Palmitic acid coating of allogeneic cancellous bone for local antibiotic treatment: A porcine impaction bone grafting model.

Introduction: The worldwide rising number of joint replacements results in increasing revision surgery including a relevant portion of septic loosening accompanied by bone deficiencies. Loading of allogeneic bone with antibiotics provides high local antibiotic concentrations and might eradicate bacteria which appear resistant to systemic antibiotic application. Hydrophobic palmitic acid was shown to be a suitable carrier for antibiotics and prevents biofilm. Methods: Cancellous bone derived from 6 to 7 months old piglets was used for a standardized in vitro impaction bone grafting model according to previous studies. The specimens were either thermodisinfected or remained native and palmitic acid with one third and two third partial weight were added and compared with control. Shear force at the interface prosthesis to cement and between cement and bone was measured. The relative micromovements were measured with 6 inductive sensors with a resolution of 0.1 µm at three different measuring heights up to a maximum movement of 150 µm between cement and bone. Taking into account the corresponding applied torque the measured values were normalized in µm/Nm. Statistical analysis was done with SPSS Statistics® Version 26.0 IBM. Results: Smallest movement was measured for thermodisinfected cancellous bone and a not significant decrease of shear force resistance with addition of palmitic acid was found since supplementing native cancellous bone reduced shear force resistance significantly depending on the weight percentage of palmitic acid. Conclusion: Supplementation of porcine cancellous bone with palmitic acid did not significantly reduce shear force resistance of thermodisinfected bone since adding palmitic acid to native bone decreased it significantly depending on the volume added. Palmitic acid seems to be a suitable coating for allogeneic cancellous bone to deliver high local antibiotic concentrations and thermodisinfected cancellous bone might be able to store larger volumes of palmitic acid than native bone without relevant influence on shear force resistance.

Transfer of Non-Dioxin-Like Polychlorinated Biphenyls (ndl-PCBs) from Feed and Soil into Hen Eggs.

Understanding the transfer of non-dioxin-like polychlorinated biphenyls (ndl-PCBs) into foods of animal origin is crucial for human health risk assessment. In two experiments, we investigated the transfer of ndl-PCBs from contaminated feed and soil into eggs and meat of laying hens. The transfer from the feed was investigated with 30 laying hens. The treated hens were divided into two groups fed a contaminated diet (12.8 µg/kg sum of indicator ndl-PCBs; 88% dry matter (DM)) for 28 and 63 days, respectively, and then experienced a depuration period of 100 days with control feed. The transfer from soil was investigated with 72 laying hens kept in three separate outdoor pens (with three levels of ndl-PCB soil contamination) for 168 days. In both experiments, eggs were collected and analyzed for ndl-PCBs. In the second experiment, animals (n = 3 at the beginning, n = 6 per group after 42, 84, and 168 days) were slaughtered to determine ndl-PCBs in meat (breast muscle tissue) fat. The transfer of ndl-PCB from both feed and soil was clearly measurable and concentrations in eggs quickly exceeded maximum levels. Clear differences between individual congeners were observed. In particular, the low-chlorinated ndl-PCBs 52 and 101 are hardly found in eggs, despite their relatively high concentration in feed and soil. PCBs 138, 153, and 180, on the other hand, were found in large proportions in eggs and meat.

Effect of synthetic bone replacement material of different size on shear stress resistance within impacted native and thermodisinfected cancellous bone: an in vitro femoral impaction bone grafting model.

