Directional K+ channel insertion in a single phospholipid bilayer: Neutron reflectometry and electrophysiology in the joint exploration of a model membrane functional platform.

We investigated the insertion of small potassium (K+) channel proteins (KcvMA-1D and KcvNTS) into model membranes and the lipid-protein structural interference, combining neutron reflectometry and electrophysiology. Neutron reflectometry experiments showed how the transverse structure and mechanical properties of the bilayer were modified, upon insertion of the proteins in single model-membranes, either supported on solid substrate or floating. Parallel electrophysiology experiments were performed on the same channels reconstituted in free-standing planar lipid bilayers, of both typical composition and matched to the neutron reflectometry experiment, assessing their electrical features. Functional and structural results converge in detecting that the proteins, conical in shape, insert with a directionality, cytosolic side first. Our work addresses the powerful combination of the two experimental approaches. We show here that membrane structure spectroscopy and ion channel electrophysiology can become synergistic tools in the analysis of structural-functional properties of biomimetic complex environment.

The effect of urea and taurine as hydrophilic penetration enhancers on stratum corneum lipid models.

To optimize transdermal application of drugs, the barrier function of the skin, especially the stratum corneum (SC), needs to be reduced reversibly. For this purpose, penetration enhancers like urea or taurine are applied. Until now, it is unclear if this penetration enhancement is caused by an interaction with the SC lipid matrix or related to effects within the corneocytes. Therefore, the effects of both hydrophilic enhancers on SC models with different dimensionality, ranging from monolayers to multilayers, have been investigated in this study. Many sophisticated methods were applied to ascertain the mode of action of both substances on a molecular scale. The experiments reveal that there is no specific interaction when 10% urea or 5% taurine solutions are added to the SC model systems. No additional water uptake in the head group region and no decrease of the lipid chain packing density have been observed. Consequently, we suppose that the penetration enhancing effect of both substances might be based on the introduction of large amounts of water into the corneocytes, caused by the enormous water binding capacity of urea and a resulting osmotic pressure in case of taurine.

The internal structure of PMETAC brush/gold nanoparticle composites: a neutron and X-ray reflectivity study.

This work addresses the pH-triggered distribution and relocation of charge-stabilized gold nanoparticles (AuNPs) incorporated into strong polyelectrolyte brushes. Brush/particle composite materials were investigated under aqueous conditions and at different humidities using neutron and X-ray reflectivity, respectively. X-ray reflectivity measurements complement neutron reflectivity measurements and reveal results that could not be observed by neutron reflectivity measurements. Both methods allow scanning the particle density profile, but due to different contrasts, they are sensitive to different regions within the brush. More specifically, 3-mercaptopropionic acid (MPA)-coated AuNPs were incorporated into poly-[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) polyelectrolyte brushes at different pH values. The pH value triggers a change in the AuNP surface charge caused by the pH-sensitivity of the MPA ligands, while the charge of the PMETAC brush is not affected by pH variations. The particle number density as well as the particle distribution depend strongly on the pH value of the incubation medium: a rather non-homogeneous assembly (2D assembly) is found when the PMETAC brush is incubated in AuNP suspension at pH 4, while a more homogeneous assembly (3D assembly) is found when the PMETAC brush is incubated in AuNP suspension at pH 8. The main factor dominating the formation of 2D or 3D assembly is assigned to the particle-particle interaction and not to the particle-polymer interaction. No significant relocation of AuNPs within the brush can be found by changing the environmental conditions. The control of particle amount and distribution within the polymer brush has a strong impact on the optical properties of those composite materials, which is crucial for the fabrication of colorimetric sensors.

Pressure-induced molten globule state of human acetylcholinesterase: structural and dynamical changes monitored by neutron scattering.

