Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women

OBJECTIVE

The aim of this study was to examine the relationship of diet with serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in women.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

The population are 2109 women who were control subjects in a case-control study of breast cancer nested in the European Prospective Investigation into Cancer and Nutrition. Control subjects were randomly chosen among risk sets consisting of female cohort members alive and free of cancer (except non-melanoma skin cancer) at the time of diagnosis of the index case. Matching criteria were age at enrolment, follow-up time, time of the day of blood collection and study centre. Diet was measured through validated questionnaires. Serum hormone concentrations were measured by enzyme-linked immunosorbent assays. The relationship between serum IGF-I, IGFBP-3, and intake of nutrients and foods was explored by linear regression in models adjusted for energy intake, age, body mass index, smoking, physical activity, centre and laboratory batch.

RESULTS

Serum IGF-I levels were positively related to protein intake (P(trend)<0.001), but not related to energy, fat or carbohydrate intake. Positive relationships were observed with the intake of milk (P(trend)=0.007), calcium (P(trend)<0.001), magnesium (P(trend)=0.003), phosphorus (P(trend)<0.001), potassium (P(trend)=0.002), vitamin B6 (P(trend)=0.03), vitamin B2 (P(trend)=0.001) and inverse relationships with vegetables (P(trend)=0.02) and beta-carotene (P(trend)=0.02). IGFBP-3 was not related with most of the nutrients and foods in this study.

CONCLUSIONS

In this population, circulating IGF-I is modestly related with the intake of protein and minerals, and with milk and cheese, while IGFBP-3 does not appear to be related with diet.

Biophysical characterisation of electrofused giant HEK293-cells as a novel electrophysiological expression system

Giant HEK293 cells of 30-65 microm in diameter were produced by three-dimensional multi-cell electrofusion in 75 mOsm sorbitol media. These strong hypotonic conditions facilitated fusion because of the spherical shape and smooth membrane surface of the swollen cells. A regulatory volume decrease (RVD), as observed at higher osmolalities, did not occur at 75 mOsm. In contrast to field-treated, but unfused cells, the increase in volume induced by hypotonic shock was only partly reversible in the case of fused giant cells after their transfer into isotonic medium. The large size of the electrofused cells allowed the study of their electrophysiological properties by application of both whole-cell and giant excised patch-clamp techniques. Recordings on giant cells yielded a value of 1.1+/-0.1 microF/cm2 for the area-specific membrane capacitance. This value was consistent with that of the parental cells. The area-specific conductivity of giant cells (diameter > 50 microm) was found to be between 12.8 and 16.1 microS/cm2, which is in the range of that of the parental cells. Measurements with patch-pipettes containing fluorescein showed uniform dye uptake in the whole-cell configuration, but not in the cell-attached configuration. The diffusion-controlled uniform uptake of the dye into the cell interior excludes internal compartmentalisation. The finding of a homogeneous fusion was also supported by expression of the yellow fluorescent protein YFP (as part of the fusion-protein ChR2-YFP) in giant cells since no plasma-membrane bound YFP-mediated fluorescence was detected in the interior of the electrofused cells. Functional expression and the electrophysiological characterisation of the light-activated cation channel Channelrhodopsin 2 (ChR2) yielded similar results as for parental cells. Most importantly, the giant cells exhibited a comparable expression density of the channel protein in the plasma membrane as observed in parental cells. This demonstrates that electrofused cells can be used as a heterologous expression system.

Plasma and dietary carotenoid, retinol and tocopherol levels and the risk of gastric adenocarcinomas in the European prospective investigation into cancer and nutrition

Despite declining incidence rates, gastric cancer (GC) is a major cause of death worldwide. Its aetiology may involve dietary antioxidant micronutrients such as carotenoids and tocopherols. The objective of this study was to determine the association of plasma levels of seven common carotenoids, their total plasma concentration, retinol and α- and γ-tocopherol, with the risk of gastric adenocarcinoma in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), a large cohort involving 10 countries. A secondary objective was to determine the association of total sum of carotenoids, retinol and α-tocopherol on GCs by anatomical subsite (cardia/noncardia) and histological subtype (diffuse/intestinal). Analytes were measured by high-performance liquid chromatography in prediagnostic plasma from 244 GC cases and 645 controls matched by age, gender, study centre and date of blood donation. Conditional logistic regression models adjusted by body mass index, total energy intake, smoking and Helicobacter pylori infection status were used to estimate relative cancer risks. After an average 3.2 years of follow-up, a negative association with GC risk was observed in the highest vs the lowest quartiles of plasma β-cryptoxanthin (odds ratio (OR)=0.53, 95% confidence intervals (CI)=0.30–0.94, P_trend=0.006), zeaxanthin (OR=0.39, 95% CI=0.22–0.69, P_trend=0.005), retinol (OR=0.55, 95% CI=0.33–0.93, P_trend=0.005) and lipid-unadjusted α-tocopherol (OR=0.59, 95% CI=0.37–0.94, P_trend=0.022). For all analytes, no heterogeneity of risk estimates or significant associations were observed by anatomical subsite. In the diffuse histological subtype, an inverse association was observed with the highest vs lowest quartile of lipid-unadjusted α-tocopherol (OR=0.26, 95% CI=0.11–0.65, P_trend=0.003). These results show that higher plasma concentrations of some carotenoids, retinol and α-tocopherol are associated with reduced risk of GC.

IGF-I, IGFBP-3 and breast cancer risk in women: The European Prospective Investigation into Cancer and Nutrition (EPIC)

Blood concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) have recently been associated with breast cancer risk, notably in women who developed breast cancer at a young age. Prospective studies published so far, however, were relatively small and odds ratio (OR) estimates imprecise. We present the results of a large prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition on total IGF-I, IGFBP-3 and breast cancer risk including 1081 incident cases of invasive breast cancer and 2098 matched control subjects. Increasing IGF-I and IGFBP-3 concentrations were associated with a significant increase in breast cancer risk in women who developed breast cancer after 50 years of age (highest vs lowest quintile OR 1.38 (95% confidence interval (CI) 1.02-1.86), P = 0.01, and 1.44 (95% CI 1.04-1.98), P = 0.01, respectively), but no relationship was observed in younger women (OR = 1.03 (95% CI 0.60-1.77), P = 0.81 for IGF-I, and OR = 0.92 (95% CI 0.50-1.70), P = 0.69 for IGFBP-3). There was, however, significant heterogeneity in the relationship of breast cancer with serum IGF-I and IGFBP-3 levels depending on the time interval between blood donation and tumor diagnosis. A reduction in breast cancer risk with increasing IGF-I concentrations was observed in cases with a diagnosis of cancer less than 2 years after blood donation, (OR = 0.76 (95% CI 0.57-1.03)), while an increase in risk was observed for women with a later diagnosis (above or equal to two years after blood collection, OR = 1.51 (95% CI 1.19-1.91)). A similar pattern was observed for IGFBP-3. This study confirms previous findings for an association of serum IGF-I and IGFBP-3 concentrations with breast cancer risk, particularly for women with a later diagnosis of cancer, but it does not support the hypothesis of an involvement of IGF-I in younger women.

