Identification of a female murder victim found in Burgenland, Austria in 1993

In 1993, the skeletal remains of a female corpse were found in Burgenland, Austria. Initial identification of the approximately 25–35-year-old female appeared impossible, but the case was reopened 23 years later. By applying biogeochemical isotope methods to her body tissues, the geographical origin of the unknown corpse could be predicted. The results of the C, N, S, H, Sr, and Pb isotope analyses suggested that the female did not originate from Europe and most likely spent her youth in the northern Caribbean. Using these findings, the police were able to identify the woman within 2 weeks. The female came from the Dominican Republic and resided in Austria for only a short period before she was murdered. This case shows that isotope biogeochemistry investigations can provide the police with crucial information that enables unknown persons to be identified.

Keypoints

C-N-S-H and Sr-Pb isotope analyses were applied to human remains associated with a cold case.

It was possible to determine the region of origin of the unknown deceased individual as the northern Caribbean.

After 23 years, the murder victim was successfully identified.

Stable isotope relationships between apatite phosphate (δ18 O), structural carbonate (δ18 O, δ13 C), and collagen (δ2 H, δ13 C, δ15 N, δ34 S) in modern human dentine

RATIONALE

The use of multi-isotopic analysis (δ² H, δ¹³ C, δ¹⁵ N, δ¹⁸ O, and δ³⁴ S values) of modern human body tissues for provenancing of unknown individuals in forensics is increasing. Tooth dentine develops during childhood and adolescence, therefore providing geographical information from that period of life. Tooth apatite δ¹⁸ O values are commonly used for the reconstruction of drinking water values, and H-C-N-S isotope ratios in collagen supply additional information about the composition of diet. We tested if dentine collagen δ² H values provide similar information to apatite δ¹⁸ O values with a proof-of-concept study.

METHODS

Tooth samples were taken from modern-day individuals born in different regions of the world. Apatite and collagen were prepared from dentine. Stable isotope analyses were performed on apatite phosphate oxygen (δ¹⁸ O_phos ); oxygen and carbon of the structural carbonate (δ¹⁸ O_carb , δ¹³ C_carb ); and hydrogen, carbon, nitrogen, and sulfur of the collagen (δ² H_coll, δ¹³ C_coll , δ¹⁵ N, δ³⁴ S).

RESULTS

δ¹⁸ O_phos , δ¹⁸ O_carb , and δ² H_coll values are highly correlated in modern human dentine. There are significant relationships of δ¹⁸ O values in the apatite fraction and δ² H values in the collagen fraction with local δ¹⁸ O and δ² H precipitation values, respectively. Pearson correlation coefficients indicate no direct relationship between δ¹⁵ N values and the isotope ratios of any other element. Weak relationships exist between collagen δ³⁴ S values and δ¹⁸ O_carb or δ¹⁸ O_phos values.

CONCLUSIONS

The highly significant correlation of δ¹⁸ O_phos , δ¹⁸ O_carb , and δ² H_coll values in the modern human dentine implies that measurement of δ² H values in collagen or δ¹⁸ O values in bioapatite will provide reliable information about the climate at the person's whereabouts.

Stable Carbon Isotope Ratio Analysis of Honey: Validation of Internal Standard Procedure for Worldwide Application

Stable carbon isotope ratio analysis (SCIRA) of honey for undeclared presence of cane or corn sugars has been available for 20 years. Its use with domestic and imported honeys is reviewed. Six years of data from the internal standard isotope ratio analysis (ISCIRA) method support its worldwide validity for honey analysis. The ISCIRA database of pure honeys has been increased from 64 U.S. samples to 224 by addition of data from Germany, United Kingdom, Mexico, Italy, and Spain. ISCIRA analyses of 131 commercial honeys from the United States, Mexico, and Spain found that 17 are adulterated. Analyses of 303 Chinese honeys proves that they should have carbon isotope values similar to honeys from other areas, contrary to claims that the observed differences are intrinsic because of the variability of environmental conditions and of plants used in honey production in China. Addition of corn or cane (C4) sugars to honeys in amounts that do not produce a δ13C value greater than -23.5%o for the mixture cannot be detected by the original 1978 SCIRA procedure. Such adulteration however is detected by ISCIRA procedure from the δ13C value of the protein contained in the honey, which shows the isotopic composition of the honey before addition of C4 sugars. Fortythree percent of 98 honeys received in the United States in 1994-1997 with δ13C < -23.5%o were suspected and found to be adulterated.