We used small-angle neutron scattering (SANS) to study the effects of high hydrostatic pressure on the structure of human acetylcholinesterase (hAChE). At atmospheric pressure, our SANS results obtained on D11 at ILL (Grenoble, France) give a radius of gyration close to that calculated for a mixture of monomers, dimers and tetramers of the enzyme, suggesting a good agreement between hAChE crystal structure and its conformation in solution. Applying high pressure to the sample we found a global compression of about 11% of the enzyme up to a pressure of 900 bar and then again an extension up to 2.1 kbar indicating unfolding of the tertiary structure due to a molten globule (MG) state. On the other hand, we studied the influence of pressure up to 6 kbar on the dynamics of this enzyme, on the backscattering spectrometer IN13 at ILL. For the first time, we used elastic incoherent neutron scattering (EINS) to probe the differences between hAChE in its folded state (N), its high-pressure induced MG state and its unfolded state (U). Especially around the MG state at 1750 bar we found a significant increase in the dynamics, indicating a partial unfolding. A four-step-model is suggested to describe the changes in the protein.

The effect of hydrophilic penetration/diffusion enhancer on stratum corneum lipid models: Part II*: DMSO.

To optimize dermal and transdermal administration of drugs, the barrier function of the skin, particularly the stratum corneum (SC), needs to be reduced reversibly. For this purpose, penetration/diffusion enhancers such as DMSO can be applied. However, there is the question whether DMSO is an aggressive penetration/diffusion enhancer in pharmaceutical and cosmetical relevant concentrations? Until now, it is unclear if this penetration/diffusion enhancement is caused by an interaction with the SC lipid matrix or related to effects within the corneocytes. Therefore, the effects of the hydrophilic enhancer DMSO on SC models with different dimensionality ranging from bilayers (liposomes) via oligo-layers to multilayers have been investigated in this study. The effects of DMSO should be compared to that of other relevant hydrophilic enhancers such as urea and taurine. An innovative spectrum of methods was applied to ascertain the mode of action of DMSO in relevant concentrations on a molecular scale. The experiments reveal that there is no specific interaction of 10% and 30% DMSO solutions with the SC model systems. Hence, if DMSO is applied in pharmaceutically and cosmetically relevant concentrations, it has no influence on the SC model systems used. Neither an additional water uptake in the head group region nor a decrease of the lipid chain packing density have been observed. The leakage studies on liposomes show that 10% DMSO is causing just a very slight leakage of 8%, lower than the leakage of 19.4% caused by 10% urea (Müller et al., 2016). Consequently, the interactions of DMSO with the SC model lipids used are very low in concentrations of 10% and 30%, respectively. Since the lipid composition in native SC lipid matrix is far more complex than this model mixture, the results can not be directly transferred to the native SC lipid matrix. However, the outcome of this study, together with various findings in the literature give rise to the assumption that the enhancing effect of DMSO concerning the diffusion of relevant hydrophilic drugs and actives appears to be realized via the corneocytes.

Age-related changes and effects of regular low-intensity exercise on gait, balance, and oxidative biomarkers in the spinal cord of Wistar rats.

The present study aimed to analyze age-related changes to motor coordination, balance, spinal cord oxidative biomarkers in 3-, 6-, 18-, 24-, and 30-month-old rats. The effects of low-intensity exercise on these parameters were also analyzed in 6-, 18-, and 24-month-old rats. Body weight, blood glucose, total cholesterol, and high-density lipoprotein (HDL) cholesterol were assessed for all rats. The soleus muscle weight/body weight ratio was used to estimate skeletal muscle mass loss. Body weight increased until 24 months; only 30-month-old rats exhibited decreased blood glucose and increased total cholesterol and HDL cholesterol. The soleus muscle weight/body weight ratio increased until 18 months, followed by a small decrease in old rats. Exercise did not change any of these parameters. Stride length and step length increased from adult to middle age, but decreased at old age. Stride width increased while the sciatic functional index decreased in old rats. Performance in the balance beam test declined with age. While gait did not change, balance improved after exercise. Aging increased superoxide anion generation, hydrogen peroxide levels, total antioxidant capacity, and superoxide dismutase activity while total thiol decreased and lipid hydroperoxides did not change. Exercise did not significantly change this scenario. Thus, aging increased oxidative stress in the spinal cord, which may be associated with age-induced changes in gait and balance. Regular low-intensity exercise is a good alternative for improving age-induced changes in balance, while beneficial effects on gait and spinal cord oxidative biomarkers cannot be ruled out because of the small number of rats investigated (n=5 or 6/group).