Body mass index, waist circumference and waist–hip ratio and serum levels of IGF-I and IGFBP-3 in European women

OBJECTIVE

To examine the relationship between body mass index (BMI) and waist-hip ratio (WHR) with serum levels of insulin-like growth factor-I (IGF-I), and its binding protein (IGFBP)-3.

DESIGN

Cross-sectional study on 2139 women participating in a case-control study on breast cancer and endogenous hormones. Data on lifestyle and reproductive factors were collected by means of questionnaires. Body height, weight, waist and hip circumferences were measured. Serum levels of IGF-I and insulin-like binding protein (IGFBP)-3 were measured by enzyme-linked immunosorbent assays. Adjusted mean levels of IGF-I and IGFBP-3 across quintiles of BMI, waist circumference, and WHR were calculated by linear regression. Results were adjusted for potential confounders associated with IGF-I and IGFBP-3.

RESULTS

Adjusted mean serum IGF-I values were lower in women with BMI<22.5 kg/m(2) or BMI>29.2 kg/m(2) compared to women with BMI within this range (P(heterogeneity)<0.0001, P(trend)=0.35). Insulin-like growth factor-I was not related to WHR after adjustment for BMI. IGF-binding protein-3 was linearly positively related to waist and WHR after mutual adjustment. The molar ratio IGF-I/IGFBP-3 had a non-linear relation with BMI and a linear inverse relationship with WHR (P (trend)=0.005).

CONCLUSIONS

Our data confirm the nonlinear relationship of circulating IGF-I to total adiposity in women. Serum IGFBP-3 was positively related to central adiposity. These suggest that bioavailable IGF-I levels could be lower in obese compared to non-obese women and inversely related to central adiposity.

Plasma carotenoids as biomarkers of intake of fruits and vegetables: ecological-level correlations in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

The aim of this study was to assess the ability of a single 24-h dietary recall (24HDR) and food questionnaires (FQ) to predict plasma carotenoid levels at the ecological level by assessing the relationship between mean plasma carotenoid levels and mean intake of fruit and vegetables measured by 24HDR and FQ across 16 European regions.

DESIGN

A random subsample of 3089 subjects was included, stratified by age and gender. They provided blood samples and dietary information between 1992 and 2000 as part of the European Prospective Investigation into Cancer and Nutrition.

RESULTS

Using Spearman's correlation coefficients, the correlations between mean regional 24HDR fruit and vegetable variables and corresponding mean plasma carotenoid levels were generally higher than the correlations using FQ means. The highest correlation was between the 24HDR citrus fruit variable and beta-cryptoxanthin (r = 0.90). For 24HDR, total fruits and vegetables were highly correlated with lutein, zeaxanthin, and beta-cryptoxanthin (r = 0.83-0.87), while vegetables were more closely related with lutein (r = 0.69) and zeaxanthin (r = 0.68), and fruits correlated with zeaxanthin (r = 0.87) and beta-cryptoxanthin (r = 0.84). Root vegetables (r = 0.81) and total carrots (r = 0.71) were well correlated with alpha-carotene. In the multivariate models adjusting for age, body mass index, and season, and using observations of means stratified by sex and region, the association was generally higher for 24HDR compared to FQ.

CONCLUSION

Mean regional intakes of fruits and vegetables in several European countries were closely correlated with corresponding mean plasma levels of individual carotenoids. Fruits and vegetables measured by 24HDR were generally better able to predict plasma carotenoids at the ecological level.

Channelrhodopsins: directly light-gated cation channels

Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial type chromophores, i.e. all-trans-retinal in the ground state. The green alga Chlamydomonas reinhardtii was recently completely sequenced and the EST (expressed sequence tag) database was made public. We and others detected overlapping partial cDNA sequences that encode two proteins which we termed channelopsins (Chops). The N-terminal half of chop1 (approximately 300 of 712 amino acids) comprises hypothetical seven-transmembrane segments with sequence similarity to the proton pump bacteriorhodopsin and the chloride pump halorhodopsin. Even though the overall sequence homology is low, several amino acids are conserved that define the retinal-binding site and the H+-transporting network in BR (bacteriorhodopsin). Expression of Chop1, or only the hydrophobic core, in Xenopus laevis oocytes, enriched with retinal, produced a light-gated conductance (maximum at approx. 500 nm), which shows characteristics of a channel [ChR1 (channelrhodopsin-1)] that is selectively permeable for protons. Also ChR2 (737 amino acids) is an ion channel that is switched directly by light and also here the hydrophobic N-terminal half of the protein is sufficient to enable light-sensitive channel activity. The action spectrum is blue-shifted (maximum at approx. 460 nm) with respect to ChR1. In addition to protons, ChR2 is permeable to univalent and bivalent cations. We suggest that ChRs are involved in phototaxis of green algae. We show that heterologous expression of ChR2 is useful to manipulate intracellular pCa or membrane potential of animal cells, simply by illumination.

Postmenopausal serum androgens, oestrogens and breast cancer risk: the European prospective investigation into cancer and nutrition

Considerable experimental and epidemiological evidence suggests that elevated endogenous sex steroids - notably androgens and oestrogens - promote breast tumour development. In spite of this evidence, postmenopausal androgen replacement therapy with dehydroepiandrosterone (DHEA) or testosterone has been advocated for the prevention of osteoporosis and improved sexual well-being. We have conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. Levels of DHEA sulphate (DHEAS), (Delta4-androstenedione), testosterone, oestrone, oestradiol and sex-hormone binding globulin (SHBG) were measured in prediagnostic serum samples of 677 postmenopausal women who subsequently developed breast cancer and 1309 matched control subjects. Levels of free testosterone and free oestradiol were calculated from absolute concentrations of testosterone, oestradiol and SHBG. Logistic regression models were used to estimate relative risks of breast cancer by quintiles of hormone concentrations. For all sex steroids -the androgens as well as the oestrogens - elevated serum levels were positively associated with breast cancer risk, while SHBG levels were inversely related to risk. For the androgens, relative risk estimates (95% confidence intervals) between the top and bottom quintiles of the exposure distribution were: DHEAS 1.69 (1.23-2.33), androstenedione 1.94 (1.40-2.69), testosterone 1.85 (1.33-2.57) and free testosterone 2.50 (1.76-3.55). For the oestrogens, relative risk estimates were: oestrone 2.07 (1.42-3.02), oestradiol 2.28 (1.61-3.23) and free oestradiol (odds ratios 2.13 (1.52-2.98)). Adjustments for body mass index or other potential confounding factors did not substantially alter any of these relative risk estimates. Our results have shown that, among postmenopausal women, not only elevated serum oestrogens but also serum androgens are associated with increased breast cancer risk. Since DHEAS and androstenedione are largely of adrenal origin in postmenopausal women, our results indicated that elevated adrenal androgen synthesis is a risk factor for breast cancer. The results from this study caution against the use of DHEA(S), or other androgens, for postmenopausal androgen replacement therapy.

Allergic sensitisation and allergic rhinitis are associated with n-3 polyunsaturated fatty acids in the diet and in red blood cell membranes

OBJECTIVE

Due to inconsistent results based on dietary intake data, unsaturated fatty acids in red blood cell (RBC) membranes and diet were used to investigate their association with allergic sensitisation and allergic rhinitis.