Determination of the 13C/12C Ratio of Ethanol Derived from Fruit Juices and Maple Syrup by Isotope Ratio Mass Spectrometry: Collaborative Study

A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quantitative yield (>96%). The carbon-13 deviation (δ13C) of ethanol is then determined by IRMS. This parameter becomes less negative when exogenous sugar derived from plants exhibiting a C4 metabolism (e.g., corn or cane) is added to a juice obtained from plants exhibiting a C3 metabolism (most common fruits except pineapple) or to maple syrup. Conversely, the δ13C of ethanol becomes more negative when exogenous sugar derived from C3 plants (e.g., beet, wheat, rice) is added to pineapple products. Twelve laboratories analyzed 2 materials (orange juice and pure cane sugar) in blind duplicate and 4 sugar-adulterated materials (orange juice, maple syrup, pineapple juice, and apple juice) as Youden pairs. The precision of that method for measuring δ13C was similar to that of other methods applied to wine ethanol or extracted sugars in juices. The within-laboratory (sr) values ranged from 0.06 to 0.16‰ (r = 0.17 to 0.46‰), and the among-laboratories (sR) values ranged from 0.17 to 0.26‰ (R = 0.49 to 0.73‰). The Study Directors recommend that the method be adopted as First Action by AOAC INTERNATIONAL.

PET imaging of chemokine receptor CXCR4 in patients with primary and recurrent breast carcinoma

Background

CXCR4 is a chemokine receptor frequently overexpressed in invasive breast cancer that has been shown to play a major role in signaling pathways involved in metastasis. The aim of this retrospective analysis was to assess the diagnostic performance of CXCR4-directed PET imaging in patients with breast cancer using the recently introduced CXCR4-targeted PET probe ⁶⁸Ga-Pentixafor.

Results

Thirteen patients with first diagnosis of breast cancer, four patients with recurrent disease after primary breast cancer, and one patient with axillary lymph node metastasis of unknown primary underwent CXCR4-targeted PET imaging using ⁶⁸Ga-Pentixafor. Maximum standardized uptake values (SUVmax) and tumor-to-background (T/B) ratios of tumor lesions were measured and compared with pathological prognostic factors and molecular subtypes. ¹⁸F-FDG PET/CT images were available in 8/18 cases and were compared semi-quantitatively. Comparison with CXCR4 expression determined by immunohistochemistry was performed in 7/18 patients.

Nine of 13 primary breast cancers were visually detectable on ⁶⁸Ga-Pentixafor PET images (mean SUVmax of 3.0). The visually undetectable lesions included both cases of invasive lobular carcinoma (ILC) and two cases of invasive carcinoma of no special type (NST) without any hormone receptor and HER2 expression (triple negative). Metastases of recurrent breast cancer and unknown primary cancer were visually detectable in all five cases, exhibiting a mean SUVmax of 3.5. ¹⁸F-FDG PET demonstrated higher SUVmax in all patients compared to ⁶⁸Ga-Pentixafor PET. A correlation between SUVmax obtained from ⁶⁸Ga-Pentixafor PET and prognostic factors including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) status, proliferation index, tumor grade, or molecular subtypes was not observed.