Protein and lipid metabolism adjustments in silver catfish (Rhamdia quelen) during different periods of fasting and refeeding.

The fish may experience periods of food deprivation or starvation which produce metabolic changes. In this study, adult Rhamdia quelen males were subjected to fasting periods of 1, 7, 14, and 21 days and of refeeding 2, 4, 6, and 12 days. The results demonstrated that liver protein was depleted after 1 day of fasting, but recovered after 6 days of refeeding. After 14 days of fasting, mobilization in the lipids of the muscular tissue took place, and these reserves began to re-establish themselves after 4 days of refeeding. Plasmatic triglycerides increased after 1 day of fasting, and decreased following 2 days of refeeding. The glycerol in the plasma oscillated constantly during the different periods of fasting and refeeding. Changes in the metabolism of both protein and lipids during these periods can be considered as survival strategies used by R. quelen. The difference in the metabolic profile of the tissues, the influence of the period of fasting, and the type of reserves mobilized were all in evidence.

Thermodynamics of lipid multi-lamellar vesicles in presence of sterols at high hydrostatic pressure.

We compared the effect of cholesterol at different concentration on the phase behaviour of DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) multilamellar vesicles. We used pressure perturbation differential scanning calorimetry (PPC) that studies a system on the whole by giving access to relevant thermodynamic quantities, and elastic incoherent neutron scattering (EINS) that probes local motions of a system at the atomic level by allowing extraction of dynamical parameters. PPC revealed that the volume expansion coefficient of DMPC and DMPC/Cholesterol samples with 13 and 25 mol% cholesterol is a linear function of the heat capacity measured by differential scanning calorimetry. Neutron backscattering spectroscopy showed that the mean square displacements of H atoms do exhibit an increase with temperature and a decrease under increasing pressure. Cholesterol added at concentrations of 25 and 50 mol% led to suppression of the main phase transition. Taking advantage of these results, the present study aims (i) to show that calorimetry and EINS using the Bicout and Zaccai model equally permit to get access to thermodynamic quantities characterizing pure DMPC and DMPC/cholesterol mixtures, thus directly confirming the theoretical method, and (ii) to validate our approach as function of temperature and of pressure, as both are equally important and complementary thermodynamic variables.

Glyceroneogenesis in the hepatopancreas of the crab Neohelice granulata: Diet, starvation and season effects.

We determined the activity of glyceroneogenesis from [2-14C]-pyruvate, the phosphoenolpyruvate carboxykinase activity, [2-14C]-pyruvate oxidation and total lipid levels in the hepatopancreas of the crab Neohelice granulata fed with a carbohydrate-rich (HC) diet or a high-protein (HP) diet and then subjected to 5weeks of starvation, in summer and winter, to determine whether the seasonal adjustments of lipid metabolism to food scarcity are modulated by the composition of the diet previously given to the crabs. The results demonstrated that glyceroneogenesis is an active pathway in N. granulata hepatopancreas, and is regulated by seasonal variations, diet composition and starvation. This study showed that in summer the increase in the hepatopancreas glyceroneogenesis activity is among the strategies used by N. granulata fed an HP diet, to maintain the triglyceride/fatty acid cycle during starvation, a normal condition in the biological cycle of this crab. However, the administration of an HC diet reduced the glyceroneogenesis capacity in response to starvation in summer. In winter, the decrease in the glyceroneogenesis capacity in both fed (HP and HC diets) and starved crabs seems to be a strategy to reduce energy consumption and/or requirement. In contrast to the summer results, the incorporation of [2-14C]-pyruvate into 14CO2 was markedly higher in both diet (HC and HP) groups and in starved crabs during the winter. Four decades after the first study describing the glyceroneogenesis pathway in rat white adipose tissue, this pathway is evidenced for the first time in a crustacean.