Antibiotic carrier particles of variable size might influence mechanic properties within impacted thermodisinfected and native cancellous bone different. Herafill®G containing calciumsulfate and calciumcarbonate provides high local concentrations of gentamicin being important for revision surgery in infected joint replacements. Native and thermodisinfected cancellous bone derived from 6 to 7 months old piglets was used for in vitro impaction bone grafting and supplemented each with Herafill®G granules of two different sizes. Micromovement of implants related to shear force was measured in 29 specimens distributed in 6 groups. Thermodisinfected cancellous bone revealed a significant higher shear force resistance than native bone with a mean difference of 423.8 mdeg/Nm (p < 0.001) ranging within 95% confidence interval from 181.5 to 666.0 mdeg/Nm. Adding small granules to thermodisinfected bone did not reduce shear force resistance significantly since adding large granules to native bone improved it by 344.0 mdeg/Nm (p < 0.003). Shear force resistance was found higher at the distal region of the implant compared to a proximal point of measurement throughout all specimens. Less impaction impulses were necessary for thermodisinfected bone. Thermodisinfected cancellous bone might achieve a higher degree of impaction compared with native bone resulting in increased resistance against shear force since impaction was found increased distally. Supplementation of thermodisinfected bone with small granules of Herafill®G might be considered for application of local antibiotics. Large granules appeared more beneficial for supplementation of native bone. Heterogeneity of bone graft and technical aspects of the impaction procedure have to be considered regarding the reproducibility of femoral impaction bone grafting.

Influence of antibiotic pellets on pore size and shear stress resistance of impacted native and thermodisinfected cancellous bone: An in vitro femoral impaction bone grafting model.

INTRODUCTION: Morphology and mechanic properties of impacted cancellous bone are affected by carrier substances which provide high local concentrations of antibiotics. METHODS: Bone chips were taken from the femoral head of 6-7 months old piglets. One half was thermodisinfected and the other remained native. Ten specimens each were mixed with Herafill® antibiotic pellets and a control group of each 10 specimens respectively was examined. The cancellous bone was impacted according to Exeter technique and the implants were cemented. The distribution of the particles and the pores were defined with three dimensional computertomographic scan and shear force resistance was measured until failure. RESULTS: Shear force resistance was not measured significantly less for thermodisinfected (2.7 Nm) compared with native bone (3.5 Nm) and addition of antibiotic pellets reduced shear force resistance in both groups since this was significant for the native group. The average pore volume of the native bone specimens appeared significant smaller compared to the thermodisinfected group (p = 0.011) and the pore volume showed a negative correlation with shear force resistance (p = 0.044). Pore volume around the pellets was found significantly increased and it appeared smaller for native bone. The number of pellets located next to the implant showed a negative correlation with shear force resistance (p = 0.034) and the negative correlation increased for pellets below the tip of the shaft model (p = 0.024). CONCLUSION: Adding antibiotic pellets to native and thermodisinfected impacted cancellous bone increased pore volume since the area around the pellets showed increased porosity which correlated with reduced shear force resistance. Computertomographic three dimensional measurement of porosity might predict shear force resistance of impacted cancellous bone and improve impaction of bone grafting intraoperatively.

Clinical evaluation of a novel press-fit acetabular cup using "Ein-Bild-Roentgen-Analysis" (EBRA): A positive short-term prognosis.

INTRODUCTION: Demographic change and demand for high quality of life lead to increasing implantation numbers. Aim of this study was to compare the Plasmafit® cup to Allofit® and Plasmacup®. METHODS: The study included 174 patients who had received 33 Plasmacup®, 68 Allofit® and 73 Plasmafit® cup implants. These were reviewed postoperatively, after 6 months control and after 12 months. RESULTS: No significant progressive migration could be discovered in any of the cup systems. At each follow-up the cups showed nearly constant values. CONCLUSIONS: All examined acetabular cups showed excellent migration behavior within the first 12 postoperative months.

Different injury patterns after snowboard in children and adolescents.