DESIGN

Cross-sectional, population-based study.

SETTING

Bavarian Nutrition Survey II (2002-03), Germany.

SUBJECTS

A total of 568 adult participants, 325 women and 243 men.

METHODS

By means of logistic regression models, the relation of fatty acids to (i) allergic sensitisation as defined by means of specific serum immunoglobulin E analysis (CAPSX1 class > or = 2), and (ii) self-reported allergic rhinitis was examined.

RESULTS

A high cell membrane level of eicosapentaenoic acid (EPA, 20:5 n-3) was inversely associated with allergic sensitisation, the adjusted odds ratio (OR) and 95% confidence interval (95% CI) were 0.52 (0.30-0.90) for the highest (vs lowest) quartile. A similar effect was observed for allergic rhinitis with an OR (95% CI) of 0.50 (0.24-1.03; P = 0.027 for trend). A higher dietary intake of alpha-linolenic acid (ALA, 18:3 n-3) was associated with a decreased risk of allergic sensitisation and allergic rhinitis with ORs (95% CIs) of 0.51 (0.28-0.93) and 0.43 (0.20-0.93), respectively, in the highest quartiles. No other dietary or cell membrane unsaturated fatty acid was significantly associated with the outcome variables, nor was the n-6/n-3 ratio. The strongest effects were observed among subjects under the age of 40 y.

CONCLUSIONS

In this cross-sectional study among adults, a high content of n-3 fatty acids in RBC membranes (EPA) or in the diet (ALA) is associated with a decreased risk of allergic sensitisation and allergic rhinitis.

Plasma carotenoids as biomarkers of intake of fruits and vegetables: individual-level correlations in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

The aim in this study was to assess the association between individual plasma carotenoid levels (alpha-carotene, beta-carotene, lycopene, beta-cryptoxanthin, lutein, zeaxanthin) and fruit and vegetable intakes recorded by a calibrated food questionnaire (FQ) and 24-h dietary recall records (24HDR) in nine different European countries with diverse populations and widely varying intakes of plant foods.

DESIGN

A stratified random subsample of 3089 men and women from nine countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC), who had provided blood samples and dietary and other lifestyle information between 1992 and 2000, were included.

RESULTS

beta-Cryptoxanthin was most strongly correlated with total fruits (FQ r = 0.52, 24HDR r = 0.39), lycopene with tomato and tomato products (FQ r = 0.38, 24HDR r = 0.25), and alpha-carotene with intake of root vegetables (r = 0.39) and of total carrots (r = 0.38) for FQ only. Based on diet measured by FQ and adjusting for possible confounding by body mass index (BMI), age, gender, smoking status, alcohol intake, and energy intake, the strongest predictors of individual plasma carotenoid levels were fruits (R(partial)(2) = 17.2%) for beta-cryptoxanthin, total carrots ((partial)(2) = 13.4%) and root vegetables (R(partial)(2) = 13.3%) for alpha-carotene, and tomato products (R(partial)(2) = 13.8%) for lycopene. For 24HDR, the highest R(partial)(2) was for fruits in relation to beta-cryptoxanthin (7.9%).

CONCLUSIONS

Intakes of specific fruits and vegetables as measured by food questionnaires are good predictors of certain individual plasma carotenoid levels in our multicentre European study. At individual subject levels, FQ measurements of fruits, root vegetables and carrots, and tomato products are, respectively, good predictors of beta-cryptoxanthin, alpha-carotene, and lycopene in plasma.

The impact of comorbidity on the survival of postmenopausal women with breast cancer

PURPOSE

The aim was to assess the impact of comorbidity on survival of postmenopausal women with breast cancer diagnosis in the period 1995-1997.

METHODS

The level of comorbidity was described by the methods suggested by Satariano and Charlson. Cox's proportional hazard models were used to explore the impact of comorbidity on all-cause mortality.

RESULTS

After a median follow-up time of 52 months, an increasing level of comorbidity was associated with a higher all-cause mortality. Compared to patients with-out comorbid conditions, the hazard ration of death (HR) was 1.2 (95% CI: 0.8-1.7) for Satariano index 1 and HR 2.3 (95% CI: 1.5-3.5) for Satariano index >or=2, and HR 1.6 and 2.1 for the Charlson comorbidity index, respectively. Independent of comorbidity, the treatment pattern had a strong impact on survival. The level of comorbidity has an influence on the 3-year survival of postmenopausal women with breast cancer.

CONCLUSIONS

Long-term follow-up is required to appraise these findings in relation to treatment strategies.

Food and Nutrient Intake, Anthropometric Measurements and Smoking according to Alcohol Consumption in the EPIC Heidelberg Study

AIMS

The study was carried out to determine associations of reported alcohol intake with dietary habits, body mass index, waist-to-hip ratio (WHR) and smoking.

SUBJECTS AND METHODS

24,894 subjects who participated in the baseline examination of the German part of the European Prospective Investigation into Cancer and Nutrition (EPIC) in Heidelberg and were between 35 and 65 years of age at baseline were included in the present cross-sectional analysis (11,617 men, 13,277 women). Diet and alcohol consumption were assessed with a semiquantitative food frequency questionnaire. Analysis of covariance with age as a covariate was used to analyse the association between alcohol intake and dietary consumption patterns, BMI, WHR and smoking.

RESULTS

Alcohol did not replace other food items, but was an addition to the diet. Among alcohol consumers, fat and protein intake as a percentage of energy was slightly higher and carbohydrate intake was slightly lower than among abstainers. Alcohol consumers had a lower intake of fruits, dairy products, cereal products, and added vegetable fat and a higher intake of animal products such as meat, fish, eggs and added animal fat than abstainers. The prevalence of current smoking showed a U-shaped relation to alcohol intake in men and women. In men, a U-shaped association was also seen between the prevalence of former smoking and alcohol intake, while the prevalence of former smoking increased linearly with alcohol intake in women.

CONCLUSION

The results show that alcohol consumption is associated with dietary consumption patterns and smoking. Therefore, it will be important to consider dietary patterns and other lifestyle parameters when investigating the health effects of alcohol intake in the future.

Dietary intake of fatty acids, antioxidants and selected food groups and asthma in adults

OBJECTIVE

Within a prospective study, we explored the associations between dietary intake of fatty acids, antioxidants and relevant food sources of these nutrients on the clinical manifestation of asthma in adulthood.

METHOD

A total of 105 newly physician-diagnosed cases of asthma from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort were identified during follow-up and matched with 420 controls. Baseline dietary intake was obtained by means of validated food frequency questionnaires. The association of dietary intake variables and asthma risk was explored by unconditional logistic regression models.

RESULTS

A high intake of oleic acid (C18:1 n-9) was positively associated with asthma (P-value for trend 0.035), while no significant associations were found for the other dietary fatty acids. Most prominently, a high margarine intake increased the risk of onset of asthma in adulthood (adjusted odds ratio (OR) 3rd tertile: 1.73 (95% confidence interval (95% CI): 1.05-2.87), P for trend=0.050), the effect being stronger in men (2nd tertile: OR=1.66, 3rd tertile: OR=2.51) than in women (2nd tertile: OR=0.91; 3rd tertile: OR=1.47). The dietary intake of antioxidants and their main food sources had no effect on asthma risk.