BioRef II-Neutron reflectometry with relaxed resolution for fast, kinetic measurements at HZB.

We present an upgrade to the time-of-flight neutron reflectometer BioRef at the research reactor BER II of the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB). Through the integration of an additional chopper into the existing setup, the available wavelength resolution is significantly extended. Now two distinct operation modes can be used: a high resolution mode with Δλ/λ ranging from 1% to 5%, which allows for the investigation of thick films up to 4000 Å, and a high flux mode with Δλ/λ = 7%-11%. In the high flux mode, reflectivity curves from 0.007 Å-1 to 0.2 Å-1 with three angular settings can be recorded in 7 min. For a single angular setting and its respective window in Q-space, a time resolution of even less than 4 min is reached. The different configurations are documented by respective measurements (a) on a Ni-Ti multilayer and (b) the swelling kinetics of a solid-supported phospholipid coating upon incubation in a polyelectrolyte solution.

Immunological and chemical characterization of rat liver cytochrome c oxidase.

Rat liver cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase; EC 1.9.3.1) was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into 12 different polypeptide chains. Specific antisera against the holoenzyme and against purified subunits IV and VIII were used to characterize the enzyme complex. The antiserum against subunit IV precipitates from sodium dodecyl sulfate-dissociated mitochondria only subunit IV and from Triton X-100-dissolved mitochondria all 12 polypeptide chains, indicating their integral location within the enzyme complex. Different antisera against the holoenzyme only precipitate subunits IV, V and VIb from sodium dodecyl sulfate-dissociated mitochondria, suggesting the location of these subunits on the surface layer of the complex. Subunit VIII is thought to be located within the complex, since a specific antiserum does not precipitate the complex. The amino acid composition of all 12 protein subunits is different, thus excluding their origin from proteolytic degradation. The proteolytic degradation of subunit IV into IV during isolation of the enzyme was corroborated by the very similar amino acid composition of both proteins.

Implementing nurse-based systems to provide American Indian women with breast and cervical cancer screening.

OBJECTIVE: To describe the factors critical to implementation of a nurse-based system to increase access for American Indian women to breast and cervical cancer screening. MATERIAL AND METHODS: We report the experience of 103 nurses at 40 clinics who were trained to use the nurse-based screening system. In addition, the critical elements are discussed in the context of one particularly successful site. RESULTS: Fifteen factors were identified as critical to the implementation of a nurse-based cancer screening process once a nurse had been trained to perform clinical breast examinations and collect Papanicolaou (Pap) test specimens: knowledge of benefit, skills, organization, adequate return, perceived patient demand, perceived effectiveness, legitimacy, confidence, commitment, adequate resources, a data-driven iterative approach to program implementation, an objective measure of quality, leadership, the passage of time, and a focus on delivering the service to the patient. For example, in one site that was particularly successful, the nurses, administrators, and other key health-care professionals contributed their respective resources to implement the screening program. The program was also supported by the lay community, the state board of nursing, and the state health department breast and cervical cancer control program. During the 3-year study period, the 103 nurses performed screening tests on 2,483 women, and only 18 of the Pap test specimens were unsatisfactory. CONCLUSION: Nurse-based systems designed to collect high-quality Pap test specimens and perform detailed clinical breast examinations can be implemented if the factors that are critical to implementation are identified and addressed.

The Pine Ridge-Mayo National Aeronautics and Space Administration telemedicine project: program activities and participant reactions.

