Within-day energy deficiency and reproductive function in female endurance athletes.

We aimed to estimate and compare within-day energy balance (WDEB) in athletes with eumenorrhea and menstrual dysfunction (MD) with similar 24-hour energy availability/energy balance (EA/EB). Furthermore, to investigate whether within-day energy deficiency is associated with resting metabolic rate (RMR), body composition, S-cortisol, estradiol, T3 , and fasting blood glucose. We reanalyzed 7-day dietary intake and energy expenditure data in 25 elite endurance athletes with eumenorrhea (n = 10) and MD (n = 15) from a group of 45 subjects where those with disordered eating behaviors (n = 11), MD not related to low EA (n = 5), and low dietary record validity (n = 4) had been excluded. Besides gynecological examination and disordered eating evaluation, the protocol included RMR measurement; assessment of body composition by dual-energy X-ray absorptiometry, blood plasma analysis, and calculation of WDEB in 1-hour intervals. Subjects with MD spent more hours in a catabolic state compared to eumenorrheic athletes; WDEB < 0 kcal: 23.0 hour (20.8-23.4) vs 21.1 hour (4.7-22.3), P = .048; WDEB < -300 kcal: 21.8 hour (17.8-22.4) vs 17.6 hour (3.9-20.9), P = .043, although similar 24-hour EA: 35.6 (11.6) vs 41.3 (12.7) kcal/kg FFM/d, (P = .269), and EB: -659 (551) vs -313 (596) kcal/d, (P = .160). Hours with WDEB <0 kcal and <-300 kcal were inversely associated with RMRratio (r = -.487, P = .013, r = -.472, P = .018), and estradiol (r = -.433, P = .034, r = -.516, P = .009), and positively associated with cortisol (r = .442, P = .027, r = .463, P = .019). In conclusion, although similar 24-hour EA/EB, the reanalysis revealed that MD athletes spent more time in a catabolic state compared to eumenorrheic athletes. Within-day energy deficiency was associated with clinical markers of metabolic disturbances.

Effects of RYGB on energy expenditure, appetite and glycaemic control: a randomized controlled clinical trial.

OBJECTIVES: Increased energy expenditure (EE) has been proposed as an important mechanism for weight loss following Roux-en-Y gastric bypass (RYGB). However, this has never been investigated in a controlled setting independent of changes in energy balance. Similarly, only few studies have investigated the effect of RYGB on glycaemic control per se. Here, we investigated the effect of RYGB on EE, appetite, glycaemic control and specific signalling molecules compared with a control group in comparable negative energy balance. SUBJECTS/METHODS: Obese normal glucose-tolerant participants were randomized to receive RYGB after 8 (n=14) or 12 weeks (n=14). The protocol included a visit at week 0 and three visits (weeks 7, 11 and 78) where 24-h EE, appetite and blood parameters were assessed. Participants followed a low-calorie diet from weeks 0-11, with those operated at week 12 serving as a control group for those operated at week 8. RESULTS: Compared with controls, RYGB-operated participants had lower body composition-adjusted 24-h EE and basal EE 3 weeks postoperatively (both P<0.05) but EE parameters at week 78 were not different from preoperative values (week 7). Surgery changed the postprandial response of glucagon-like peptide-1 (GLP-1), peptide YY3-36 (PYY), ghrelin, cholecystokinin, fibroblast growth factor-19 and bile acids (all P<0.05). Particularly, increases in GLP-1, PYY and decreases in ghrelin were associated with decreased appetite. None of HOMA-IR (homeostasis model assessment-estimated insulin resistance), Matsuda index, the insulinogenic index, the disposition index and fasting hepatic insulin clearance were different between the groups, but RYGB operated had lower fasting glucose (P<0.05) and the postprandial glucose profile was shifted to the left (P<0.01). CONCLUSIONS: Our data do not support that EE is increased after RYGB. More likely, RYGB promotes weight loss by reducing appetite, partly mediated by changes in gastrointestinal hormone secretion. Furthermore, we found that the early changes in glycaemic control after RYGB is to a large extent mediated by caloric restriction.