CONCLUSIONS

In summary, the present results provide evidence that even in adulthood a high margarine intake increases the risk of clinical onset of asthma. Whether oleic acid may serve as a proxy for margarine-derived trans-fatty acids (C18:1 t9) remains to be clarified.

CFTR fails to inhibit the epithelial sodium channel ENaC expressed in Xenopus laevis oocytes

The cystic fibrosis transmembrane conductance regulator (CFTR) plays a crucial role in regulating fluid secretion by the airways, intestines, sweat glands and other epithelial tissues. It is well established that the CFTR is a cAMP-activated, nucleotide-dependent anion channel, but additional functions are often attributed to it, including regulation of the epithelial sodium channel (ENaC). The absence of CFTR-dependent ENaC inhibition and the resulting sodium hyperabsorption were postulated to be a major electrolyte transport abnormality in cystic fibrosis (CF)-affected epithelia. Several ex vivo studies, including those that used the Xenopus oocyte expression system, have reported ENaC inhibition by activated CFTR, but contradictory results have also been obtained. Because CFTR-ENaC interactions have important implications in the pathogenesis of CF, the present investigation was undertaken by our three independent laboratories to resolve whether CFTR regulates ENaC in oocytes and to clarify potential sources of previously reported dissimilar observations. Using different experimental protocols and a wide range of channel expression levels, we found no evidence that activated CFTR regulates ENaC when oocyte membrane potential was carefully clamped. We determined that an apparent CFTR-dependent ENaC inhibition could be observed when resistance in series with the oocyte membrane was not low enough or the feedback voltage gain was not high enough. We suggest that the inhibitory effect of CFTR on ENaC reported in some earlier oocyte studies could be attributed to problems arising from high levels of channel expression and suboptimal recording conditions, that is, large series resistance and/or insufficient feedback voltage gain.

[The use of the Epidemiology Cancer registry Baden-Württemberg in the follow-up of the EPIC cohort]

The European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective multicentre study that has been implemented to further the understanding of the association between diet and chronic diseases with emphasis on cancer. In Heidelberg from June 1994 until October 1998 about 25,500 subjects aged 35 to 65 years in women and 40 to 65 years in men were recruited. Apart from extensive questions about food intake, the participants were also asked to provide detailed information about their smoking habits, physical activity, subjective well-being, medical history and use of medications. As well as completing the questionnaire and a personal interview, the participants also gave blood samples and anthropometiric measures and the blood pressure were taken in standardized manner. The analyses of the EPIC study will depend on achieving a comprehensive record of all new cancer cases, and all deaths, together with the corresponding cause of death, within the study population. To date all self-reported incident cancer cases are verified by comparing them with pathology reports and hospital records. They are then coded according to the coding list for the International Classification of Diseases (ICD-O2) issued by the World Health Organisation (WHO). Since at begin of the investigation in the study region no cancer registration existed, the participants are followed -up by interval questioning ('active follow-up'). In order to integrate increasingly the data of the Cancer registry Baden-Württemberg (EKR-BW) attempts were made to explore record linkage systems. For this purpose, in the years 2000, 2002, 2003 record linkages between EPIC-Heidelberg and EKR-BW were performed. Procedures were evaluated for performing an anonymous linkage of the EPIC data with the data of the EKR-BW. After a pilot project on the feasibility of the linkage the program was evaluated on the EPIC data, record linkages are performed regularly. Different coding systems were applied. Simultaneously, the EPIC data about on cancer cases among the Heidelberg study participants are passed on to the Cancer Registry, thus contributing to improve completeness of the registry. So far the active follow-up can not be replaced by passive follow-up through record linkage with the cancer registry, but in the long-term it may be possible. Since the technical requirements are complied with, attempts should be made to improve the completeness of the epidemiological cancer registry Baden- Württemberg.

Use of complementary and alternative medicine by patients with breast cancer: observations from a health-care survey

GOALS OF THE WORK

The aim of this study was to assess the period prevalence and identify predictors of the use of complementary and alternative medicine (CAM) among women with breast cancer.

PATIENTS AND METHODS

In a cross-sectional study, 263 women participating in a quality of life survey reported on CAM use. Differences between CAM users and nonusers were evaluated using logistic regression.

RESULTS

About 3 years after diagnosis the period prevalence of CAM use among women with breast cancer was 36%. Younger women reported usage of CAM more often than older women. Associations between remote disease, pain and psychosocial variables were found. Involvement in self-help groups and active participation in leisure activities were associated with CAM use; this may indicate differences in the patients' ability to cope with the disease. Most patients were informed of CAM by a physician.

CONCLUSIONS

Involvement in self-help groups and leisure activities were associated with CAM use, indicating differences in the patients' ability to cope. Further research is necessary to evaluate the safety of CAM and to determine the value of CAM in health care.

The influence of the dietary intake of fatty acids and antioxidants on hay fever in adults

BACKGROUND

The objective of the investigation was to explore in a prospective study the associations between dietary intake of fatty acids, antioxidants and hay fever manifestation in adulthood.

METHODS

Three hundred and thirty-four hay fever cases with adult onset of clinical symptoms from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort were identified during follow-up and matched with 1336 controls. Dietary intake data were obtained by means of validated food frequency questionnaires. The influence of dietary fatty acid and vitamin intake on hay fever risk was estimated by means of unconditional logistic regression.

RESULTS

High intake of oleic acid was positively associated with hay fever [odds ratio (OR): 2.86, 95% confidence intervals (95% CI): 1.22-6.70], whereas high intake of eicosapentaenoic acid was inversely related to hay fever (OR: 0.45, 95% CI: 0.22-0.93). Furthermore, high beta-carotene intake increased the risk of hay fever (OR: 1.69, 95% CI: 1.09-2.63) while increasing intake of vitamin E was a protective factor (OR: 0.38, 95% CI: 0.17-0.85). In grouped analyses, the effects of beta-carotene and vitamin E were mainly observed among women and ex-/current-smokers; in these subgroups, linoleic acid increased the risk of hay fever.

CONCLUSIONS

In conclusion, the present results provide further evidence that dietary factors might affect the risk of clinical manifestation of hay fever. However, the effects in smokers and women may suggest different biological mechanisms for the investigated nutrients, which need further research.

A population-based study on variations in the use of adjuvant systemic therapy on postmenopausal patients with early stage breast cancer

PURPOSE

To assess adherence to treatment recommendations regarding adjuvant systemic therapy of postmenopausal patients with early stage breast cancer.

METHODS

A population-based cohort of women from Eastern Thuringia/Germany with first diagnosis of breast cancer in 1995-2000 was studied. The use of adjuvant therapy was assessed separately for patients with positive and negative nodal status fitting polytomous logistic regression models.

RESULTS

Among 396 women with positive lymph nodes and 832 with negative lymph nodes, 92.9% and 87.3% received an adjuvant systemic treatment, respectively. Age, comorbidity, hormone receptor status, histological grading, and additionally, in nodal positives, the number of involved lymph nodes, were associated with treatment patterns. Age had the strongest impact on treatment decision. Older women more often received hormone- or no adjuvant therapy. However, 26.3% of the women with lymph node involvement and positive hormone receptor status received no hormone therapy, whereas 35.7% of women with negative hormone receptor status received hormone therapy.