Conclusions

CXCR4-directed PET imaging in patients with primary and recurrent breast cancer is feasible; however, tumor detectability is significantly lower compared to ¹⁸F-FDG PET. Moreover, we did not find any correlation between aforementioned prognostic factors of breast cancer and CXCR4-targeted tracer accumulation. Based on these results in a small patient cohort, CXCR4-targeted PET imaging does not seem to be suitable as a general diagnostic tool for imaging of breast cancer. Future CXCR4 imaging studies should investigate whether this modality might be useful in more specific applications, e.g., in therapeutic approaches especially under the view of current developments in targeted immune cell and immune checkpoint inhibitory therapy.

Global spatial distributions of nitrogen and carbon stable isotope ratios of modern human hair

RATIONALE

Natural stable carbon (δ(13)C) and nitrogen isotope ratios (δ(15)N) of humans are related to individual dietary habits and environmental and physiological factors. In forensic science the stable isotope ratios of human remains such as hair and nail are used for geographical allocation. Thus, knowledge of the global spatial distribution of human δ(13)C and δ(15)N values is an essential component in the interpretation of stable isotope analytical results.

METHODS

No substantial global datasets of human stable isotope ratios are currently available, although the amount of available (published) data has increased within recent years. We have herein summarised the published data on human global δ(13)C andδ(15)N values (around 3600 samples) and added experimental values of more than 400 additional worldwide human hair and nail samples. In order to summarise isotope ratios for hair and nail samples correction factors were determined.

RESULTS

The current available dataset of human stable isotope ratios is biased towards Europe and North America with only limited data for countries in Africa, Central and South America and Southeast Asia. The global spatial distribution of carbon isotopes is related to latitude and supports the fact that human δ(13)C values are dominated by the amount of C4 plants in the diet, either due to direct ingestion as plant food, or by its use as animal feed. In contrast, the global spatial distribution of human δ(15)N values is apparently not exclusively related to the amount of fish or meat ingested, but also to environmental factors that influence agricultural production.

CONCLUSIONS

There are still a large proportion of countries, especially in Africa, where there are no available data for human carbon and nitrogen isotope ratios. Although the interpretation of modern human carbon isotope ratios at the global scale is quite possible, and correlates with the latitude, the potential influences of extrinsic and/or intrinsic factors on human nitrogen isotope ratios have to be taken into consideration.

A stable isotope approach to assessing water loss in fruits and vegetables during storage

Plant tissue water is the source of oxygen and hydrogen in organic biomatter. Recently, we demonstrated that the stable hydrogen isotope value (δ(2)H) of plant methoxyl groups is a very reliable and easily available archive for the δ(2)H value of this tissue water. Here we show in a model experiment that the δ(2)H values of methoxyl groups remain unchanged after water loss during storage of fruits and vegetables under controlled conditions, while δ(2)H and δ(18)O values of tissue water increase. This enhancement is plant-dependent, and the correlation differs from the meteoric water line. The δ(18)O value is better correlated to the weight decrease of the samples. Therefore, we postulate that the δ(2)H value of methoxyl groups and the δ(18)O value of tissue water are suitable parameters for checking postharvest alterations of tissue water, either addition or loss.

Does natural weathering change the stable isotope composition (²H, ¹³C, ¹⁵N, ¹⁸O and ³⁴S) of cattle hair?

Stable isotope analysis of hair has found applications in many fields of science because it provides a temporally resolved, fairly stable isotopic archive of mammalian individuals. We investigated whether this hair archive is modified by natural weathering while attached to a living animal. We analyzed the tail switch hairs of one suckler cow, sampled seven times over a period of four annual summer pasture-winter stall feeding cycles. We compared relative isotope ratios (δ²H, δ¹³C, δ¹⁵N, δ¹⁸O and δ³⁴S) of sections of hair that grew simultaneously but were exposed to natural weathering conditions over different periods of time. Natural wear caused a loss of mass of approx. 0.13% day⁻¹, with no apparent effect of environmental conditions. Changes in δ²H, δ¹³C, δ¹⁵N and δ¹⁸O were below the detection limit, indicating that hair is a reliable archive for the isotopes of these elements. In contrast, δ³⁴S values increased during the grazing period by about 1‰, with exposure to UV radiation appearing to have a major influence on this result. The δ³⁴S values decreased during the subsequent stall period, probably due to abrasion. Seasonal variation in δ³⁴S may indicate alternating environments that differ in their weathering conditions.