OBJECTIVE: To determine the response of participants to the Pine Ridge-Mayo National Aeronautics and Space Administration telemedicine project. DESIGN: We describe a 3-month demonstration project of medical education and clinical consultations conducted by means of satellite transmission. Postparticipation questionnaires and a postproject survey were used to assess the success of the activity. MATERIAL AND METHODS: Patients and employees at the Pine Ridge Indian Health Service Hospital in southwestern South Dakota and employees at Mayo Clinic Rochester participated in a telemedicine project, after which they completed exit surveys and a postproject questionnaire to ascertain the acceptability of this mode of health care. RESULTS: Almost all Pine Ridge and Mayo Clinic participants viewed the project as beneficial. The educational sessions received favorable evaluations, and almost two-thirds of the patients who completed evaluations thought the consultation had contributed to their medical care. More than 90% of the respondents from Pine Ridge and more than 85% of the respondents from Mayo Clinic Rochester said that they would recommend participation in this project to others. More than 90% of respondents from Pine Ridge and 80% of Mayo respondents agreed with the statement that the project should continue. CONCLUSION: These data suggest that a program of clinical consultation services, professional education, and patient education available by telemedicine might be viewed as beneficial.

A program to increase breast and cervical cancer screening for Cambodian women in a midwestern community.

OBJECTIVE: To determine local screening rates for breast and cervical cancer screening among Cambodian women older than 50 years of age who had used the health-care system, to compare these rates with those for non-Cambodian women, to identify barriers to screening among Cambodians, and to implement community screening. MATERIAL AND METHODS: From review of medical records, cancer screening rates for 1 year among Cambodians (N = 57) were compared with rates for a matched non-Cambodian sample (N = 57). Southeast Asian focus groups identified barriers to screening as a basis for intervention. The intervention included community informational programs in the Cambodian language, group screening appointments, provision of transportation, use of female physicians and interpreters, and an informal clinic setting. Cancer screening rates were compared before and after the intervention. RESULTS: Initial screening rates for Cambodians were significantly lower than for the non-Cambodians. Expressed barriers included lack of knowledge about cancer, shyness at physical examination, lack of transportation, fear of a large, technical medical center, and individual appointments. After the intervention, community screening rates were almost 5 times higher than at baseline. CONCLUSION: The intervention was successful in overcoming organizational, economic, and cultural barriers to cancer screening among older Cambodian women in this setting.

Effectiveness of mitoxantrone on the proliferation of cell cultures derived from malignant mesenchymal tumors of human origin.

The antiproliferative potency of mitoxantrone (MITOX) has predominantly been established for epithelial and hematologic neoplasias. In this study the effectiveness of MITOX was investigated in vitro for 6 sarcomatous human cell lines derived from 2 synovial sarcomas, a malignant schwannoma, a malignant histiocytoma, a leiomyosarcoma, and a chondrosarcoma. The examination was performed using a proliferation assay with monolayer cell cultures. The effect of MITOX was compared with that of adriamycin (ADR) and cisplatin (CDDP). For each drug at least 3 concentrations were tested which covered the therapeutically achievable range, i.e., for MITOX 0.2-0.002 micrograms/ml, for ADR 0.5-0.005 micrograms/ml, and for CDDP 5.0-0.05 micrograms/ml. Test incubations were performed for 3 days. Antiproliferative potency of the cytostatic drugs was assessed by counting the number of cells at the start and the end of the test period with and without drug addition. Furthermore the dose inhibiting cell growth to 50% of controls (ID50) was determined for MITOX. For comparison 4 cell lines from carcinomatous lesions were included in the study. MITOX inhibited proliferation rates of 4 sarcomatous tumor cell lines more intensively than ADR, and was less effective in 2 cell lines. However, these differences were not significant. In all mesenchymal cell lines tested the antiproliferative potency of MITOX was more pronounced than that of CDDP. In carcinomatous cell lines the MITOX-induced growth inhibition was similar to that found in response to administration of ADR and CDDP confirming the described effect on epithelial tumors. The study suggests that MITOX possesses a growth inhibitory potency for malignant soft tissue tumors in vitro. From these data it may be worthwhile to initiate clinical trials testing the treatment of sarcomatous lesions with MITOX.