CONCLUSION

The number of patients with adjuvant systemic therapy is high in women with positive and those with negative lymph nodes, reflecting adherence to the recommendations. Better outcome could be expected if hormone therapy was used adequately in receptor positives. Further follow-up is required to monitor the outcome and changes in adherence to treatment recommendations.

Primary breast cancer therapy in six regions of Germany

Studies from six regions of Germany (Aachen (W1), Dresden (E1), Jena (E2), Marburg (W2), Munich (W3), and Stuttgart (C1)) have been compared to verify and assess the quality of healthcare using breast cancer as an example. All of the data collection was carried out in comprehensive cancer centres and is population-based, with the exception of C1. Classic prognostic factors and the initial treatment of 8661 women with breast cancer, diagnosed between 1996 and 1998, were examined. Primary therapy, breast conserving therapy (BCT), and the use of subsequent local radiation and/or systemic therapy (chemotherapy or hormonal therapy) were analysed. BCT was performed on 39.3-57.7% of patients. By pT-category, the proportion of BCT in the six regions were as follows: for pTis between 37.8 and 64.3%, for pT1 between 51.7 and 71.5%, for pT2 between 25.9 and 51.1%, for pT3 between 0 and 13.1% and for pT4 between 0 and 15.2%. Multivariate analyses, adjusted for age and biological factors, showed a significant influence of the treating hospital on the mastectomy rate. The use of radiotherapy after BCT (80%) was quite homogeneous in the six regions. The application of radiotherapy after mastectomy, however, varied between 10.4 and 32.2%. In all regions, for premenopausal patients, the use of adjuvant systemic therapy almost reflected the St. Gallen-Consensus recommendations. In contrast, post-menopausal women with positive lymph nodes were not always treated according to these standards. In all regions, age had an influence on the administration of treatment: elderly breast cancer patients received less BCT, less radiotherapy and less adjuvant therapy than recommended in the St. Gallen-Consensus. Feedback of the results was made available to each hospital, providing a comparative summary of patient care that could be used by the participating hospitals for self-assessment and quality-control.

Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps

The Ca(2+) concentration and voltage dependence of the relaxation kinetics of the Na-Ca exchanger after a Ca(2+) concentration jump was measured in excised giant membrane patches from guinea pig heart. Ca(2+) concentration jumps on the cytoplasmic side were achieved by laser flash-induced photolysis of DM-nitrophen. In the Ca-Ca exchange mode a transient inward current is generated. The amplitude and the decay rate of the current saturate at concentrations >10 microM. The integrated current signal, i.e., the charge moved is fairly independent of the amount of Ca(2+) released. The amount of charge translocated increases at negative membrane potentials, whereas the decay rate constant shows no voltage dependence. It is suggested that Ca(2+) translocation occurs in at least four steps: intra- and extracellular Ca(2+) binding and two intramolecular transport steps. Saturation of the amplitude and of the relaxation of the current can be explained if the charge translocating reaction step is preceded by two nonelectrogenic steps: Ca(2+) binding and one conformational transition. Charge translocation in this mode is assigned to one additional conformational change which determines the equilibrium distribution of states. In the Na-Ca exchange mode, the stationary inward current depends on the cytoplasmic Ca(2+) concentration and voltage. The K(m) for Ca(2+) is 4 microM for guinea pig and 10 microM for rat myocytes. The amplitude of the pre-steady-state current and its relaxation saturate with increasing Ca(2+) concentrations. In this mode the relaxation is voltage dependent.

The voltage-dependent proton pumping in bacteriorhodopsin is characterized by optoelectric behavior

The light-driven proton pump bacteriorhodopsin (bR) was functionally expressed in Xenopus laevis oocytes and in HEK-293 cells. The latter expression system allowed high time resolution of light-induced current signals. A detailed voltage clamp and patch clamp study was performed to investigate the DeltapH versus Deltapsi dependence of the pump current. The following results were obtained. The current voltage behavior of bR is linear in the measurable range between -160 mV and +60 mV. The pH dependence is less than expected from thermodynamic principles, i.e., one DeltapH unit produces a shift of the apparent reversal potential of 34 mV (and not 58 mV). The M(2)-BR decay shows a significant voltage dependence with time constants changing from 20 ms at +60 mV to 80 ms at -160 mV. The linear I-V curve can be reconstructed by this behavior. However, the slope of the decay rate shows a weaker voltage dependence than the stationary photocurrent, indicating that an additional process must be involved in the voltage dependence of the pump. A slowly decaying M intermediate (decay time > 100 ms) could already be detected at zero voltage by electrical and spectroscopic means. In effect, bR shows optoelectric behavior. The long-lived M can be transferred into the active photocycle by depolarizing voltage pulses. This is experimentally demonstrated by a distinct charge displacement. From the results we conclude that the transport cycle of bR branches via a long-lived M(1)* in a voltage-dependent manner into a nontransporting cycle, where the proton release and uptake occur on the extracellular side.

Interaction of cations, anions, and weak base quinine with rat renal cation transporter rOCT2 compared with rOCT1

The rat organic cation transporter (rOCT)-2 was characterized by electrical and tracer flux measurements compared with rOCT1. By applying choline gradients to voltage-clamped Xenopus oocytes expressing rOCT2, potential-dependent currents could be induced in both directions. Tracer flux measurements with seven organic cations revealed similar Michaelis-Menten constant values for both transporters, with the exception of guanidine. In parallel experiments with rOCT2 and rOCT1, inhibition of tetraethylammonium transport by 12 cations, 2 weak bases, corticosterone, and the anions para-amminohippurate, alpha-ketoglutarate, and probenecid was characterized. The IC(50) values of many inhibitors were similar for both transporters, whereas others were significantly different. Mepiperphenidol and O-methylisoprenaline showed an approximately 70-fold lower and corticosterone a 38-fold higher affinity for rOCT2. With the use of these inhibitors together with previous information on cation transporters, experimental protocols are proposed to dissect out the individual contributions of rOCT2 and rOCT1 in intact proximal tubule preparations. Inhibition experiments at different pH levels strongly suggest that the weak base quinine passively permeates the plasma membrane at physiological pH and inhibits rOCT2 from the intracellular side.

Environmental control of invasin expression in Yersinia pseudotuberculosis is mediated by regulation of RovA, a transcriptional activator of the SlyA/Hor family

Invasin is the primary invasive factor of Yersinia pseudotuberculosis that allows efficient internalization into eukaryotic cells. We investigated invasin expression and found that the inv gene is regulated in response to a variety of environmental signals, such as temperature, growth phase, nutrients, osmolarity and pH, and requires the product of rovA, a member of the SlyA/Hor transcriptional activator family. The rovA gene was found by a genetic complementation strategy that restores temperature regulation of an unexpressed inv-phoA fusion in Escherichia coli K-12. RovA plays a role in the invasion of Y. pseudotuberculosis into mammalian cells and mediates the regulation of invasin in response to all environmental signals analysed. Deletion analysis of the inv promoter region revealed a DNA segment extending 207 bp upstream of the transcriptional start site, which is required for maximal RovA-induced inv transcription. Gel retardation assays showed that RovA interacts preferentially with this promoter fragment and suggested two potential RovA binding sites. Studies with chromosomal gene fusions also demonstrated that rovA follows the same pattern of regulation as invasin, indicating that environmental control of inv expression is mainly mediated by the control of RovA synthesis. Furthermore, we showed that a rovA-lacZ fusion is only slightly expressed in a rovA mutant strain, indicating that a positive autoregulatory mechanism is also involved in rovA expression.