Essential methodological improvements in the oxygen isotope ratio analysis of N-containing organic compounds

The quantitative conversion of organically bound oxygen into CO, a prerequisite for the (18)O/(16)O analysis of organic compounds, is generally performed by high-temperature conversion in the presence of carbon at ∼1450°C. Since this high-temperature procedure demands complicated and expensive equipment, a lower temperature method that could be utilized on standard elemental analyzers was evaluated. By substituting glassy carbon with carbon black, the conversion temperature could be reduced to 1170°C. However, regardless of the temperature, N-containing compounds yielded incorrect results, despite quantitative conversion of the bound oxygen into CO. We believe that the problems were partially caused by interfering gases produced by a secondary decomposition of N- and C-containing polymers formed during the decomposition of the analyte. In order to overcome the interference, we replaced the gas chromatographic (GC) separation of CO and N(2) by reversible CO adsorption, yielding the possibility of collecting and purifying the CO more efficiently. After CO collection, the interfering gases were vented by means of a specific stream diverter, thus preventing them from entering the trap and the mass spectrometer. Simultaneously, a make-up He flow was used to purge the gas-specific trap before the desorption of the CO and its subsequent mass spectrometric analysis. Furthermore, the formation of interfering gases was reduced by the use of polyethylene as an additive for analytes with a N:O ratio greater than 1. These methodological modifications to the thermal conversion of N-containing analytes, depending on their structure or O:N ratio, led to satisfactory results and showed that it was possible to optimize the conditions for their individual oxygen isotope ratio analysis, even at 1170°C. With these methodological modifications, correct and precise δ(18)O results were obtained on N-containing analytes even at 1170°C. Differences from the expected standard values were below ±1‰ with standard deviations of the analysis <0.2‰.

Isotopic and elemental data for tracing the origin of European olive oils

H, C, and O stable isotope ratios and the elemental profile of 267 olive oils and 314 surface waters collected from 8 European sites are presented and discussed. The aim of the study was to investigate if olive oils produced in areas with different climatic and geological characteristics could be discriminated on the basis of isotopic and elemental data. The stable isotope ratios of H, C, and O of olive oils and the ratios of H and O of the relevant surface waters correlated to the climatic (mainly temperature) and geographical (mainly latitude and distance from the coast) characteristics of the provenance sites. It was possible to characterize the geological origin of the olive oils by using the content of 14 elements (Mg, K, Ca, V, Mn, Zn, Rb, Sr, Cs, La, Ce, Sm, Eu, U). By combining the 3 isotopic ratios with the 14 elements and applying a multivariate discriminant analysis, a good discrimination between olive oils from 8 European sites was achieved, with 95% of the samples correctly classified into the production site.

Multielement (H, C, N, O, S) stable isotope characteristics of lamb meat from different Italian regions

The study focuses on the (2)H/H, (13)C/(12)C, (15)N/(14)N, (18)O/(16)O and (34)S/(32)S values of defatted dry matter (DFDM) and on the (2)H/H, (13)C/(12)C and (18)O/(16)O values of the fat fraction of meat samples from various lamb types reared in seven Italian regions, following different feeding regimes (forage, concentrate, milk). The (13)C/(12)C (r = 0.922), (2)H/H (r = 0.577) and (18)O/(16)O (r = 0.449) values of fat and DFDM are significantly correlated, the fat values being significantly lower for C and H and higher for O than for DFDM values and the differences between the two fractions not being constant for different lamb types. The feeding regime significantly affected the (13)C/(12)C, (15)N/(14)N, (18)O/(16)O and (2)H/H of fat. The DFDM (2)H/H, and (18)O/(16)O values, excluding an outlier, are significantly correlated with the corresponding values in meteoric waters, thus allowing us to trace the variability of geoclimatic factors. (15)N/(14)N is influenced by pedoclimatic conditions, whereas (34)S/(32)S is influenced by the sea spray effect and the surface geology of the provenance area. By applying stepwise linear discriminant analysis only the (2)H/H of fat was found not to be significant and 97.7% of the samples were correctly assigned to the lamb type and more than 90% cross-validated. With the feeding regime, 97.7% of the samples were both correctly assigned and cross-validated using a predictive model including (13)C/(12)C, (15)N/(14)N, (18)O/(16)O, (34)S/(32)S of DFDM and (18)O/(16)O of fat.