BACKGROUND: Snowboarding is a very common sport especially among young adults. Common injuries are hand, wrist, shoulder and ankle injuries. PURPOSE: of this study was to analyze different injury pattern in children and young adults comparing with adults. METHODS: Patients who were admitted for ambulant or stationary treatment as a result of injury practicing snowboard received a questionnaire and were divided into three groups (children, young adults and adults) according to their age. Between october 2002 and may 2007 1929 injured snowboard sportsmen were included in the study. Data such as location, date and time of accident as well as information about the slope were carried out. In addition snowboard skills were classified and patients were questioned whether they wore special protectors. RESULTS: 32.5% of injured patients were female (n = 626) and 67.5% male (n = 1303) with a mean age of patients of 21.9 (7-66) years. 13% of all patients were in group I (children), 19.2% in group II (young adults) and 67.8% in group III (adults).Most common injuries with 60% of all accidents were injuries of the hand wrist especially in children beginning with snowboard sports. Injuries on the regular track were most common followed by jumps in the kicker park and rails in the fun-park. 20.6% in group I, 13.6% in group II and 12.8% group III did not wear any protectors. CONCLUSION: Children and adolescents presented different injury patterns than adults. Young participants of up to 14 years of age are endangered especially during the first days of learning this sport. Further development of protectors with regard to biomechanical characteristics is important to achieve an optimal protective effect. LEVEL OF EVIDENCE: 2b.

Instrumented gait analysis in patients with medial osteoarthritis of the knee after mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an effective treatment for patients with medial osteoarthritis of the knee joint. Instrumented gait analysis provides an objective measure to quantify and qualify postoperative changes of gait. The purpose of this study was to evaluate standardized instrumented gait analysis for functional recovery and gait as an outcome of mobile-bearing UKA in patients with medial osteoarthritis of the knee. METHODS: Twenty-one patients with isolated medial osteoarthritis of the knee joint received mobile-bearing UKA. They were examined by a gait analysis before surgery and after an average follow-up time of seven months. Gait analysis was performed on a treadmill with six infrared-cameras to identify changes of gait characteristics (e.g., velocity, stride time, stride length, knee adduction and hip abduction). RESULTS: Mean velocity (chosen by individuals) increased from 0.61 to 0.76m/s and further significant advancements, particularly in the knee adduction and the hip abduction were detected. Time and length of strides improved significantly as well as the clinical scores American Knee Society Score (AKSS), Oxford-12, Hannover Functional Ability Questionnaire for Osteoarthritis (FFbH-OA) Score and Devane Score. CONCLUSION: Mobile-bearing UKA can restore physiological axis of the leg and improve gait and function of the knee joint. The combination of instrumented gait analysis with clinical scores constitutes an eligible measuring instrument to quantify and qualify changes in patients' gait patterns.

[Influence of thermodisinfection on impaction of cancellous bone : An in vitro model of femoral impaction bone grafting]. / Einfluss der Thermodesinfektion auf die Impaktion spongiöser Knochen : Ein In-vitro-Modell für das femorale Impaction-Bone-Grafting.

BACKGROUND: The reconstruction of bony defects during endoprosthesis revision surgery using "impaction bone grafting" leads to the possibility of a longstanding osseous integration to achieve good clinical results. Native allogeneic cancellous bone is often used for the procedure. This study examines the influence of thermodisinfection on the impaction behaviour of cancellous bone of different geometries and on the cement distribution. METHODS: The cancellous bone was obtained from the femoral heads of 7­month old pigs. One half of the head was thermodisinfected while the other remained native. Bone chips with sizes of 3-5, 5-8 and 8-10 mm were produced. The impaction was performed in a cylinder model with an internal diameter of 30 mm and with standardized impaction force using an impactor with a weight of 1450 g. The best particle combination was used for the subsequent computer tomography examination of the cement distribution and the contact surface to the bone in different parts of the shaft in seven investigations. For statistic measurements two-dimensional variance analysis including repetitions of measurement and Bonferroni correction, the LSD post-hoc-zest and the Mann Whitney U Test were used. The error probability was set at α = 5%. The SPSS® for Windows software was used for the statistical analysis. RESULTS: The distribution of the cancellous and compacted bone also along the shaft revealed no significant difference between thermodisinfected and native cancellous bone at different levels (p > 0.05). Impacted native cancellous bone showed less inclusion of air, which resulted in a better distribution of density compared with thermodisinfected bone overall (p < 0.001). In the distal shaft area the cement volume was significantly larger in conjunction with the native bone. The overall area of cement penetration appeared to be significantly larger for native cancellous bone (p < 0.001). CONCLUSIONS: The impaction of thermodisinfected and native cancellous bone showed greater deformation of the processed bone without any significant difference in the maximum density reached at different levels. Cement volume and cement penetration were pronounced proximally in native and processed cancellous bone. The cement distribution was significantly more distal for the native bone. Distally, the stabilization of the shaft appears to be increasingly dependent on the density of the impacted spongiosa, while proximally, the penetration of the cement into cancellous bone seems to correlate with porosity.