The quality of Pap test specimens collected by nurses in a breast and cervical cancer screening clinic.

BACKGROUND: It is possible that nurses can help close the gap between the Healthy People 2000 clinical preventive services goals and current cancer screening rates by collecting Pap test specimens in clinical practices. The purpose of this analysis was to determine whether nurses can collect high-quality Pap tests. DESIGN: Retrospective cohort analysis of all Pap tests submitted to a commercial pathology laboratory between January 1, 1996 and July 31, 1996. Pap tests collected by the nurses at Rosebud Hospital (N = 404) were compared to the Pap tests collected by other providers at the Rosebud Hospital (N = 118) and the Pap tests collected by providers from all other sites (N = 22,696). SETTING: The Indian Health Service Hospital, Rosebud, South Dakota. SUBJECTS: Eight nurses who had been trained to collect Pap test specimens. MAIN OUTCOME MEASURES: The proportion of Pap test specimens that were wholly satisfactory and the proportion of Pap test specimens collected from nonpregnant patients that lacked endocervical cells. RESULTS: The proportion of specimens that were wholly satisfactory was 79.8% (95% CI = 75.9-83.7) for the nurses, 65.3% (95% CI = 56.7-73.9) for other Rosebud providers, and 81.7% (95% CI = 81.2-82.2) for non-Rosebud providers. The proportion of specimens that lacked endocervical cells and were from nonpregnant patients was 6.4% (95% CI = 4.0-8.8) for Rosebud nurses, 8.5% for other Rosebud providers (95% CI = 3.5-13.5), and 7.9% for non-Rosebud providers (95% CI = 7.6-8.2). CONCLUSIONS: After one week of training, nurses can collect Pap test specimens that are of the same quality as the specimens collected by physicians, nurse practitioners, and physician assistants. The widespread availability of female nurses and the high quality of their work suggest that they can contribute to the Healthy People 2000 goals by collecting Pap test specimens.

The psychological impact of modeling in a cancer survivors' fashion show.

Our objective was to assess whether cancer survivors can serve as models to promote cancer prevention and screening without suffering psychological discomfort themselves. The disease coping literature suggests that if women knew more about what cancer treatment and life after surviving cancer were like, they would be more likely to accept cancer screening tests. Because cancer survivors are living examples showing that people can survive and thrive after cancer, survivors have the potential to promote cancer screening by teaching others in their community. However, if cancer survivors are to be asked to accept this task, it is essential to demonstrate that this activity does not cause psychological suffering for them. Cancer survivors were invited (n = 31) or volunteered (n = 22) to model in a cancer survivors' fashion show. All were asked to complete a brief biographical sketch before the event and a convenience subsample was interviewed by a trained ethnographer. A brief questionnaire was mailed to the models after the event. Individuals who did not return the mailed questionnaire were contacted by telephone. Forty-two of the models completed the mailed questionnaire and 10 were contacted by telephone. The models tended to report that the experience was very positive for themselves (mean = 9.0, standard deviation [SD] = 1.3 on a scale of 0 to 10 where 0 is extremely negative and 10 is extremely positive) and for their family and friends who attended the fashion show (mean = 9.1, SD = 1.3 on the same scale). Under the proper conditions, modeling survivorship to others can be a rewarding experience for cancer survivors. While the models are easy to recruit, it remains to be demonstrated that cancer survivors are effective lay advocates for cancer prevention and screening. Medical Subject Headings (MeSH): mammography, recruitment, cancer survivors, psychological effects.

