapy]

HISTORY AND CLINICAL FINDINGS

A 71-year-old woman with arterial hypertension, diabetes type 2, peripheral vascular disease and Sjögren's syndrome presented with progressive weakness, dizziness, insomnia, palpitations and headache. These symptoms did not improve by changing her antihypertensive treatment. The patient's general condition was quite normal and there were no signs of acute or chronic cardiopulmonary decompensation.

INVESTIGATIONS

Besides arterial hypertension, she also had an elevated body mass index, dyslipoproteinemia, microalbuminuria, diabetic metabolism, left ventricular hypertrophy with signs of an abnormal diastolic cardiac function as well as atherosclerotic lesions (in both carotid arteries) which were identified as the patient's cardiovascular risk factors. Ambulant blood pressure monitoring revealed decreasing BP values for a period of 5 hrs after drug intake but, subsequently, severe hypertensive values (up to 220 mmHg systolic) without adequate decrease at night. Moreover, a hyperkinetic regulation of her circulation was demonstrated by hemodynamic monitoring and assessment of the autonomic nervous system.

TREATMENT

By changing drug treatment, i. e. administration of an anti-adrenergic calcium antagonist of the non-dihydropyridine type combined with an ACE inhibitor and a diuretic, respectively, (both given in fixed combinations) led to the normalization of the blood pressure and pulse rate as well as an improvement of the patient's condition.

CONCLUSIONS

This case emphasizes the importance of ambulant blood pressure monitoring and an assessment of the heart rate in individually adapted antihypertensive drug therapy. The application of metabolically neutral fixed drug combinations with special regard to associated diseases, organ protection and the patient's compliance resulted in normotensive blood pressure values and an improvement of the quality of life.

Refugee dynamics: Angolans in Zambia 1966 to 1972

"The following study of Angolan refugees in Zambia examines the decision-making dynamics of refugee movements, documents a case of extensive self-settlement, describes the background to the refugee movement, and briefly compares the welfare of self-settling refugees and those who are in government schemes."

Dynamic rearrangements and packing regimes in randomly deposited two-dimensional granular beds

We study the structural properties of two-dimensional granular packings prepared by random deposition from a source line. We consider a class of random ballistic deposition models based on single-particle relaxation rules controlled by a critical angle, and we show that these local rules can be formulated as rolling friction in the framework of dynamic methods for the simulation of granular materials. We find that a packing prepared by random deposition models is generically unstable, and undergoes dynamic rearrangements. As a result, the dynamic method leads systematically to a higher solid fraction than the geometrical model for the same critical angle. We characterize the structure of the packings generated by both methods in terms of solid fraction, contact connectivity, and anisotropy. Our analysis provides evidence for four packing regimes as a function of solid fraction, the mechanisms of packing growth being different in each regime.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

Neurogenesis in the central olfactory pathway of the adult shore crab Carcinus maenas is controlled by sensory afferents

The number of olfactory projection neurons (OPNs) in the brain of the juvenile and adult shore crab Carcinus maenas continues to increase during the life of the animal. In vivo labeling of adult crabs with the proliferation marker bromodeoxyuridine (BrdU) revealed a group of proliferating neuronal precursor cells in the lateral soma clusters (LCs) and in the soma clusters of the hemiellipsoid bodies (HBCs). The LCs contain the cell bodies of the olfactory projection neurons and the HBCs house the cell bodies to which the OPNs project. The aim of the present study was to examine whether the input from primary olfactory afferents has any influence on the rate of proliferation and survival of the neuronal precursors in the central olfactory pathways of C. maenas. Different sets of experiments involving BrdU injection and its immunocytochemical detection combined with unilateral amputation of the antennule that houses the olfactory organ were carried out. Our results show that the missing olfactory sensory input affects the rate of proliferation and the survival of postmitotic cells in the LC and in the HBC compared with control animals. The effect on the survival of postmitotic cells tested by BrdU injection followed by unilateral ablation is lateralized. Proliferation of neuronal precursor cells tested by the reversed experimental order was drastically impaired bilaterally. We conclude that the olfactory sensory input is necessary for a normal rate of proliferation of neuronal precursors and the survival of their progeny in the LC and in the HBC of C. maenas.