[A micro-education programme for breastfeeding women: a pilot study to investigate the educations' effect on injured and painful nipples]. / Mikroschulungsprogramm für stillende Wöchnerinnen: Pilotstudie zur Auswirkung der Schulungen auf schmerzende und wunde Mamillen.

Injured and painful nipples are frequently occurring events in nursing women during the first days after giving birth. These problems often result in a premature termination of breastfeeding despite the mother's wish to nurse. Unsystematic instructions given to women regarding correct breastfeeding increase the risk that these complications will arise. The objective of the study was to investigate the effect of a systematic micro-education programme for nursing women by means of a pilot study or a quasi-experiment. The study included 100 mother and child pairs each in the experimental group and in the control group (N = 200). The pain experienced by all women during nursing was measured using the Visual Analogue Scale (VAS) and the degree of injury to the nipples after nursing was measured with a tool specially developed for this purpose, the Nipple Wound Score (NWS). Women who received instructions by means of the micro-education programme exhibited significantly less injured nipples (on the third day: experimental group 55 % and control group 77 %, p < 0.00; on the fourth day: 56 % and 80 %, p < 0.00).No differences were observed between the study groups in regard to the occurrence of pain (on the fourth day p = 0.68). The variables of birthing method, parity, age or nationality of the women had no effect on the degree of injury of the nipples or on the intensity of pain. The results of this pilot study suggest that repeated micro-education for breastfeeding women should be implemented during the first days after giving birth.

Intra-tumoral gene delivery of feIL-2, feIFN-gamma and feGM-CSF using magnetofection as a neoadjuvant treatment option for feline fibrosarcomas: a phase-I study.

Despite aggressive pre- or postoperative treatment, feline fibrosarcomas have a high relapse rate. In this study, a new treatment option based on immune stimulation by intra-tumoral delivery of three feline cytokine genes was performed. The objective of this phase-I dose-escalation study was to determine a safe dose for further evaluation in a subsequent phase-II trial. Twenty-five client-owned cats with clinical diagnosis of fibrosarcoma - primary tumours as well as recurrences - entered the study. Four increasing doses of plasmids coding for feIL-2, feIFN-gamma or feGM-CSF, respectively, were previously defined. In groups I, II, III and IV these doses were 15, 50, 150 and 450 microg per plasmid and a corresponding amount of magnetic nanoparticles. Two preoperative intra-tumoral injections of the magnetic DNA solution were followed by magnetofection. A group of four control cats received only surgical treatment. Side effects were registered and graded according to the VCOG-CTCAE scale and correlated to treatment. Statistical analyses included one-way anova, post hoc and Kruskal-Wallis tests. ELISA tests detecting plasma feIFN-gamma and plasma feGM-CSF were performed. One cat out of group IV (450 microg per plasmid) showed adverse events probably related to gene delivery. As these side effects were self-limiting and occurred only in one of eight cats in group IV, this dose was determined to be well tolerable. Altogether six cats developed local recurrences during a 1-year observation period. Four of these cats had been treated with dose IV. Regarding these observations, a subsequent phase-II trial including a representative amount of cats should be tested for the efficacy of dose IV as well as dose III.

Leukemia-targeting ligands isolated from phage-display peptide libraries.