Coast and year effect on H, O and C stable isotope ratios of Tyrrhenian and Adriatic Italian olive oils

The paper discusses the (2)H/(1)H, (18)O/(16)O and (13)C/(12)C ratios of 196 authentic Italian extra-virgin olive oils produced in 3 years on the Tyrrhenian and Adriatic coasts. The (2)H/(1)H and (18)O/(16)O ratios were linearly and positively correlated. The year of production influenced mainly (18)O/(16)O in relation to the amount of rainfall and the atmospheric humidity in the period of oil accumulation in the olives. The (2)H/(1)H ratio significantly distinguished the olive oils produced on the Adriatic coast from those on the Tyrrhenian coast in each year. This coast effect is a consequence of the different sources and isotopic compositions of the rainfall and the different climatic conditions on the two coasts. The paper contributes towards understanding the influence of climatic factors on isotopic variability and towards improving the traceability of the geographical origin of olive oils, using (2)H/(1)H as a more innovative parameter.

Multi-element (H,C,N,S) stable isotope characteristics of lamb meat from different European regions

Multi-element (H,C,N,S) stable isotope ratio analysis was tested for its suitability as a means for geographical provenance assignment of lamb meat from several European regions. The defatted dry matter (crude protein fraction) from lamb meat was found to be a suitable probe for "light" element stable isotope ratio analysis. Significant differences were observed between the multi-element isotope ratios of lamb samples from different regions. The mean hydrogen isotopic ratios of the defatted dry matter from lamb were found to be significantly correlated with the mean hydrogen isotopic ratios of precipitation and groundwater in the production regions. Carbon and nitrogen isotopic ratios were influenced by feeding practices and climate. Sulfur isotopic ratios were influenced by geographical location and surface geology of the production region. The results permitted differentiation of lamb meat, from most production regions, by inspection. However, more sophisticated evaluation of the data using multivariate methods, such as linear discriminant analysis, achieved 78% correct classification.

Correlation Between Multielement Stable Isotope Ratio and Geographical Origin in Peretta Cows’ Milk Cheese

The aim of this study was to characterize the isotopic composition and protect "Peretta" cows' milk cheese, a typical product of Sardinia, against other cheeses of the same appearance sold under the same name, but made of raw materials from northern Europe. The study was concerned with 3 types of cheese: those produced in local dairies from milk from free-grazing or pasture-grazing cows in Sardinia (local dairy product), cheeses made on an industrial scale from milk produced by intensive farming in Sardinia (factory cheese), and cheeses made with raw materials imported from other countries (imported product). To distinguish the Sardinian cheeses from the imported product, the stable isotope ratios 13C/12C, 15N/14N, D/H, 34S/32S, and (18)O/(16)O were used. Determination of the isotopic data delta13C, delta15N, delta2H, and delta34S was performed in the casein fraction, whereas delta(18)O and delta13C were determined in the glycerol fraction. Measurements were performed by isotope ratio mass spectrometry. A comparison between mean values of the isotope ratios by statistical analysis (ANOVA and Tukey's test) showed that the greatest difference between the 3 types of cheese (local dairy, factory, and imported products) was in the 13C/12C, 34S/32S, and (18)O/(16)O isotope ratios. In the other parameters, either no differences (delta15N) or minimal differences (delta2H) were found. Evaluation of the data by multivariate statistical analysis (principal component analysis and hierarchical cluster analysis) revealed that the isotope characteristics of the factory products were similar to those of the cheeses produced from imported raw materials, whereas a difference was found between the local dairy-produced cheeses and the products in the other 2 categories.