Features of mono- and multinucleated bone resorbing cells of the zebrafish Danio rerio and their contribution to skeletal development, remodeling, and growth

To provide basic data about bone resorbing cells in the skeleton during the life cycle of Danio rerio, larvae, juveniles, and adults (divided into six age groups) were studied by histological procedures and by demonstration of the osteoclast marker enzyme tartrate-resistant acid phosphatase (TRAP). Special attention was paid to the lower jaw, which is a standard element for fish bone studies. The presence of osteoclasts at endosteal surfaces of growing bones of all animals older than 20 days reveals that resorption is an important part of zebrafish skeletal development. The first bone-resorbing cells to form are mononucleated. They appear in 20-day-old animals concurrently in the craniofacial skeleton and vertebral column. Mononucleated osteoclasts are predominant in juveniles. Regional differences characterize the appearance of osteoclasts; at thin skeletal elements (neural arches, nasal) mononucleated osteoclasts are predominant even in adults. Multinucleated bone-resorbing cells were first observed in 40-day-old animals and are the predominant osteoclast type of adults. Both mono- and multinucleated osteoclasts contribute to allometric bone growth but multinucleated osteoclasts are also involved in lacunar bone resorption and repeated bone remodeling. Resorption of the dentary follows the pattern described above (mononucleated osteoclasts precede multinucleated cells) and includes the partial removal of Meckel's cartilage. Bone marrow spaces created by resorption are usually filled with adipose tissue. In conclusion, bone resorption is primarily subjected to the demands of growth, the appearance of mono- and multinucleated osteoclasts is site- and age-related, and bone remodeling occurs. The results are discussed in relation to findings in other teleosts and in mammals.

Immunoglobulin Vlambda light chain gene usage in patients with Sjögren's syndrome

OBJECTIVE

To determine whether patients with Sjögren's syndrome (SS) have abnormalities in Ig Vlambda and Jlambda gene usage, differences in somatic hypermutation, defects in selection, or indications for perturbations of B cell maturation.

METHODS

Individual peripheral B cells from SS patients were analyzed for their Vlambda gene usage by single-cell polymerase chain reaction amplification of genomic DNA and compared with those from normal controls.

RESULTS

Molecular differences from controls in Vlambda-Jlambda recombination were identified that were reflected by findings in the nonproductive Vlambda repertoire of the patients, including enhanced rearrangement of Vlambda10A and Jlambda2/3 gene segments. In addition, a number of abnormalities in the productive repertoire were identified, indicating disordered selection. A greater usage of 4 Vlambda genes (2A2, 2B2, 2C, and 7A), representing 56% of all productive Vlambda rearrangements, was observed, suggesting positive selection of these genes. Overutilization of Jlambda2/3 and underutilization of Jlambda7 in both nonproductive and productive Vlambda rearrangements of SS patients compared with controls suggested decreased receptor editing in SS. The mutational frequency did not differ from that in controls, and positive selection of mutations into the productive V gene repertoire was found, similar to that in controls, although mutational targeting toward RGYW/WRCY motifs, typically found in controls, was not found in SS patients.

CONCLUSION

Disturbed regulation of B cell maturation with abnormal selection, defects in editing Ig receptors, and abnormal mutational targeting may contribute to the emergence of autoimmunity in SS.

Effect of norethindrone acetate on hormone levels and markers of bone turnover in estrogen-treated postmenopausal women

There is controversy concerning the effects of progestins on bone. Norethindrone acetate (NETA) is synthetic progesterone that also has estrogenic and androgenic effects. We tested its effects on hormone levels, lipids and biochemical markers of bone turnover in postmenopausal women who were on estrogen replacement therapy. Women were treated with NETA, 5 mg/d for 9 weeks. Estrogenic effects included a marked lowering of follicle stimulating hormone and luteinizing hormone. Androgenic effects included a decrease in sex hormone binding globulin and HDL cholesterol. Bone turnover showed inconsistent responses. Among markers of bone formation, bone specific alkaline phosphatase decreased significantly by 23% while procollagen peptides and osteocalcin showed a non-significant increase. The marker of bone resorption, N-telopeptide crosslinks of collagen, decreased by 19% at 6 weeks. These results indicate that NETA does not have a potent short-term anabolic effect on bone but does have effects that are likely to be mediated through the estrogen and androgen receptors.