Ligands specifically binding to leukemia cells may be used for drug targeting, resulting in more effective treatment with less side effects. Little is known about receptors specifically expressed on acute myeloid leukemia (AML) cells or ligands thereof. We selected random phage display peptide libraries on Kasumi-1 AML cells. A peptide with the sequence CPLDIDFYC was enriched. Phage displaying this peptide strongly bound to Kasumi-1 and SKNO-1 cells and binding could be inhibited by the cognate peptide. Both, Kasumi-1 and SKNO-1 cells carry the chromosomal translocation t(8;21), leading to aberrant expression of the fusion protein AML1/ETO. CPLDIDFYC also strongly and specifically bound primary AML1/ETO-positive AML blasts as well as U-937 cells with forced AML1/ETO expression, suggesting that the CPLDIDFYC receptor may be upregulated upon AML1/ETO expression. Gene expression profiling comparing a panel of CPLDIDFYC-binding and CPLDIDFYC-nonbinding cell lines identified a set of potential receptors for the CPLDIDFYC peptide. Further analysis suggested that alpha4beta1 integrin (VLA-4) is the CPLDIDFYC receptor. Finally, we showed that the CPLDIDFYC-phage is internalized upon receptor binding, suggesting that the CPLDIDFYC-receptor-ligand interaction may be exploitable for targeting drugs or gene therapy vectors to leukemia cells carrying the suitable receptor.

Primary melanoma of the female genital system: a report of 10 cases and review of the literature.

BACKGROUND: Primary melanoma of the female genital system are extremely rare (2-3%). PATIENTS AND METHODS: A retrospective review was undertaken of patients with primary melanoma of the female genital system treated from 1990-2003 at Rostock University Hospital, Germany. Different treatments (sentinel node biopsy, inguinofemoral lymphadenectomy, en bloc resection, adjuvant Interferon-alpha-therapy, adjuvant chemotherapy) are discussed. The complicated classification is reduced to a clinical path for daily use (UICC stage and invasion depth of Breslow, Clark's level and Chung's level). RESULTS: We report on 10 patients, aged 26 to 76 years, with primary melanoma of the female genital tract. Seven women developed a vulvar melanoma and one woman a malignant melanoma of the cutaneous inguinal region, while another 2 women had an unusual primary location of the malignant melanoma, the cervico-vaginal region (n=1) and the left ovary (n = 1). CONCLUSION: Initial surgical modality did not influence long-term survival, but affected disease-free survival significantly.

Vaginal metastasis of lung cancer: a case report.

BACKGROUND: Lung cancer is the second most common malignant tumor, with increasing incidence in the female population. The most frequent metastatic sites are the regional lymph nodes and surrounding areas as well as liver, adrenal gland, bones and brain. Metastases in the vagina of primary lung cancer have not been previously reported. CASE REPORT: Lung cancer was diagnosed in a 67-year-old, postmenopausal woman. Two years following partial lung resection (right apical lobe, R0-resection, CR), the patient complained of increasing problems with urination. A suspect tumor was identified with palpation and confirmed sonographically. Histological and immunohistochemical examinations of a vaginal excisional biopsy revealed metastatic adenocarcinoma, with the staining reactivity as primary lung neoplasm. Anterior exenteration was performed. CONCLUSION: Some cases of vaginal metastases from extragenital tumors have been previously reported. This is the first report of vaginal metastases from primary lung cancer. We suggest that adenocarcinoma especially tend to form metastases in the female genital tract. The present case emphasizes that, in women with unclear symptoms and findings in the small pelvis (e.g. urination problems, suspect vaginal tumor), the formation of such metastases should be taken into account.

Deletion of the tissue response against alginate-pll capsules by temporary release of co-encapsulated steroids.

Transplantation of encapsulated living cells is a promising approach for the treatment of a wide variety of diseases. Large-scale application of the technique, however, is hampered by inflammatory responses against the capsules. In the present study, we investigate whether tissue responses against alginate-PLL-alginate capsules can be modulated by co-encapsulation and temporary release of immunomodulating factors such as dexamethasone. Such an approach may be mandatory in order to increase the function and survival of encapsulated tissue since it has been shown that the tissue response can be caused by many, insurmountable factors. In an in vitro assay, we demonstrated an antiproliferative effect of dexamethasone-containing capsules on L929-mouse-fibroblasts. Subsequently, capsules prepared of purified alginate with or without solved dexamethasone were implanted in the peritoneal cavity of rats and retrieved one month later for histological evaluation. Most of the capsules without dexamethasone proved to be overgrown and adherent to the abdominal organs whereas with co-encapsulated dexamethasone the majority of the capsules were found freely floating in the peritoneal cavity without overgrowth. We conclude that co-encapsulation of dexamethasone has a profound effect on fibroblasts and macrophages adherence to immunoisolating capsules.