Polybrominated diphenyl ether (PBDE) concentrations and resulting exposure in homes in California: relationships among passive air, surface wipe and dust concentrations, and temporal variability.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam, electronics, and other home furnishings. A field study was conducted that enrolled 139 households from California, which has had more stringent flame retardant requirements than other countries and areas. The study collected passive air, floor and indoor window surface wipes, and dust samples (investigator collected using an HVS3 and vacuum cleaner) in each home. PentaBDE and BDE209 were detected in the majority of the dust samples and many floor wipe samples, but the detection in air and window wipe samples was relatively low. Concentrations of each PBDE congener in different indoor environmental media were moderately correlated, with correlation coefficients ranging between 0.42 and 0.68. Correlation coefficients with blood levels were up to 0.65 and varied between environmental media and age group. Both investigator-collected dust and floor wipes were correlated with serum levels for a wide range of congeners. These two sample types also had a relatively high fraction of samples with adequate mass for reliable quantification. In 42 homes, PBDE levels measured in the same environmental media in the same home 1 year apart were statistically correlated (correlation coefficients: 0.57-0.90), with the exception of BDE209 which was not well correlated longitudinally.

Predictors of serum polychlorinated biphenyl concentrations in Anniston residents.

The Anniston Community Health Survey was a community-based cross-sectional study of Anniston, Alabama, residents who live in close proximity to a former PCB production facility to identify factors associated with serum PCB levels. The survey comprises 765 Anniston residents who completed a questionnaire interview and provided a blood sample for analysis in 2005-2007. Several reports based on data from the Anniston survey have been previously published, including associations between PCB exposure and diabetes and blood pressure. In this study we examine demographic, behavioral, dietary, and occupational characteristics of Anniston survey participants as predictors of serum PCB concentrations. Of the 765 participants, 54% were White and 45% were African-American; the sample was predominantly female (70%), with a mean age of 55 years. Serum PCB concentrations varied widely between participants (range for sum of 35 PCBs: 0.11-170.4 ng/g wet weight). Linear regression models with stepwise selection were employed to examine factors associated with serum PCBs. Statistically significant positive associations were observed between serum PCB concentrations and age, race, residential variables, current smoking, and local fish consumption, as was a negative association with education level. Age and race were the most influential predictors of serum PCB levels. A small age by sex interaction was noted, indicating that the increase in PCB levels with age was steeper for women than for men. Significant interaction terms indicated that the associations between PCB levels and having ever eaten locally raised livestock and local clay were much stronger among African-Americans than among White participants. In summary, demographic variables and past consumption of locally produced foods were found to be the most important predictors of PCB concentrations in residents living in the vicinity of a former PCB manufacturing facility.

Serum concentrations of polychlorinated biphenyls (PCBs) in participants of the Anniston Community Health Survey.

Serum concentrations of 35 ortho-substituted polychlorinated biphenyl congeners (PCBs) were measured in 765 adults from Anniston, Alabama, where PCBs were manufactured between 1929 and 1971. As part of the Anniston Community Health Survey (ACHS), demographic data, questionnaire information, and blood samples were collected from participants in 2005-2007. Forty-six percent of study participants were African-American, 70% were female, and the median age was 56 years. The median concentration of the sum of 35 PCB congeners (ΣPCBs) was 528 ng/g lipid, with a 90th percentile of 2,600 ng/g lipid, minimum of 17.0 ng/g lipid, and maximum of 27,337 ng/g lipid. The least square geometric mean ΣPCBs was more than 2.5 times higher for African-American participants than for White participants (866 ng/g lipid vs. 331 ng/g lipid); this difference did not change materially after adjustment for age, sex, body mass index (BMI) and current smoking. In spite of large differences in absolute PCB levels, relative contributions of individual congeners to ΣPCBs were quite similar between race groups. Nevertheless, while percent contributions to ΣPCBs for most of the most abundant penta- to heptachlorobiphenyls were higher among African-Americans, the percentages were higher in Whites for the lower-chlorinated PCBs 28 and 74 and for octa- to decachlorinated PCBs. No major differences were observed in geometric mean ΣPCBs between women and men when adjusted for age, race, BMI and current smoking (516 ng/g lipid vs. 526 ng/g lipid). Principal component analysis revealed groups of co-varying congeners that appear to be determined by chlorine substitution patterns. These congener groupings were similar between ACHS participants and the National Health and Nutrition Examination Survey (NHANES) 2003-04 sample of the general United States population, despite ACHS participants having serum concentrations of ΣPCBs two to three times higher than those in comparable age and race groups from NHANES.