Roughness of crack interfaces in two-dimensional beam lattices

The roughness of crack interfaces is reported in quasistatic fracture, using an elastic network of beams with random breaking thresholds. For strong disorders we obtain zeta = 0.86(3) for the roughness exponent, a result which is very different from the minimum energy surface exponent, i.e., zeta = 2 / 3. A crossover to lower values is observed as the disorder is reduced, the exponent in this regime being strongly dependent on the disorder.

Is the "candy-wrapper" effect of (32)P radioactive beta-emitting stents due to remodeling or neointimal hyperplasia? Insights from intravascular ultrasound

A recognized limitation of radioactive stents is the development of restenosis at the stent edges, known as the "candy-wrapper" effect. The mechanisms of this effect remain incompletely understood and controversial. The aim of this study is to assess the effect of endovascular irradiation on neointima formation and vascular remodeling. (32)P Palmaz-Schatz stents (1.5-4 microCi) were implanted in 11 patients with restenosis after previous percutaneous transluminal coronary angioplasty (PTCA). Intravascular ultrasound (IVUS) images of target sites and adjunct vessel segments were acquired both during intervention and after 6 months. The angiographic restenosis rate was 54%, and the MLD decreased from 2.21 +/- 0.6 mm to 1.38 +/- 0.4 mm at follow-up (P < 0.01). IVUS analysis demonstrated that late lumen loss was the result of neointimal tissue proliferation, which was nonuniformly distributed and exaggerated at both the central articulation and the distal stent edges. Negative remodeling did not contribute to restenosis. In contrast, we found a linear relationship between increase of area stenosis and a positive remodeling index (r = 0.84, P < 0.0001). Restenosis after implantation of (32)P Palmaz-Schatz stents was mainly the result of neointimal tissue proliferation which tended to be nonuniformly distributed in the stent articulation and edges. Negative remodeling or stent recoil was not observed. Cathet Cardiovasc Intervent 2001;54:41-48.

Unicellular cyanobacteria fix N2 in the subtropical North Pacific Ocean

Fixed nitrogen (N) often limits the growth of organisms in terrestrial and aquatic biomes, and N availability has been important in controlling the CO2 balance of modern and ancient oceans. The fixation of atmospheric dinitrogen gas (N2) to ammonia is catalysed by nitrogenase and provides a fixed N for N-limited environments. The filamentous cyanobacterium Trichodesmium has been assumed to be the predominant oceanic N2-fixing microorganism since the discovery of N2 fixation in Trichodesmium in 1961 (ref. 6). Attention has recently focused on oceanic N2 fixation because nitrogen availability is generally limiting in many oceans, and attempts to constrain the global atmosphere-ocean fluxes of CO2 are based on basin-scale N balances. Biogeochemical studies and models have suggested that total N2-fixation rates may be substantially greater than previously believed but cannot be reconciled with observed Trichodesmium abundances. It is curious that there are so few known N2-fixing microorganisms in oligotrophic oceans when it is clearly ecologically advantageous. Here we show that there are unicellular cyanobacteria in the open ocean that are expressing nitrogenase, and are abundant enough to potentially have a significant role in N dynamics.

High-dose stabilized chlorite matrix WF10 prolongs cardiac xenograft survival in the hamster-to-rat model without inducing ultrastructural or biochemical signs of cardiotoxicity

WF10 is a stabilized chlorite matrix with immunosuppressive effects. In vitro studies have demonstrated its ability to suppress T cells and delay or abolish antigen presentation. Hence, WF10 may prove useful to prolong graft survival after transplantation. In this study, we evaluated the use of high dose WF10 as a single drug regimen in the hamster-to-rat xenotransplantation model and searched for possible cardiotoxic side effects. WF10 prolonged cardiac xenograft survival, but did not induce tolerence or inhibit pathological signs of acute rejection. Hamsters from the donor population, receiving high dose WF10 for 5 days, were compared with a matched control group. Ultrastructural examination of cardiac tissue as well as biochemical analysis of the cardiac enzymes troponin I, myoglobin and MB isoenzyme of creatine kinase showed no signs of damage. Thus, while prolonging graft survival, high dose WF10 seems to be non-cardiotoxic and as such should not contribute to the differential diagnosis of acute graft failure.