Non-specific activation of the epithelial sodium channel by the CFTR chloride channel

The genetic disease cystic fibrosis is caused by mutation of the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). Controversial studies reported regulation of the epithelial sodium channel (ENaC) by CFTR. We found that uptake of (22)Na(+) through ENaC is modulated by activation of CFTR in oocytes, coexpressing CFTR and ENaC, depending on extracellular chloride concentration. Furthermore we found that the effect of CFTR activation could be mimicked by other chloride channels. Voltage- and patch-clamp measurements, however, showed neither stimulation nor inhibition of ENaC-mediated conductance by activated CFTR. We conclude that the observed modulation of (22)Na(+) uptake by activated CFTR is due to the effect of CFTR-mediated chloride conductance on the membrane potential. These findings argue against the notion of a specific influence of CFTR on ENaC and emphasize the chloride channel function of CFTR.

Electrophysiological characterization of specific interactions between bacterial sensory rhodopsins and their transducers

The halobacterial phototaxis receptors sensory rhodopsin I and II (SRI, SRII) enable the bacteria to seek optimal light conditions for ion pumping by bacteriorhodopsin and/or halorhodopsin. The incoming signal is transferred across the plasma membrane by means of receptor-specific transducer proteins that bind tightly to their corresponding photoreceptors. To investigate the receptor/transducer interaction, advantage is taken of the observation that both SRI and SRII can function as proton pumps. SRI from Halobacterium salinarum, which triggers the positive phototaxis, the photophobic receptor SRII from Natronobacterium pharaonis (pSRII), as well as the mutant pSRII-F86D were expressed in Xenopus oocytes. Voltage-clamp studies confirm that SRI and pSRII function as light-driven, outwardly directed proton pumps with a much stronger voltage dependence than the ion pumps bacteriorhodopsin and halorhodopsin. Coexpression of SRI and pSRII-F86D with their corresponding transducers suppresses the proton transport, revealing a tight binding and specific interaction of the two proteins. These latter results may be exploited to further analyze the binding interaction of the photoreceptors with their downstream effectors.

Expression and NNK reducing activities of carbonyl reductase and 11beta-hydroxysteroid dehydrogenase type 1 in human lung

The tobacco specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK), which is found in high amounts in tobacco products, is believed to play an important role in lung cancer induction in smokers. NNK requires metabolic activation by cytochrome P450 mediated alpha-hydroxylation to exhibit its carcinogenic properties. On the other hand, NNK is inactivated by carbonyl reduction to its alcohol-equivalent 4-methylnitrosamino-1-(3-pyridyl)-1-butanol (NNAL) followed by glucuronidation and final excretion into urine or bile. Carbonyl reduction and alpha-hydroxylation are the predominant pathways in man, and it has been postulated that the extent of these competing pathways determines the individual susceptibility to lung cancer. Moreover, only a minor part of all habitual smokers develop lung cancer, suggesting the existence of susceptibility genes. Microsomal 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD 1) (EC 1.1.1.146) and cytosolic carbonyl reductase (CR) (EC 1.1.1.184) have been shown to be mainly responsible for NNAL formation in liver and lung. In the present study, we performed comparative investigations of human lung tissue samples from several patients with respect to the expression and activity of 11beta-HSD 1 and carbonyl reductase. We observed varying levels in 11beta-HSD 1 and carbonyl reductase expression in these patients, as revealed by RT-PCR and ELISA. Also, the tissue samples showed a different activity and inhibitor profile for both enzymes. According to our results, variations in the expression and activity of NNK carbonyl reducing enzymes may constitute a major determinant in the overall NNK detoxification capacity and thus may be linked to the great differences observed in the individual susceptibility of tobacco-smoke related lung cancer.

Immunohistochemical detection of estrogen and progesterone receptor in human cornea

OBJECTIVE

For treatment of postmenopausal keratoconjunctivitis sicca hormone therapy is favored by some clinicians. The likely morphological basis assessing the hormone receptor status in the human cornea has not been performed. Immunohistochemical staining methods provide the opportunity to evaluate the hormone receptor content within the histologic compartments of the cornea. The aim of our study was to assess and localize immunohistochemical hormone receptor staining in the human cornea.

METHODS

Formalin-fixed and paraffin-embedded specimens of three pre- and three postmenopausal women were assessed for localization of estrogen receptor (ER) and progesterone receptor (PR) expression with established immunohistochemical hormone receptor staining methods.

RESULTS

No nuclear staining reaction was found in the epi- and endothelial layers of the corneas. The stroma of the corneas showed no immunohistochemical staining reaction in all cases. We found cytoplasmatic PR staining of the endothelial layer in two cases.

CONCLUSIONS

We found no morphological basis in the human cornea for the use of topical steroid hormone treatment in postmenopausal keratoconjunctivitis sicca. Hormone receptor expression in the conjunctiva or in the lacrimal gland may have an impact in some patients showing relief of symptoms in postmenopausal dry eye syndrome.

Mechanism of electrogenic cation transport by the cloned organic cation transporter 2 from rat

The organic cation transporter 2 (OCT2) is expressed in plasma membranes of kidney and brain. Its transport mechanism and substrates are debated. We studied substrate-induced changes of electrical current with the patch clamp technique after expression of rat OCT2 in oocytes. Activation of current, corresponding to efflux, was observed for small organic cations, e.g. choline. In contrast, the bigger cations quinine and tetrabutylammonium elicited no change in current. However, transport of choline could be inhibited by applying quinine or tetrabutylammonium to the cytoplasmic side. Inhibition of organic cation efflux by quinine was competitive with substrates. Quinine at the inside also inhibited substrate influx from the outside. Current-voltage analysis showed that both maximal turnover and apparent affinity to substrates are voltage-dependent. Substrate-induced currents with organic cations on both membrane sides reversed as predicted from the Nernst potential. Our results clearly identify the electrochemical potential as driving force for transport at neutral pH and exclude an electroneutral H(+)/organic cation(+) exchange. We suggest the existence of an electroneutral organic cation(+) exchange and propose a model for a carrier-type transport mechanism.

Heterogeneity of 11beta-hydroxysteroid dehydrogenase type 1/microsomal carbonyl reductase (11beta-HSD/CR) in guinea pig tissues. Purification of the liver form suggests modification in the cosubstrate binding site

11beta-hydroxysteroid dehydrogenase (11beta-HSD) and xenobiotic carbonyl reductase activities were determined in guinea pig tissue microsomes. The data indicate the presence of a NADP(H) dependent form, distinct from the known type I isozyme. Purification of 11beta-HSD-1 from liver microsomes resulted in two distinct peaks, resolved by dye-ligand chromatography, indicating differences in the cosubstrate binding site. Immunoblot analysis using anti 11beta-HSD-1 antibodies reveals the presence of similar structural determinants between the enzyme forms. Both have an apparent molecular mass of 32 kDa, suggesting protein modifications occurring in the type 1 isozyme which account for the differences in chromatographic behaviour.