Influence of the distillation step on the ratios of stable isotopes of ethanol in cherry brandies

Isotope ratio mass spectrometry and site-specific natural isotope fractionation-nuclear magnetic resonance were applied to determine the overall carbon isotope ratio (delta13C) and the hydrogen isotope ratios [(D/H)I and (D/H)II] of ethanol, respectively. Ethanol was obtained by distillation of fermented cherry mash from a pot still commonly used in fruit brandy production. Analyses of distillate fractions revealed that the distillation proceeds with a fractionation of ethanol isotopologues. The inverse vapor pressure isotope effect (VPIE) observed for the carbon isotopologues is in accordance with the data reported for distillation of ethanol in spinning band columns. In contrast, the inverse VPIE for hydrogen isotopologues of ethanol observed in spinning band columns could not be confirmed. To investigate whether the observed isotope fractionations might influence the applicability of stable isotope analysis for quality and authenticity assessment of fruit brandies, the collected distillate fractions were recombined to cuts, as is common practice in commercial fruit brandy production. Taking into consideration the limits of repeatability of the method, it could be demonstrated that the isotope fractionations observed do not impair the applicability of stable isotope analysis of the carbon and hydrogen isotopes of ethanol for the authenticity assessment of cherry brandies if the cuts are placed in accordance with common distillers' practice.

Detection of royal jelly adulteration using carbon and nitrogen stable isotope ratio analysis

Stable isotope ratios ((13)C/(12)C and (15)N/(14)N) were measured in royal jelly (RJ) samples by isotope ratio mass spectrometry (IRMS) to evaluate authenticity and adulteration. Carbon and nitrogen isotope contents (given as delta values relative to a standard, delta(13)C, delta(15)N) of RJ samples from various European origins and samples from commercial sources were analyzed. Uniform delta(13)C values from -26.7 to -24.9 per thousand were observed for authentic RJ from European origins. Values of delta(15)N ranged from -1.1 to 5.8 per thousand depending on the plant sources of nectars and pollen. High delta(13)C values of several commercial RJ samples from -20.8 to -13.3 per thousand indicated adulteration with high fructose corn syrup (HFCS) as a sugar source. Use of biotechnologically produced yeast powder as protein source for the adulterated samples was assumed as delta(15)N values were lower, as described for C(4) or CAM plant sources. RJ samples from authentic and from adulterated production were distinguished. The rapid and reliable method is suitable for urgent actual requirements in food monitoring.

A measuring system for the fast simultaneous isotope ratio and elemental analysis of carbon, hydrogen, nitrogen and sulfur in food commodities and other biological material

The isotope ratio of each of the light elements preserves individual information on the origin and history of organic natural compounds. Therefore, a multi-element isotope ratio analysis is the most efficient means for the origin and authenticity assignment of food, and also for the solution of various problems in ecology, archaeology and criminology. Due to the extraordinary relative abundances of the elements hydrogen, carbon, nitrogen and sulfur in some biological material and to the need for individual sample preparations for H and S, their isotope ratio determination currently requires at least three independent procedures and approximately 1 h of work. We present here a system for the integrated elemental and isotope ratio analysis of all four elements in one sample within 20 min. The system consists of an elemental analyser coupled to an isotope ratio mass spectrometer with an inlet system for four reference gases (N(2), CO(2), H(2) and SO(2)). The combustion gases are separated by reversible adsorption and determined by a thermoconductivity detector; H(2)O is reduced to H(2). The analyser is able to combust samples with up to 100 mg of organic material, sufficient to analyse samples with even unusual elemental ratios, in one run. A comparison of the isotope ratios of samples of water, fruit juices, cheese and ethanol from wine, analysed by the four-element analyser and by classical methods and systems, respectively, yielded excellent agreements. The sensitivity of the device for the isotope ratio measurement of C and N corresponds to that of other systems. It is less by a factor of four for H and by a factor of two for S, and the error ranges are identical to those of other systems.