Heat capacity of protein folding

We construct a Hamiltonian for a single domain protein where the contact enthalpy and the chain entropy decrease linearly with the number of native contacts. The hydration effect upon protein unfolding is included by modeling water as ideal dipoles that are ordered around the unfolded surfaces, where the influence of these surfaces, covered with an "ice-like" shell of water, is represented by an effective field that directs the water dipoles. An intermolecular pair interaction between water molecules is also introduced. The heat capacity of the model exhibits, the common feature of small globular proteins, two peaks corresponding to cold and warm unfolding, respectively. By introducing ad hoc vibrational modes, we obtain quantitatively good accordance with experiments on myoglobin.

Antioxidant effects of phenolic rye (Secale cereale L.) extracts, monomeric hydroxycinnamates, and ferulic acid dehydrodimers on human low-density lipoproteins

Dietary antioxidants that protect low-density lipoprotein (LDL) from oxidation may help to prevent atherosclerosis and coronary heart disease. The antioxidant activities of purified monomeric and dimeric hydroxycinnamates and of phenolic extracts from rye (whole grain, bran, and flour) were investigated using an in vitro copper-catalyzed human LDL oxidation assay. The most abundant ferulic acid dehydrodimer (diFA) found in rye, 8-O-4-diFA, was a slightly better antioxidant than ferulic acid and p-coumaric acid. The antioxidant activity of the 8-5-diFA was comparable to that of ferulic acid, but neither 5-5-diFA nor 8-5-benzofuran-diFA inhibited LDL oxidation when added at 10-40 microM. The antioxidant activity of the monomeric hydroxycinnamates decreased in the following order: caffeic acid > sinapic acid > ferulic acid > p-coumaric acid. The antioxidant activity of rye extracts was significantly correlated with their total content of monomeric and dimeric hydroxycinnamates, and the rye bran extract was the most potent. The data suggest that especially rye bran provides a source of dietary phenolic antioxidants that may have potential health effects.

Differential value of adenosine myocardial contrast echocardiography and dobutamine stress echocardiography in evaluating functional significance of coronary artery stenosis in a porcine model

AIM

Myocardial contrast echocardiography (MCE) during adenosine induced hyperemia is an experimental method that detects flow limiting coronary artery stenosis by visualizing myocardial perfusion defects. Noninvasive detection of flow limiting coronary artery stenosis in clinical routine is a frequent domaine of dobutamine stress echocardiography (DSE) visualizing ischemia related regional wall motion abnormalities. This study investigated the values of adenosine MCE and DSE in the detection of functionally significant coronary artery stenosis in an experimental open chest pig model.

METHODS

A total of 28 proximal LAD stenoses were instrumented in 12 animals. Reduction of coronary blood flow reserve (delta CFR [%] ) was calculated as a marker of functional significance of coronary artery stenosis (mild to moderate stenosis: delta CFR < or = 50%; severe stenosis: delta CFR > 50%). Fractional area shortening (FAS) and wall thickening (WT) were calculated to evaluate regional wall motion. Peak myocardial contrast intensities (PCI) were measured following aortic root injections of Levovist' to detect mocardial perfusion defects.

RESULTS

As a group, severe stenosis significantly reduced wall motion response to dobutamine (delta FAS: 12.0 +/- 3.0%, vs. 20 +/- 3.0% without stenosis, p < 0.05; delta WT: 2.2 +/- 0.9 mm vs. 0.0 +/- 0.8 mm without stenosis, p < 0.05) and diminished myocardial opacification during hyperemia (PCI: 59 +/- 8 units vs. 143 +/- 16 units without stenosis, p < 0.05). Mild to moderate stenosis did not influence wall motion but reduced myocardial opacification (PCI 89 +/- 14 units vs. 143 +/- 16 units). PCI correlated more closely with alterations in CFR (r = -0.7, p < 0.0001) than did FAS (r = -0.5, p < 0.002) or WT (r = -0.2, p = 0.3).