Fatness predicts decreased physical activity and increased sedentary time, but not vice versa: support from a longitudinal study in 8- to 11-year-old children.

OBJECTIVE: To examine independent and combined cross-sectional associations between movement behaviors (physical activity (PA), sedentary time, sleep duration, screen time and sleep disturbance) and fat mass index (FMI), as well as to examine longitudinal associations between movement behaviors and FMI. METHODS: Cross-sectional and longitudinal analyses were done using data from the OPUS school meal study on 785 children (52% boys, 13.4% overweight, ages 8-11 years). Total PA, moderate-to-vigorous PA (MVPA), sedentary time and sleep duration (7 days and 8 nights) were assessed by an accelerometer and FMI was determined by dual-energy X-ray absorptiometry (DXA) on three occasions over 200 days. Demographic characteristics, screen time and sleep disturbance (Children's Sleep Habits Questionnaire) were also obtained. RESULTS: Total PA, MVPA and sleep duration were negatively associated with FMI, while sedentary time and sleep disturbances were positively associated with FMI (P⩽0.01). However, only total PA, MVPA and sleep duration were independently associated with FMI after adjustment for multiple covariates (P<0.001). Nevertheless, combined associations revealed synergistic effects among the different movement behaviors. Changes over time in MVPA were negatively associated with changes in FMI (P<0.001). However, none of the movement behaviors at baseline predicted changes in FMI (P>0.05), but higher FMI at baseline predicted a decrease in total PA and MVPA, and an increase in sedentary time (P⩽0.001), even in normal-weight children (P⩽0.03). CONCLUSION: Total PA, MVPA and sleep duration were independently associated with FMI, and combined associations of movement behaviors showed a synergistic effect with FMI. In the longitudinal study design, a high FMI at baseline was associated with lower PA and higher sedentary time after 200 days but not vice versa, even in normal-weight children. Our results suggest that adiposity is a better predictor of PA and sedentary behavior changes than the other way around.

Storage of Buffy-coat-derived platelets in additive solutions: in vitro effects on platelets prepared by the novel TACSI system and stored in plastic containers with different gas permeability.

BACKGROUND: The novel TACSI system is designed for automated preparation of platelets (PLTs) from pooled buffy coats (BCs). One TACSI device will handle 6 units at the same time. The aim of our in vitro study is to investigate the effects of using this automated equipment with subsequent storage in two different plastic containers and to compare these results with PLTs prepared by the OrbiSac system. STUDY DESIGN AND METHODS: Buffy-coat-derived PLTs (n=8) were prepared by using the TACSI system, including storage in polyvinyl chloride (PVC)-based plastic containers with di, n-decyl phthalate (DnDP) (TACSI R) and BTHC (TACSI T)-based plasticizers. As a reference, the OrbiSac System was used to prepare PLTs (n=8) with subsequent storage in a PVC plastic container with a citrate-based plasticizer (BTHC). In total, 16 TACSI and eight reference units, supplied by approximately 30% plasma and 70% SSP+, were analysed for various in vitro variables during the 7-day storage period. RESULTS: No significant difference in PLT counts, LDH, mean platelet volume (MPV) and adenosine triphosphate between the groups was detected. Glucose was lower (P<0·05) and lactate was higher (P<0·05) in TACSI R vs. OrbiSac. With exception of day 7 (P<0·05 TACSI R vs. OrbiSac), HSR reactivity were not different between groups. Extent of shape change was lower and CD62P higher in TACSI T when compared with TACSI R and OrbiSac units (P<0·05). pH was maintained at >6·8 (day 7) and swirling remained at the highest level (score=2) for all units throughout storage. CONCLUSION: Platelets prepared by the TACSI system with subsequent storage in two different PVC-based plastic containers were equivalent to reference PLTs with regard to in vitro characteristics during 7 days of storage.