Isotope characteristics of vegetables and wheat from conventional and organic production

Multielement isotope ratio analysis was checked for its suitability as a means for the discrimination between agricultural products from integrated/conventional or organic production, respectively. Differences were mainly found for delta15N-values. Paprika and tomatoes from organic production in greenhouses showed delta15N-values above+7 per thousand, whereas corresponding products from conventional cultivation had delta15N-values near 0 per thousand. Lettuce, onions, cabbage and Chinese cabbage from field production had delta15N-values in the range of+5 to+6 and+5.5 to+7.5 per thousand, respectively (conventional and organic production); these overlapping differences do not permit a reliable discrimination. The same is true for wheat, showing average delta15N-values of+2.3+/-1.0 and+3.6+/-1.6 per thousand, respectively. The unexpected relative high 15N-enrichments of vegetables from integrated production are discussed as originating, at least partially, from 15N-enrichment in the soil by NH3 evaporation and denitrification.

Biosynthesis of gallic acid in Rhus typhina: discrimination between alternative pathways from natural oxygen isotope abundance

The biosynthetic pathway of gallic acid in leaves of Rhus typhina is studied by oxygen isotope ratio mass spectrometry at natural oxygen isotope abundance. The observed delta18O-values of gallic acid indicate an 18O-enrichment of the phenolic oxygen atoms of more than 30 per thousand above that of the leaf water. This enrichment implies biogenetical equivalence with oxygen atoms of carbohydrates but not with oxygen atoms introduced by monooxygenase activation of molecular oxygen. It can be concluded that all phenolic oxygen atoms of gallic acid are retained from the carbohydrate-derived precursor 5-dehydroshikimate. This supports that gallic acid is synthesized entirely or predominantly by dehydrogenation of 5-dehydroshikimate.

Sucrose metabolism and exopolysaccharide production in wheat and rye sourdoughs by Lactobacillus sanfranciscensis

The exopolysaccharide (EPS) produced from sucrose by Lactobacillus sanfranciscensis LTH2590 is predominantly composed of fructose. EPS production during sourdough fermentation has the potential to affect rheological properties of the dough as well as the volume, texture, and keepability of bread. Its in situ production by L. sanfranciscensis LTH2590 was demonstrated during sourdough fermentation after the hydrolysis of water soluble polysaccharides. In wheat and rye doughs with sucrose addition the concentration of fructose in the hydrolysate of polysaccharides was significantly higher than that in the hydrolysate of control doughs or doughs without sucrose addition. EPS production by L. sanfranciscensis in wheat doughs was confirmed by the determination of delta (13)C values of water soluble polysaccharides after the addition of naturally labeled sucrose, originating from C(3)- and C(4)-plants. In rye doughs, evidence for EPS production with the isotope technique could be demonstrated only by the determination of delta (13)C values of fructose from water soluble polysaccharides. In addition to EPS formation from sucrose, sucrose hydrolysis by L. sanfranciscensis in wheat and rye sourdoughs resulted in an increase of mannitol and acetate concentrations and in accumulation of glucose. It was furthermore observed that flour arabinoxylans were solublized during the fermentation.