CONCLUSION

Adenosine myocardial contrast echocardiography detects flow limiting coronary artery stenosis and compares favorably to regional wall motion analysis during dobutamine infusion.

Exploring the minimal substrate requirements for trans-cleavage by RNase P holoenzymes from Escherichia coli and Bacillus subtilis

We analysed the processing of small bipartite model substrates by Escherichia coli and Bacillus subtilis RNase P and corresponding hybrid enzymes. We demonstrate specific trans-cleavage of a model substrate with a 4 bp stem and a 1 nucleotide (nt) 5' flank, representing to date the smallest mimic of a natural RNase P substrate that could be processed in trans at the canonical RNase P cleavage site. Processing efficiencies decreased up to 5000-fold when the 5' flank was shortened from 3 to 1 nt. Reduction of the 5' flank to 1 nt was more deleterious than reducing the stem from 7 to 4 bp, although the 4 bp duplex formed only transiently, in contrast to the stable 7 bp duplex. These results indicate that the crucial contribution of nt -2 in the single-stranded 5' flank to productive interaction is a general feature of A- and B-type bacterial RNase P enzymes. We also showed that an Rp-phosphorothioate modification at nt -2 interferes with processing. Bacterial RNase P holoenzymes are also capable of cleaving single-stranded RNA oligonucleotides as short as 5 nt, yielding RNase P-specific 5'-phosphate and 3'-OH termini, with measured turnover rates of up to 0.7 min-1. All cleavage sites were at least 2 nt away from the 5' and 3' ends of the oligonucleotides. Some cleavage site preferences were observed dependent on the identity of the RNase P RNA subunit.

Thermodynamical implications of a protein model with water interactions

We refine a protein model that reproduces fundamental aspects of protein thermodynamics. The model exhibits two transitions, hot and cold unfolding. The number of relevant parameters is reduced to three: (1) binding energy of folding relative to the orientational energy of bound water, (2) ratio of degrees of freedom between the folded and unfolded protein chain, and (3) the number of water molecules that can access the hydrophobic parts of the protein interior upon unfolding. By increasing the number of water molecules in the model, the separation between the two peaks in the heat capacity curve comes closer, which is more consistent with experimental data. In the end we show that if we, as a speculative assumption, assign only two distinct energy levels for the bound water molecules, better correspondence with experiments can be obtained.

Distinguishing fractional and white noise in one and two dimensions

We discuss the link between uncorrelated noise and the Hurst exponent for one- and two-dimensional interfaces. We show that long range correlations cannot be observed using one-dimensional cuts through two-dimensional self-affine surfaces whose height distributions are characterized by a Hurst exponent H lower than -1/2. In this domain, fractional and white noise are not distinguishable. A method analyzing the correlations in two dimensions is necessary. For H>-1/2, a crossover regime leads to an systematic overestimate of the Hurst exponent.

Enhanced mutational activity and disturbed selection of mutations in V(H) gene rearrangements in a patient with systemic lupus erythematosus

To determine the impact of somatic hypermutation and selective influences on the V(H) gene repertoire in SLE, the mutational frequency and pattern of mutations in nonproductively and productively rearranged V(H) genes obtained from genomic DNA of individual CD19+ B cells were analyzed in a patient with SLE. The mutational frequencies of nonproductive (6.54 x 10(-2)) as well as of productive (4.38 x 10(-2)) V(H) rearrangements were significantly higher in the SLE patient than in normal controls (3.8 x 10(-2), p<0.001 and 3.3 x 10(-2); p<0.001, respectively). Analysis of nonproductive rearrangements documented only minor abnormalities of the targeting of the mutator in the SLE patient. The majority of "mutational hot spots", although different than in normals, appeared in the CDRs and an increased frequency of mutations in RGYW/WRCY sequences was observed. Moreover, no biases in base pair changes were found in the nonproductive repertoire. In contrast, there was a selection against A and T mutations and towards G mutations within the productive repertoire. Importantly, there were no significant differences in the R/S ratios of mutations within the FRs between the nonproductive and productive repertoire consistent with abnormalities in elimination of B cells expressing V(H) genes with these mutations. The result of this abnormality was a significantly higher R/S ratio of the V(H)genes in the productive repertoire of the SLE patient compared to normals (p<0.05). These data indicate that the mutational machinery was markedly enhanced in this SLE patient but exhibited nearly normal targeting, whereas selective influences were abnormal. These findings suggest that both enhanced mutational activity and disturbances in selection may have played a role in the emergence of autoreactivity in this SLE patient.