Voltage and substrate dependence of the inverse transport mode of the rabbit Na(+)/glucose cotransporter (SGLT1)

Properties of the cytoplasmic binding sites of the rabbit Na(+)/glucose cotransporter, SGLT1, expressed in Xenopus oocytes were investigated using the giant excised patch clamp technique. Voltage and substrate dependence of the outward cotransport were studied using alpha-methyl D-glucopyranoside (alphaMDG) as a substrate. The apparent affinity for alphaMDG depends on the cytoplasmic Na(+) concentration and voltage. At 0 mV the K(M) for alphaMDG is 7 mM at 110 mM Na(+) and 31 mM at 10 mM Na(+). The apparent affinity for alphaMDG and Na(+) is voltage dependent and increases at positive potentials. At 0 mV holding potential the outward current is half-maximal at about 70 mM. The results show that SGLT1 can mediate sugar transport out of the cell under appropriate concentration and voltage conditions, but under physiological conditions this transport is highly improbable due to the low affinity for sugar.

Differential function of the two nucleotide binding domains on cystic fibrosis transmembrane conductance regulator

The genetic disease cystic fibrosis is caused by defects in the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR). CFTR belongs to the family of ABC transporters. In contrast to most other members of this family which transport substrates actively across a membrane, the main function of CFTR is to regulate passive flux of substrates across the plasma membrane. Chloride channel activity of CFTR is dependent on protein phosphorylation and presence of nucleoside triphosphates. From electrophysiological studies of CFTR detailed models of its regulation by phosphorylation and nucleotide interaction have evolved. These investigations provide ample evidence that ATP hydrolysis is crucial for CFTR gating. It becomes apparent that the two nucleotide binding domains on CFTR not only diverge strongly in sequence, but also in function. Based on previous models and taking into account new data from pre-steady-state experiments, a refined model for the action of nucleotides at two nucleotide binding domains was recently proposed.

Ocular arterial blood flow of choroidal melanoma eyes before and after stereotactic radiotherapy using Leksell gamma knife: 2 year follow up

AIMS

To evaluate the effect of high dose stereotactic radiotherapy on the ocular blood flow of patients with uveal melanoma.

METHODS

Colour Doppler imaging (CDI) was used to measure blood flow velocity and vascular resistance in the ophthalmic, short posterior, and central retinal arteries of nine patients suffering from uveal melanoma. The measurements were taken before, 6 months, 1 year, and 2 years after stereotactic radiotherapy. Irradiation was performed with the Leksell gamma knife with the 59 (41-66.5) Gy total marginal dose divided in two equal fractions. CDI results were compared with age and sex matched healthy control eyes.

RESULTS

At each time of measurement, blood flow velocity in the central retinal artery of the affected eyes was significantly reduced whereas vascular resistance was only increased at the 2 year follow up. Blood flow velocity and vascular resistance in the short posterior arteries of melanoma eyes were also only significantly altered at the 2 year follow up. Blood flow velocity and vascular resistance in the ophthalmic artery of melanoma eyes were not changed at all follow ups.

CONCLUSIONS

In the melanoma eyes, blood flow velocity in the central retinal artery is reduced. High dose stereotactic radiotherapy with the Leksell gamma knife and a 59 (41-66.5) Gy total marginal dose in two fractions leads to a significant reduction of blood flow and a significant increase in resistance variables in the small ocular arteries within 2 years.

Interindividual variability in the expression and NNK carbonyl reductase activity of 11beta-hydroxysteroid dehydrogenase 1 in human lung

The balance between metabolic activation and detoxification is critical in determining the susceptibility to lung cancer upon exposure to the tobacco specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Carbonyl reduction of NNK, followed by glucuronidation, is the main detoxification pathway of this lung carcinogen in humans. Recently, we have identified 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD 1) as microsomal NNK carbonyl reductase in liver and lung. In the present study, the interindividual variability of 11beta-HSD 1 expression and NNK-carbonyl reductase activity was examined in human lung by RT-PCR, Western blot analysis and enzyme activity. Levels of 11beta-HSD 1 mRNA varied over an almost 20-fold range among different subjects. Levels of NNK carbonyl reductase activity in lung microsomes closely resembled the relative amounts of immunoreactive protein as determined by Western blot analysis. In view of the large interindividual differences in the susceptibility of tobacco smoke related lung cancer, we present the first data on the variability of 11beta-HSD 1 expression and NNK carbonyl reduction in human lung.

Retrobulbar hemodynamics in amaurosis fugax; investigation by color Doppler velocity

PURPOSE

The aim of the study is to determine blood flow and resistance parameters (Resistance Index-RI, Pulsatility Index-PI) in the retrobulbar arteries of patients suffering from amaurosis fugax.

METHODS

Color Doppler velocity was used to measure blood flow velocity and vascular resistance in the ophthalmic artery, central retinal artery and lateral short posterior ciliary artery of 32 involved eyes in their afflictless interval. The patients' mean age was 60.1 years (range 29-85). The age- and sexmatched control group comprised 32 healthy volunteers (32 eyes).

RESULTS

There was no significant difference neither in RI nor in PI of amaurosis fugax patients compared to the control group.

CONCLUSIONS

We conclude that in almost all cases of amaurosis fugax no local disturbance of blood flow in the afflictless interval is noted. However, increased vessel resistance is noticed in some cases of amaurosis fugax: Giant cell arteritis, intraorbital vascular anomalies, intraorbital tumors. In these cases color Doppler velocity is able to give information on the extent of blood flow disorder and, in particular by the B-mode, the etiology can be assumed.

Long-term results after surgical basal cell carcinoma excision in the eyelid region

AIMS

To evaluate the data for patients with basal cell carcinoma (BCC) in the eyelid region, to demonstrate histologically controlled tumour excision, and to prove the efficacy of the treatment on the basis of long term observations.

METHODS

Retrospective analysis of 382 microscopically controlled BCC excisions in the eyelid apparatus (350 patients) in a follow up study over 5.7 (SD 1.1) years. Tumour location, tumour size, and histological results were recorded. The same procedure was followed for recurrences. Follow up examinations were carried out 1, 3, 6, and 12 months after the operation, and then annually for a further 4 years or longer.

RESULTS

A recurrence rate of 5.36% was observed after the primary operation. 60.3% of first recurrences occurred in the medial canthus, 41.2% showed in depth extension, and sclerosing types were overly represented at 35.3%. After the second operation the recurrence rate increased to 14.7% and reached 50% after a third and fourth operation.

CONCLUSIONS

The greatest risk of recurrence exists for BCCs of the medial canthus with in depth extension, and for sclerosing types. The recurrence rate increases after every operation. For high risk cases, consideration should be given to adjuvant treatment such as radiotherapy.