Storage of buffy-coat-derived platelets in additive solutions: in vitro effects on platelets stored in reformulated PAS supplied by a 20% plasma carry-over.

BACKGROUND AND OBJECTIVES: Platelet additive solutions (PAS) have been shown to be suitable for extended platelet (PLT) storage. Depending on the PAS formulation, the percentage of plasma carry-over contributes to success. Improving PLT quality by optimizing the composition of PAS may allow a reduction to be made in the amount of plasma carried over to the final unit. Reducing the proportion of plasma carried over would probably decrease transfusion of unwanted antibodies and make greater amounts of plasma available for other needs. STUDY DESIGN AND METHODS: Platelets from eight pools of 25 buffy coats were aliquoted and prepared for storage in plasma and different PAS units: InterSol and three alternate PAS named PSM1, PSM2 and PSM3. All PAS units were supplied with a 20% plasma carry-over and stored at room temperature with agitation for 9 days with in vitro testing for metabolic, cellular and activation parameters. Results During storage, PLTs stored in InterSol displayed significantly lower glucose concentration (P < 0.01), lower adenosine triphosphate levels (P < 0.01), a higher mean PLT volume (P < 0.01), a lower response to hypotonic shock response activity (P < 0.01) and a higher CD62P expression (P < 0.01) when compared with PLTs stored in plasma and PSM1-3 solutions. pH was maintained at > 6.8 (day 9) and swirling remained at the highest level (score = 2) for all units throughout storage. CONCLUSION: Our results suggest that PLTs stored in PAS with addition of magnesium, potassium and glucose (PSM2 and PSM3) and 20% plasma carry-over maintained metabolic and cellular characteristics, equivalent to PLTs stored in 100% plasma during 9 days of storage. Our results also suggest that presence of potassium in addition to magnesium or alternatively the concentration of phosphate as well as the supply of additional glucose to normal plasma levels improve in vitro data of PLTs stored in PAS.

Adaptive stress response of glutathione and uric acid metabolism in man following controlled exercise and diet.

Ergometer cycling performance as well as acute exercise-induced changes in the metabolism of energy-intermediates and glutathione (GSH) were investigated in skeletal muscle (SM) of 15 healthy young male subjects (VO(2max) approximately 54.7 mL kg(-1) min(-1), age approximately 25 years), before and after 3 days of controlled 'ìoverload-training' in combination with either high (62% of energy intake) or low (26% of energy intake) dietary intake of carbohydrates. The intake of a carbohydrate-rich diet clearly reduced the depletion of SM glycogen following the short-term training period, paralleled with a positive effect on the endurance performance, but not on high-intensity work-performance. An 'delayed over-reaching effect', defined as impaired work-performance, was observed after 2.5 days of recovery from the short-term training period, irrespective of the carbohydrate content of the diet and basal glycogen level in SM. Taken together, the main and novel findings of present investigation are: (1) an acute decrease of reduced GSH content and altered thiol-redox homeostasis in SM induced by strenuous high-intensity exercise; (2) an adaptive elevation of basal GSH level following the short-term training period; (3) an adaptive decrease of basal GSH level following 2.5 days recovery from training; (4) evidence of a relationship between the SM fibre type, physical performance capacity and GSH turnover during acute bouts of exercise; and (5) no evident effect of the level of carbohydrate intake on metabolism of GSH or energy intermediates. Furthermore, the induction of acute oxidative stress in exercising human SM and the adaptive responses to training are suggested to provide a protective antioxidant phenotype to the exercising SM during periods with repeated intense intermittent training.