Echocardiographic quantification of left ventricular asynergy in coronary artery disease with Fourier phase imaging

BACKGROUND

Visual evaluation of wall motion is subjective and may be difficult in patients with impaired left ventricular function. Current algorithms used to analyze wall motion usually neglect motion asynchrony that may be profoundly altered in coronary artery disease. This study was to investigate whether the extent of left ventricular asynergy can be used to quantify the severity of regional myocardial dysfunction by the use of Fourier phase imaging.

METHODS

Echocardiographic cine loops of 21 patients with ischemic cardiomyopathy (EF < or = 40%) were mathematically transformed using a first-harmonic Fourier algorithm displaying the sequence of wall motion as phase angles in parametric images and regional phase histograms. Segmental fractional area shortening (FAC) and qualitative assessment of regional wall motion based on visual inspection served as reference method.

RESULTS

There was an inverse linear relationship between FAC and phase angles (r = -0.75, p < 0.01). Normal endocardial motion yielded low phase angles (mean 16 +/- 15 degrees SD). With an increase in wall motion abnormalities, phase angles were progressively delayed by 56 +/- 38 degrees in hypokinetic, by 88 +/- 38 degrees in akinetic, and by 143 +/- 33 degrees (p < 0.001) in dyskinetic segments.

CONCLUSIONS

These results demonstrate that left ventricular asynchrony is an indicator of regional myocardial dysfunction in coronary artery disease. Echocardiographic Fourier phase imaging can be used to quantify wall motion displaying contraction sequence in a simple and objective format.

Correlation between processing efficiency for ribonuclease P minimal substrates and conformation of the nucleotide -1 at the cleavage position

It is demonstrated that acceptor stem duplexes derived from native tRNAs which contain a three-nucleotide extension at the 5'-terminus of mature tRNA are minimal substrates for ribonuclease P from both Escherichia coli and Bacillus subtilis. Variants with a cytidine at position -1 are most efficiently processed whereas the G -1 variant represents a comparatively poor substrate. An A -1 acceptor stem variant is a slightly better substrate than the G -1 variant though generally distinctly less efficient than the C -1 duplex. This is in qualitative agreement with the frequency of the occurrence of the corresponding nucleotides at position -1 in natural substrates, which is highest for pyrimidines and least for G. NMR analyses of the corresponding acceptor stems reveal that the conformation of the nucleotides at position -1 correlates with the substrate preferences of Ribonuclease P: Whereas C -1 adopts a conformation characterized by a glycosidic angle in the anti range (close to high-anti), the G -1 is clearly in syn conformation, and that of A -1 is intermediate between high-anti and syn. The riboses of nucleotides -1 are in all cases predominantly 2'-endo puckered.

Prognostic value of Doppler echocardiographic mitral inflow patterns: implications for risk stratification in patients with chronic congestive heart failure

OBJECTIVES

This prospective study tested whether transmitral flow patterns add incremental value to peak oxygen consumption (VO2) in determining the prognosis of patients with chronic congestive heart failure (CHF) and systolic dysfunction.

BACKGROUND

Peak VO2 is an objective marker of functional capacity and is routinely used as a criterion to identify heart transplant candidates. Diastolic dysfunction limits functional capacity, but its prognostic importance relative to that of peak VO2 is unknown.

METHODS

Peak VO2 and mitral inflow velocities were prospectively measured in 311 consecutive patients (mean age 54 years, 84% male) with impaired left ventricular function (ejection fraction <40%; 88 patients with ischemic and 223 with dilated cardiomyopathy) who were evaluated for heart transplant candidacy.