Different hormonal patterns in human menopausal gonadotropin-treated, clomiphene citrate-treated, and untreated conception cycles.

Serum concentrations of seven different hormones were analyzed during 189 singleton conception cycles. One hundred nine women were treated with human menopausal gonadotropin (hMG), 52 women received clomiphene citrate (CC), and 28 became pregnant spontaneously. Serum progesterone (P) levels in hMG-treated women started to increase on day 18 of the cycle and reached peak concentrations between days 28 and 32 of the cycle. Serum estradiol (E2) concentrations paralleled the P patterns. In hMG-treated women, there were significant correlations between serum E2 and P concentrations and the number of the mature follicles observed before ovulation (both P less than 0.01). CC-treated and spontaneous conception cycles revealed significantly lower serum levels of P, E2, testosterone, 17 alpha-hydroxyprogesterone, and prolactin, compared with hMG-treated cycles (P less than 0.05). Elevations of the gonadal steroids in hMG-treated women possibly reflect the multiple corpora lutea formed after multiple ovulations.

[Volumetric and morphological CT parameters for assessing prognosis and treatment control in hepatocellular carcinoma undergoing arterial chemoembolization]. / Volumetrische und morphologische CT-Parameter zur Prognoseabschätzung und Therapiekontrolle des hepatozellulären Karzinoms unter arterieller Chemoembolisation.

PURPOSE: To evaluate volumetric CT data as a guide for indication and assessment of prognosis for transarterial chemo-embolisation (TAE) of hepatocellular carcinomas (HCC). MATERIAL AND METHOD: 74 patients with HCC were treated with repeated TAE. 50 mg Adriblastin/m2 body surface, 50 mg cisplatin/m2 body surface and 10 ml lipiodol were combined with 2-10 ml Spherex and injected selectively (25 cases) or superselectively (49 cases); in 28 patients a single injection and in 46 patients multiple injections were used. RESULTS: CT findings before and after the procedure showed a solitary lesion in 17 patients, two lesions in 18 patients and in 39 patients there were three or more lesions. Mean expectation of life was 523 days (median = 372 days; 57% of one year survival probability). In 29 patients with > 75% lipiodol retention, mean survival was 819 days; in 17 patients with < 75% lipiodol retention it was 382 days; lower lipiodol retention of < 50% it was 231 days (< 25% 192 and < 10% 152 days). A statistically significant relationship (p < 0.0001) could be established between survival time and tumour volume, relationship of tumour to liver volume, intratumoral lipiodol retention, the type of tumour growth and the number of liver segments involved. CONCLUSION: TAE provides best survival rates after repeated injections of solitary HCC with tumour volumes < 50 ml and > 75% intra-tumoral lipiodol retention.

[Multi-sequential arterial chemoembolization of advanced hepatocellular carcinomas: computerized tomography follow-up parameters for evaluating effectiveness of therapy]. / Multisequentielle arterielle Chemoembolisation fortgeschrittener hepatozellulärer Karzinome: Computertomographische Verlaufsparameter zur Beurteilung des Ansprechens auf die Therapie.

PURPOSE: An evaluation of clinical and computed tomography parameters for the transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Retro- and prospective analysis of 123 TACE procedures in 37 patients (mean age: 63.3 years). RESULTS: Overall mean survival rate for all treated patients was 785 days with a mean value of 387 days. The 1 year survival rate was 62%. Quantitative tumor volumetry revealed a significant difference in survival rate with a mean value of 678 days for patients with a reduction of tumor volume between 0 and 50%, 976 days for a volume reduction of 51-100% and 277 days for an increase in tumor volume during therapy. Patients with a high lipiodol retention presented improved survival data (902 days) versus patients with a low lipiodol retention (513 days). Homogeneous retention of lipiodol was a positive factor on survival as compared to an inhomogenous form of retention. CONCLUSION: In patients with a positive therapy response after TACE the prognosis can be improved by repeated embolization.