Enhanced potency of human Sonic hedgehog by hydrophobic modification.

Post-translational modifications of the developmental signaling protein Sonic hedgehog (Shh) by a long-chain fatty acid at the N-terminus and cholesterol at the C-terminus greatly activate the protein in a cell-based signaling assay. To investigate the structural determinants of this activation phenomenon, hydrophobic and hydrophilic moieties have been introduced by chemical and mutagenic methods to the soluble N-terminal signaling domain of Shh and tested in both in vitro and in vivo assays. A wide variety of hydrophobic modifications increased the potency of Shh when added at the N-terminus of the protein, ranging from long-chain fatty acids to hydrophobic amino acids, with EC(50) values from 99 nM for the unmodified protein to 0.6 nM for the myristoylated form. The N-myristoylated Shh was as active as the natural form having both N- and C-terminal modifications. The degree of activation appears to correlate with the hydrophobicity of the modification rather than any specific chemical feature of the adduct; moreover, substitution with hydrophilic moieties decreased activity. Hydrophobic modifications at the C-terminus of Shh resulted in only a 2-3-fold increase in activity, and no activation was found with hydrophobic modification at other surface positions. The N-terminal modifications did not appear to alter the binding affinity of the Shh protein for the transfected receptor protein, Patched, and had no apparent effect on structure as measured by circular dichroism, thermal denaturation, and size determination. Activation of Desert Hh through modification of its N-terminus was also observed, suggesting that this is a common feature of Hh proteins.

Immunohistochemical profiles of 30 monoclonal antibodies against cytokeratins 8, 18 and 19. Second report of the TD5 workshop.

In the first report of the TD5 workshop (TD5-1), the epitope specificities of 30 different monoclonal antibodies against cytokeratins 8, 18 and 19 were determined. This second report presents the immunohistochemical profiles of these antibodies using human appendix and normal skin for evaluation. Each antibody was tested by one or two different laboratories recruited from the Dutch Working Group on Immunohistochemistry and Cytochemistry. Eight different laboratories participated. The histological specimens were pretreated by the participants in three different ways for immunohistochemistry: microwave antigen retrieval in citrate buffer, enzymatic digestion to restore epitope exposure, no specific treatment (untreated paraffin-embedded samples), and tested blindly without knowledge of cytokeratin or epitope specificity of the antibodies at three different concentrations of 50, 10 and 1 microg/ml. Most of the tested antibodies (29/30) were useful in at least one pretreatment method, with microwave antigen retrieval being the most sensitive approach. For some antibodies, very high backgrounds were observed. Furthermore, it can be concluded that 11 MAbs performed well using all three staining protocols, including untreated paraffin-embedded sections. Interestingly, all the antibodies with documented selected specificity towards cytokeratin 8 (i.e. 178, 191, 199, 202 and 206) are reactive with an immunodominant region corresponding to amino acids 340-365 on cytokeratin 8, which evidently is well-suited as target for immunohistochemical interactions. Similarly, three antibodies with the same capacity to react with untreated samples had specificity against cytokeratin 19 (i.e. 179, 197 and 204) in the corresponding region in this filament, i.e. amino acids 311-335, or the KS 19.1 epitope. None of the six antibodies against the other major cytokeratin 19 epitope (BM 19.21) were found useful for immunohistochemistry on untreated samples. The overall conclusions from the present investigation are that all cytokeratin-8-specific antibodies with defined epitope specificities were very useful. Only one of the major two epitopes on cytokeratin 19 seems to be available for efficient immunohistochemistry. Cytokeratin 18 exposes some epitopes outside the immunodominant region reactive with the antibodies 190, 203 and 205 which can be used for untreated samples. The implications of these findings are of significance both for diagnostic histopathology and for the biology of tumor marker epitope expression in tissues.