RESULTS

During a mean follow-up period of 512 +/- 314 days, 65 patients died and 43 patients underwent heart transplantation. Diastolic filling patterns, peak VO2 and left ventricular end-diastolic diameters were independent predictors of cardiac mortality. In patients with peak VO2 < or = 14 ml/min per kg body weight, the outcome was markedly poorer in the presence of restrictive filling patterns as compared with their absence (two-year survival rate 52% vs. 80%). Similarly, despite peak VO2 levels >14 ml/min per kg, the outcome was less favorable in the presence of restrictive filling patterns (two-year survival rate 80% vs. 94%). A risk-stratification model based on the identified independent noninvasive predictors separated groups into those with high (93%), intermediate (65%) and low (39%) two-year survival rates.

CONCLUSIONS

Transmitral flow patterns add incremental value to peak VO2 in determining the prognosis of patients with CHF and impaired systolic function.

Immunoglobulin Vkappa light chain gene analysis in patients with Sjögren's syndrome

OBJECTIVE

Patients with Sjögren's syndrome (SS) have characteristic lymphocytic infiltration of the salivary glands with a previously reported predominance of Vkappa-bearing B cells and produce a variety of autoantibodies, indicating that there is a humoral autoimmune component in this syndrome. This study was undertaken to determine whether there are primary deviations of immunoglobulin V gene usage, differences in somatic hypermutation, defects of selection, or indications for perturbances of B cell maturation in SS.

METHODS

Individual peripheral B cells from patients with SS were analyzed for their Ig V gene usage, and the findings were compared with results in normal controls.

RESULTS

Molecular differences, as reflected by findings in the nonproductive Vkappa repertoire of the patients, were identified by an enhanced usage of Jkappa2 gene segments and a lack of mutational targeting toward RGYW/WRCY sequences compared with controls. A greater usage of Vkappa1 family members and a reduced frequency of Vkappa3 gene segments in the productive repertoire suggested differences in selection, possibly driven by antigen. Overall positive selection for mutations, especially for replacements in the complementarity-determining region and for mutations in RGYW/WRCY, similar to that found in controls, was detected.

CONCLUSION

Disturbances of strictly regulated B cell maturation, during early B cell development as indicated by prominent Jkappa2 gene usage and during germinal center reactions as indicated by a lack of targeting of the hypermutation mechanism, might contribute to the emergence of autoimmunity in SS.

The growth hormone-releasing hormone receptor: desensitisation following short-term agonist exposure

We have investigated the effect of short-term preexposure of growth hormone-releasing hormone (GHRH) on the subsequent response to GHRH in a baby hamster kidney (BHK) cell line expressing the human GHRH receptor and in primary rat pituitary cells. In the BHK cells the receptor was rapidly desensitised in a homologous fashion. Preexposure with agents directly stimulating the cAMP pathway like forskolin and db-cAMP had no effect. In rat pituitary cells we also observed a rapid desensitisation of the GHRH response in an apparently homologous fashion. In both systems the desensitisation was dose-dependent with no change in the potency of the hormone in a subsequent stimulation, only the efficacy was decreased. In the rat pituitary cell, the response measured as growth hormone release was more sensitive to the agonist-induced desensitisation than the cAMP response. No indication of depletion of growth hormone (GH) stores was seen. In rat pituitary cells, contrary to observations in BHK cells, preexposure with both forskolin and db-cAMP desensitised a subsequent growth hormone-releasing hormone stimulation, indicating a heterologous desensitisation. Phorbol-12-myristate 13-acetate (PMA), on the other hand, had no effect. In the baby hamster kidney cells it was demonstrated that the GHRH receptor surface expression decreased following preexposure with GHRH. This phenomenon was observed only in whole cells suggesting a rapid internalisation process. Together, these data indicate that after short-term GHRH preexposure, both in a human and rat system, the following GHRH response is desensitised. In BHK cells this desensitisation is strictly homologous. In rat pituitary cells, on the other hand, the desensitisation is a mixed homologous/ heterologous type.