[Conjunctival cysts of the orbits: clinical aspects and histology in 4 patients]

BACKGROUND

Only a few reports concerning congenital conjunctival cysts of the orbit (primary nonkeratinized epithelial cysts) have been published.

PATIENTS

We describe four further cases of conjunctival cysts of the orbit, which were observed between 1995 and 1997 in Tübingen and Vienna. Histologically, all cysts were lined by nonkeratinizing epithelium with goblet cells. Epidermal appendages were found in the wall of one cyst. The patients' age was between 1 and 32 years. Clinically, the prominent symptom was swelling of the upper eyelid, persisting in three patients for more than several years. In one patients diplopia and restriction of eye movements developed within several weeks.

CONCLUSIONS

The cases we described are in accordance with the cases reported in the literature. Often a swelling of the upper eyelid persisted for several years, before the cyst has become symptomatic predominantly in an adult patient. In contrast to dermoid or epidermoid cysts, there is no bony erosion and the cysts are located in the superior to nasal orbit. These cysts are probably more common as it is represented in the literature.

Carbonyl reduction of an anti-insect agent imidazole analogue of metyrapone in soil bacteria, invertebrate and vertebrate species

Carbonyl reduction to the respective alcohol metabolites of the anti-insect agent imidazole analogue of metyrapone, NKI 42255 (2-(1-imidazolyl)-1-(4-methoxyphenyl)-2-methyl-1-propanone) and its parent compound metyrapone was characterized in subcellular fractions previously described bacterial and mammalian hydroxysteroid dehydrogenases/carbonyl from soil bacteria, as well as insect, invertebrate and teleost species. The enzymes involved in this metabolic step were characterized with respect to their cosubstrate specificities, inhibitor susceptibilities, and immunological crossreactivities with antibodies directed against reductases (HSD/CR). All fractions investigated rapidly reduced metyrapone, with highest specific activities found in insect, invertebrate and vertebrate fractions. Except for the insect fractions, all species examined reduced the NKI compound. Cosubstrate dependence and inhibitor specificities suggest that the enzymes described belong to the protein superfamilies of short-chain dehydrogenases/reductases (SDR) or aldo-keto reductases (AKR). Immunological crossreactions to the previously established subgroup of HSD/CRs were found in trout liver microsomes and insect homogenates, but not in all bacterial extracts or earthworm microsomes. These findings suggest that the high CR activities found in these fractions belong to different subgroups of SDR or AKR.

Voltage dependence of proton pumping by bacteriorhodopsin is regulated by the voltage-sensitive ratio of M1 to M2

The voltage dependence of light-induced proton pumping was studied with bacteriorhodopsin (bR) from Halobacterium salinarum, expressed in the plasma membrane of oocytes from Xenopus laevis in the range -160 mV to +60 mV at different light intensities. Depending on the applied field, the quenching effect by blue light, which bypasses the normal photo and transport cycle, is drastically increased at inhibiting (negative) potentials, and is diminished at pump current increasing (positive) potentials. At any potential, two processes with different time constants for the M --> bR decay of approximately 5 ms (tau1) and approximately 20 ms (tau2) are obtained. At pump-inhibiting potentials, a third, long-lasting process with tau3 approximately 300 ms at neutral pH is observed. The fast processes (tau1, tau2) can be assigned to the decay of M2 in the normal pump cycle, i.e., to the reprotonation of the Schiff base via the cytoplasmic side, whereas tau3 is due to the decay of M1 without net pumping, i.e., the reprotonation of the Schiff base via the extracellular side. The results are supported by determination of photocurrents induced by bR on planar lipid films. The pH dependence of the slow decay of M1 is fully in agreement with the interpretation that the reprotonation of the Schiff base occurs from the extracellular side. The results give strong evidence that an externally applied electrical field changes the ratio of the M1 and the M2 intermediate. As a consequence, the transport cycle branches into a nontransporting cycle at negative potentials. This interpretation explains the current-voltage behavior of bR on a new basis, but agrees with the isomerisation, switch, transfer model for vectorial transport.

A reevaluation of substrate specificity of the rat cation transporter rOCT1

The substrate specificity of the previously cloned rat cation transporter rOCT1, which is expressed in kidney, liver, and small intestine, was reevaluated. rOCT1 is the first member of a new protein family comprising electrogenic and polyspecific cation transporters that transport hydrophilic cations like tetraethylammonium, choline, and monoamine neurotransmitters. Previous electrical measurements suggested that cations like quinine, quinidine, and cyanine 863, which have been classified as type 2 cations in the liver, are also transported by rOCT1, since they may induce inward currents in rOCT1 expressing Xenopus oocytes (Busch, A. E., Quester, S., Ulzheimer, J. C., Waldegger, S., Gorboulev, V., Arndt, P., Lang, F., and Koepsell, H. (1996) J. Biol. Chem. 271, 32599-32604). Tracer flux measurements with oocytes and with stably transfected human embryonic kidney cells showed that [3H]quinine and [3H]quinidine are not transported by rOCT1. The voltage dependence observed for the quinine- or quinidine-induced inward currents in rOCT1-expressing oocytes, and tracer efflux measurements indicate that the inward currents by type 2 cations are generated by the inhibition of electrogenic efflux of transported type 1 cations. Therefore, rOCT1 cannot contribute to transport of type 2 cations in the liver and the hepatic transporter for type 2 cations remains to be identified.

Na+,K(+)-ATPase pump currents activated by an ATP concentration jump. Comparison of studies with purified membrane fragments and giant excised patches

The lipid bilayer and the giant patch technique were used to study the Na+,K(+)-ATPase. In excised patches from ventricular myocytes, Na+,K(+)-pump currents show a saturable ATP dependence with a Km of approximately 150 microM at 24 degrees C. Partial reactions in the transport cycle were investigated by generating ATP concentration jumps through photolytic release of ATP from caged ATP at pH 7.4 and 6.3. Transient outward currents were obtained at pH 6.3 with a fast rising phase followed by a slow decay to a stationary current. Experiments with purified pig kidney Na+,K(+)-ATPase attached to a planar lipid bilayer resulted in similar pump current signals and the same outcome. It was concluded that the fast rate constant of approximately 200 s-1 at 24 degrees C reflects a step rate limiting the electrogenic Na+ release.

Direct action of genistein on CFTR

Human cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels were expressed in oocytes from Xenopus laevis after injection of CFTR cRNA and studied with the two-electrode voltage-clamp and the giant patch techniques. The tyrosine kinase inhibitor genistein alone activated a small chloride current in whole oocytes expressing CFTR and substantially increased the chloride current obtained upon stimulation with forskolin and isobutyl methylxanthine (IBMX). In giant excised patches, genistein was unable to open protein-kinase-A-phosphorylated CFTR channels in the absence of ATP, but increased the ATP-induced CFTR channel currents by a factor of 3.8 +/- 1.7. This genistein-mediated potentiation in excised patches is independent of protein phosphatase activity, as it is readily reversible, even after complete inhibition of protein kinase A activity. Involvement of protein tyrosine kinases also seems unlikely, because this effect of genistein is not antagonized by high concentrations of the tyrosine phosphatase inhibitor ortho-vanadate. We, therefore, propose a direct interaction of genistein with CFTR, probably at a nucleotide binding site, which leads to a higher open probability.