MTS colorimetric assay in combination with a live-dead assay for testing encapsulated L929 fibroblasts in alginate poly-L-lysine microcapsules in vitro.

Biomaterials such as applied in microcapsules may have harmful effects on encapsulated cells. Up to now, there are no adequate assays available for testing the function and viability of cells in capsules. Therefore, we investigated whether the combination of MTS proliferation assay and live-dead viability assay is suitable for testing microencapsulated L929 fibroblasts in long-time culture. Proliferation of L929 cells was shown by a significant increase of formazan absorbance within the first 3 weeks (Day 0: 0.132 +/- 0.047; Day 7: 0.404 +/- 0.101; Day 14: 0.728 +/- 0.239; Day 21: 0.877 +/- 0.224) followed by stagnation and decrease thereafter. This was confirmed by an increasing proportion of dead cells measured by the live-dead assay. Thus, proliferation of encapsulated L929 can be reliably investigated by the MTS assay. In combination with life-dead assays, the proliferation can be correlated to the survival rate of the encapsulated cells.

Transgenic potato (Solanum tuberosum) tubers synthesize the full spectrum of inulin molecules naturally occurring in globe artichoke (Cynara scolymus) roots.

The ability to synthesize high molecular weight inulin was transferred to potato plants via constitutive expression of the 1-SST (sucrose:sucrose 1-fructosyltransferase) and the 1-FFT (fructan: fructan 1-fructosyltransferase) genes of globe artichoke (Cynara scolymus). The fructan pattern of tubers from transgenic potato plants represents the full spectrum of inulin molecules present in artichoke roots as shown by high-performance anion exchange chromatography, as well as size exclusion chromatography. These results demonstrate in planta that the enzymes sucrose:sucrose 1-fructosyltransferase and fructan:fructan 1-fructosyltransferase are sufficient to synthesize inulin molecules of all chain lengths naturally occurring in a given plant species. Inulin made up 5% of the dry weight of transgenic tubers, and a low level of fructan production also was observed in fully expanded leaves. Although inulin accumulation did not influence the sucrose concentration in leaves or tubers, a reduction in starch content occurred in transgenic tubers, indicating that inulin synthesis did not increase the storage capacity of the tubers.

Signal formation and decay in CdTe x-ray detectors under intense irradiation.

The response of Cd(Zn)Te Schottky and resistive detectors to intense x-rays is investigated in a commercial computed tomography (CT) system to assess their potential for medical diagnostics. To describe their signal height, responsivity, signal-to-noise ratio (SNR), and detective quantum efficiency the devices are modeled as solid-state ionization chambers with spatially varying electric field and charge collection efficiency. The thicknesses and pixel areas of the discrete detector elements are 0.5-2 mm and a few mm2, respectively. The incident spectrum extends from 26 to 120 keV and comprises 10(10) quanta/s cm2. It photogenerates a carrier concentration in the semiconductor that is two to three orders of magnitude above the intrinsic concentration, but remains to a similar extent below the charge densities on the device electrodes. Stable linear operation is achieved with the Schottky-type devices under high bias. Their behavior can be modeled well if negatively charged near-midgap bulk defects with a concentration of 10(11)-10(13) cm-3 are assumed. The bulk defects explain the amount and time constant (about 100 ms) of the detrapping current measured after x-ray pulses (afterglow). To avoid screening by the trapped space charge the bias voltage should exceed 100(V) x [detector thickness/mm]2. Dark currents are of the order of the generation-recombination current, i.e., 300 pA/mm3 detector volume. With proper device design the signal height approaches the theoretical maximum of 0.2 A/W. This high responsivity, however, is not exploited in CT since the SNR is determined here by the incident quantum noise. As a consequence of the detrapping current, the response speed does not meet CT requirements. A medium-term effort for crystal growth appears necessary to achieve the required reduction of the trap density by an order of magnitude. Scintillation based detectors are, therefore, still preferred in fast operating medical diagnostic systems.