18O pattern and biosynthesis of natural plant products

Oxygen atoms in plant products originate from CO(2), H(2)O and O(2), precursors with quite different delta18O values. Furthermore their incorporation by different reactions implies isotope effects. On this base the resulting non-statistical 18O distributions in natural compounds are discussed. The delta18O value of cellulose is correlated to that of the leaf water, and the observed 18O enrichment (approximately +27 per thousand) is generally attributed to an equilibrium isotope effect between carbonyl groups and water. However, as soluble and heterotrophically synthesised carbohydrates show other correlations, a non-statistical 18O distribution - originating from individual biosynthetic reactions - is postulated for carbohydrates. Similarly, the delta18O values of organic acids, carbonyl compounds, alcohols and esters indicate water-correlated, but individual 18O abundances (e.g. O from acyl groups approximately +19% above water), depending upon origin and biosyntheses. Alcoholic groups introduced by monooxygenase reactions, e.g. in sterols and phenols, show delta18O values near +5 per thousand, in agreement with an assumed isotope fractionation factor of approximately 1.02 on the reaction with atmospheric oxygen (delta18O=+23.5 per thousand). Correspondingly, a "thermodynamically ordered isotope distribution" is only observed for oxygen in some functional groups correlated to an origin from CO(2) and H(2)O, not from O(2). The individual isotopic increments of functional groups permit the prediction of global delta18O values of natural compounds on the basis of their biosynthesis.

Sealing of postoperative axillary leakage after axillary lymphadenectomy using a fibrin glue coated collagen patch: a prospective randomised study

Seroma formation after axillary lymphadenectomy in women with breast cancer remains a problem despite many efforts to reduce surgery-related morbidity. In a prospective, randomised, open, parallel-group, controlled clinical trial we evaluated the effect of a fibrin-glue coated collagen patch (TachoComb H, Nycomed Pharma AS, Denmark) on volume and duration of postoperative axillary drainage, duration of hospital stay, and procedural safety. Sixty patients were included in the study. Patients did not differ with respect to general characteristics, such as age, body mass index, treatment modality, and tumor stage distribution. In 29 patients, a fibrin-glue coated collagen patch was applied from the apex axillae to the thoracic longus nerve and half a patch was applied to the lateral border of the axillary nerve-vessel bundle. Thirty-one patients were randomised to standard closure of the axillary lymphadenectomy area. The mean duration of axillary drainage was 3.8 +/- 1.9 days in the fibrin-glue treatment group and 3.9 +/- 1.8 days in the control group (p = NS). The mean total drainage volume was 338.5 +/- 251.8 ml in the fibrin-glue treatment group and 370.8 +/- 314.6 ml in the standard closure group (p = NS). The mean length of post-operative hospital stay was 9.1 +/- 2.7 days in the fibrin-glue treatment group and 9.3 +/- 3.6 days in the standard closure group (p = NS). Seven patients (25%) and eight patients (25%) were diagnosed with local inflammation in the fibrin-glue treatment group and the standard closure group, respectively (p = NS). Seroma formation after drain removal was found in 11 patients (39%) in the fibrin-glue treatment group and in 13 patients (42%) in the standard closure group (p = NS). In summary, we observed no statistically significant differences with respect to axillary drainage time, drainage volume, length of hospital stay, local inflammation, and seroma formation after drainage removal.

Determination of the (13)C Content of Glycerol Samples of Different Origin

The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different sources has been determined. The results indicate that it is possible to distinguish the glycerol obtained from the glycerides produced in plants following C-3 and C-4 carbon fixation pathways. The samples obtained from animal sources seem to reflect the composition of the material consumed, as well as that produced by sugar fermentation.

Evidence for a nonstatistical carbon isotope distribution in natural glucose

The relative carbon isotope content (delta(13)C value) in each position of glucose from a C(4) plant (maize starch) and a C(3) plant (sugar beet sucrose) has been determined by stepwise chemical and biochemical degradation of the molecule and stable isotope ratio measurement of the fragments. The suitability of the degradation methods has been tested through their chemical yield and isotope balance. The results from both methods agreed perfectly, revealing a defined and reproducible (13)C distribution in glucose from both origins. Most prominent was a relative (13)C enrichment by 5 to 6 delta-units in position 4 and a depletion by about 5 delta-units in carbon 6. As possible reasons for these nonstatistical isotope distributions, isotope effects of the aldolase, the triose phosphate isomerase, and the transketolase reactions during carbohydrate biosynthesis are discussed. The practical importance of the results in regard to isotope distributions in secondary plant products as a means for food authenticity control is outlined.