Demineralized Bone Matrix-stimulated Bone Regeneration in Rats Enhanced by an Angiogenic Dipeptide Derivate

A lysyl-proline derivate (LP) known to stimulate angiogenesis and formation of granulation tissue was tested as a local additive to allogeneic demineralized bone matrix (DBM) using a rat craniotomy model. Peracetic-acid sterilized DBM (10 mg/defect) was implanted into three groups of 45 animals each with 0, 6 and 20 microg LP. Subsequent evaluation was done by descriptive histology, histomorphometry, and determination of the calcium content of the explants 7, 14, 28, 42 and 84 days post-implantation. Grafting with DBM alone resulted in defect bridging by newly formed bone with incorporated DBM residues on day 84. Addition of LP to the implants caused an enhanced capillarization on day 14 and 28 as well as an enhanced mineralization on day 14, 28, 42 and 84. Both effects were dose-dependent. These data suggest that the local application of a synthetic angiogenic factor significantly improve bone regeneration in DBM-grafted trephine defects in rats. Thereby, they reinforce the opinion that early angiogenesis is crucial for a number of subsequent events in the bone regeneration process.

Comparison of the efficacy of virus inactivation methods in allogeneic avital bone tissue transplants

Several procedures for inactivating viruses are used presently in the context of bone tissue transplants. Common methods used are gamma irradiation (25 kGy), treatment with moist heat (82.5 degrees C/15 min., lobator-sd2-system) as well as chemical sterilisation using peracetic acid-ethanol treatment (PES, 2% peracetic acid, 96% ethanol, Aqua [2:1:1], 200 mbar, agitation, 4 hours). Based on national and international guidelines, we tested the antivirucidal effectiveness of these methods in human bone transplants. Three enveloped viruses: human immunodeficiency virus type 2 (HIV-2), pseudorabies virus (PRV), bovine virus diarrhoea virus (BVDV), and three non-enveloped viruses were used: hepatitis A virus (HAV), poliovirus (PV-1), porcine/bovine parvovirus (PPV, BPV). Defatted spongiosa cuboids served as model in chemical treatment experiments, while cortical diaphyses were used in gamma irradiation experiments, and the effects of thermal treatment were tested in prepared femoral heads. The log(10) reduction was measured by cytopathogenic effects after virus titration (TCID(50)/mL). A dose of at least 33.9 kGy (bone model) at -30 +/- 5 degrees C was necessary to achieve a sufficient reduction (4 log(10) steps) of BPV, the most resistant one of all viruses investigated. Thermal treatment as well as PES treatment led to a reduction of virus titres by more than 4 log(10). Only HAV showed a reduction below 4 log(10) (2.87) with PES. After validation of the defatting step included for HAV-infected cells, a HAV-reduction of over 7 log(10) was found. All three sterilisation methods tested are recommended for bone transplant sterilisation, but only provided that additional safety measures (anamnestic informations, infectious serology, PCR in case of multiorgan donors) are taken.

Perturbations in the impact of mutational activity on Vlambda genes in systemic lupus erythematosus

To assess the impact of somatic hypermutation and selective influences on the Vlambda light chain repertoire in systemic lupus erythematosus (SLE), the frequency and pattern of mutations were analyzed in individual CD19+ B cells from a patient with previously undiagnosed SLE. The mutational frequency of nonproductive and productive rearrangements in the SLE patient was greater (3.1 x 10(-2) vs 3.4 x 10(-2), respectively) than that in normal B cells (1.2 x 10(-2) vs 2.0 x 10(-2), both P < 0.001). The frequencies of mutated rearrangements in both the nonproductive and productive repertoires were significantly higher in the patient with SLE than in normal subjects. Notably, there were no differences in the ratio of replacement to silent (R/S) mutations in the productive and nonproductive repertoires of the SLE patient, whereas the R/S ratio in the framework regions of productive rearrangements of normal subjects was reduced, consistent with active elimination of replacement mutations in this region. The pattern of mutations was abnormal in the SLE patient, with a significant increase in the frequency of G mutations in both the productive and nonproductive repertoires. As in normal subjects, however, mutations were found frequently in specific nucleotide motifs, the RGYW/WRCY sequences, accounting for 34% (nonproductive) and 46% (productive) of all mutations. These data are most consistent with the conclusion that in this SLE patient, the mutational activity was markedly greater than in normal subjects and exhibited some abnormal features. In addition, there was decreased subsequent positive or negative selection of mutations. The enhanced and abnormal mutational activity along with disturbances in selection may play a role in the emergence of autoreactivity in this patient with SLE.