Effect of protein intake and physical activity on 24-h pattern and rate of macronutrient utilization.

Effects of moderate physical activity (90 min at 45-50% of maximal O2 uptake 2 times daily) and "high" (2.5 g protein. kg-1. day-1, n = 6) or "normal" protein intake (1.0 g protein. kg-1. day-1, n = 8) on the pattern and rate of 24-h macronutrient utilization in healthy adult men were compared after a diet-exercise-adjustment period of 6 days. Energy turnover (ET) was determined by indirect and direct (suit) calorimetry, and "protein oxidation" was determined by a 24-h continuous intravenous infusion of [1-13C]leucine. Subjects were in slight positive energy balance during both studies. Protein contributed to a higher (22 vs. 10%) and carbohydrate (CHO) a lower (33 vs. 58%) proportion of total 24-h ET on the high- vs. normal-protein intake. The highest contribution of fat to ET was seen postexercise during fasting (73 and 61% of ET for high and normal, respectively). With the high-protein diet the subjects were in a positive protein (P < 0.001) and CHO balance (P < 0.05) and a negative fat balance (P < 0.05). The increased ET postexercise was not explained by increased rates of urea production and/or protein synthesis.

Epitope specificity of 30 monoclonal antibodies against cytokeratin antigens: the ISOBM TD5-1 Workshop.

The epitope specificities of 30 monoclonal antibodies (MAbs) against the most common human cytokeratins. i.e., Nos. 8, 18, and 19, in epithelial cells were investigated in the ISOBM TD-5 Workshop. Seven research groups from universities or companies participated independently in the evaluation of the antibody specificities. The complex assembly of cytokeratins in vivo, with obligatory heterologous dimeric combinations of different cytokeratins from each of the two major groups, comprising together more than 20 different individual cytokeratins, made analysis of the antibody reactivity patterns with isolated single cytokeratins necessary. The concordance of the evaluations was striking and independent of the technologies used. As antigens purified individual cytokeratins, chemically degraded purified cytokeratins, recombinant intact and truncated cytokeratins, as well as specific synthesized shorter peptides were used. In order to elucidate the epitope specificity, reactivity patterns in ELISA assays and immunoblots with partial enzymatic degradation of the antigens were performed. Competitive cross-inhibition experiments between antibodies using antigens and antibodies in all possible combinations were performed with radioimmunometric assays, BIAcore, and ELISA technology. All 30 antibodies could convincingly be classified with regard to target cytokeratin. One MAb (192) had to be deleted due to dual specificities in both isotype and epitope specificity against its target. Six antibodies bound selectively to cytokeratin 8, 14 to cytokeratin 18, and 10 to cytokeratin 19, as demonstrated by using native, recombinant, and synthesized antigens. The immunodominant part of the molecule for all three types of cytokeratins was located in the region of amino acid (aa) 270-400. Out of the six MAbs reactive with cytokeratin 8, four MAbs, i.e., 178, 199, 202, and 206, were reactive with a sequence in the interval aa 340-365, and MAb 191 reacted with a closely related epitope. The remaining antibody, 192, presented dual specificities. At least two closely related major immunogenic epitopes could be identified in cytokeratin 8. In cytokeratin 18 four distinct epitopes could be documented, again with the dominating sequence region 270-429 as target for 10 (181, 184, 186, 188, 189, 190, 193, 196, 198, and 200) out of 14 antibodies. Since MAb 193 is known to react with the M3 epitope, aa 322-342 in cytokeratin 18, this entire group is reactive in the region close to the charge shift, in the middle of the rod 2B region, as shown by competitive binding. The remaining four anticytokeratin 18 antibodies (180, 185, 203, and 205) displayed unique, noncompetitive binding to this filament. Cytokeratin 19, reactive with altogether ten antibodies, displayed two major epitopes, all of them also within the large immunodominant region. MAbs 179, 195, 197, and 204 were reactive with the peptides aa 311-335 also known as the KS 19.1 epitope, and MAbs 182, 183, 187, 194, and 201 bound to peptide aa 346-367, known as the BM 19.21 epitope. One antibody, 231, was selectively reactive with aa 356-370 in cytokeratin 19. A complex pattern of binding specificities comprising at least ten different, noncompetitive epitopes, mainly situated in the rod portion, 2A and 2B, situated close to the charge shift in the rod of all three cytokeratins was documented. Out of the 29 classifiable antibodies, altogether 22 were reactive in this very short region, i.e., from aa 311 to 370 in all cytokeratin filaments. The remaining seven antibodies displayed unique binding properties. The implications of the findings are of significance both for immunohistochemistry and for assaying circulating heterodimeric, partially degraded complexes in patients' blood for tumor marker evaluation.