An accelerator for neural networks with pulse-coded model neurons.

The labeling of features by synchronization of spikes seems to be a very efficient encoding scheme for a visual system. Simulation of a vision system with millions of pulse-coded model neurons, however, is almost impossible on the base of available processors including parallel processors and neurocomputers. A "one-to-one" silicon implementation of pulse-coded model neurons suffers from communication problems and low flexibility. On the other hand, acceleration of the simulation algorithm of pulse-coded leaky integrator neurons has proved to be straightforward, flexible, and very efficient. Thus we decided to develop an accelerator for a special version of the French and Stein neurons with modulatory inputs which are advantageous for simulation of synchronization mechanisms. Moreover, our accelerator also provides a Hebbian-like learning rule and supports adaptivity. Up to 128 K neurons with a total number of 16 M freely allocatable synapses are simulated within one system. The size of networks, however, is not at all limited by these numbers as the system may be arbitrarily expanded. Simulation speed obviously depends on the number of interconnections and on the average activity within the network. In the case of locally interconnected networks for simulation of vision mechanisms there is only a very low percentage of simultaneously active neurons: stimuli are not simultaneously presented in all orientations and at all positions of the visual field. In these cases our accelerator provides close to real-time behavior if one second of a biological neuron is simulated by 1000 time slots.

A plant transformation vector with a minimal T-DNA II. Irregular integration patterns of the T-DNA in the plant genome.

A minimal T-DNA binary vector was used for Agrobacterium-mediated transfer of a chimeric T4 lysozyme gene located next to the left border, and transgenic potato plants which expressed T4 lysozyme protein were identified and further analysed. Frequent rearrangements of T4 lysozyme transgenes were detected. A vector derivative containing two matrix associated regions (MARs) flanking its multiple cloning site was constructed. In transgenic potato plants, reduced variability in gene expression due to position effects was detected. When either the donor vector contained MAR sequences, or when vector pPCV701 which contains a pBR322 fragment next to the left border were used, only relatively few rearrangements were observed. However, when the T4 lysozyme gene was driven by a CaMV 35S promoter modified by multiplied enhancer region carrying either 2 or 4 elements, frequent rearrangements were again obtained.

Activation of transcription factor AP-2 mediates UVA radiation- and singlet oxygen-induced expression of the human intercellular adhesion molecule 1 gene.

UVA radiation is the major component of the UV solar spectrum that reaches the earth, and the therapeutic application of UVA radiation is increasing in medicine. Analysis of the cellular effects of UVA radiation has revealed that exposure of human cells to UVA radiation at physiological doses leads to increased gene expression and that this UVA response is primarily mediated through the generation of singlet oxygen. In this study, the mechanisms by which UVA radiation induces transcriptional activation of the human intercellular adhesion molecule 1 (ICAM-1) were examined. UVA radiation was capable of inducing activation of the human ICAM-1 promoter and increasing ICAM-1 mRNA and protein expression. These UVA radiation effects were inhibited by singlet oxygen quenchers, augmented by enhancement of singlet oxygen life-time, and mimicked in unirradiated cells by a singlet oxygen-generating system. UVA radiation as well as singlet oxygen-induced ICAM-1 promoter activation required activation of the transcription factor AP-2. Accordingly, both stimuli activated AP-2, and deletion of the putative AP-2-binding site abrogated ICAM-1 promoter activation in this system. This study identified the AP-2 site as the UVA radiation- and singlet oxygen-responsive element of the human ICAM-1 gene. The capacity of UVA radiation and/or singlet oxygen to induce human gene expression through activation of AP-2 indicates a previously unrecognized role of this transcription factor in the mammalian stress response.