A potential role of R-cadherin in striated muscle formation.

We have examined the murine embryonic expression pattern of the cell adhesion molecule R-cadherin in muscle, kidney, thymus, and lung. In developing muscle, R-cadherin was first seen at 10.5-11.5 days postcoitum in the somitic myotome. Consistently, we found R-cadherin expressed at the highest levels in the myotome, early skeletal muscle, and smooth muscle (both vascular and visceral), while very low levels of R-cadherin were detected in the heart. The expression pattern and subcellular localization of R-cadherin in developing skeletal muscle indicate a possible role in myoblast cell-cell interactions during both primary and secondary myogenesis. In the developing kidney, R-cadherin was first detected at 10.5 days postcoitum in the mesonephric epithelial tubule cells. In the metanephric kidney, it was specifically expressed in the pretubular aggregates, comma- and S-shaped bodies, proximal tubules, and collecting ducts. Thus, in the kidney, R-cadherin was associated with the mesenchymal-epithelial transition. R-cadherin was also found in other developing epithelia, for example in the thymic epithelial cells. In the lung, R-cadherin was expressed at the highest levels in the smooth muscle surrounding the lung epithelial tubules. To test whether R-cadherin can direct formation of tissues, we constitutively expressed R-cadherin in E-cadherin-/- ES cells and examined histogenesis in teratomas derived from these cells. R-cadherin exclusively rescued formation of striated muscle and epithelia in the teratomas. R-cadherin's ability to form epithelia in vivo was substantiated by its ability to rescue formation of cystic embryoid bodies in vitro. By comparing our data with the previously reported embryonic expression patterns and histogenetic activities of E- and N-cadherin, we suggest that R-cadherin plays an important role in the formation of striated muscle and possibly also of epithelia.

Determination of chlorinated pesticides and PCB in pine needles - improved method for the monitoring of airborne organochlorine pollutants.

A method to determine organochlorine pollutants in pine needles is described. Fresh, whole needles have been extracted for 48 h in dichloromethane to obtain the epicuticular wax fraction. The remainder has been cut into small pieces and again extracted with dichloromethane to obtain the internal lipids. Prior to gas chromatography, both the wax and the internal lipid extracts have been fractionated on two columns: first a silica gel/silica gel : sulphuric acid 2 : 1 column with dichloromethane as eluent and then a nitrophenyl silica column with hexane as eluent. Three fractions have been collected, fraction 1 containing hexachlorobenzene (HCB), fraction 2 containing polychlorinated biphenyls (PCB) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE), and fraction 3 containing the remaining, more polar, organochlorine pesticides. For some pine species, the nitrophenyl silica column has been combined with a short aminopropyl silica column to obtain chromatograms of the PCB fraction free from negative peaks. The precision is in the range of 4-12% relative standard deviation, and the overall recovery is around 65-90%.