The stable isotope hydrology of Sable Island, Nova Scotia, Canada with implications for evaluating the water budget of wild horses

We investigated the stable isotope hydrology of Sable Island, Nova Scotia, Canada over a five year period from September, 2017 to August, 2022. The δ2H and δ18O values of integrated monthly precipitation were weakly seasonal and ranged from -66 to -15 ‰ and from -9.7 to -1.9 ‰, respectively. Fitting these monthly precipitation data resulted in a local meteoric water line (LMWL) defined by: δ2H = 7.22 ± 0.21 · δ18O + 7.50 ± 1.22 ‰. Amount-weighted annual precipitation had δ2H and δ18O values of -36 ± 11 ‰ and -6.1 ± 1.4 ‰, respectively. Deep groundwater had more negative δ2H and δ18O values than mean annual precipitation, suggesting recharge occurs mainly in the winter, while shallow groundwater had δ2H and δ18O values more consistent with mean annual precipitation or mixing of freshwater with local seawater. Surface waters had more positive values and showed evidence of isolation from the groundwater system. The stable isotopic compositions of plant (leaf) water, on the other hand, indicate plants use groundwater as their source. Fog had δ2H and δ18O values that were significantly more positive than those of local precipitation, yet had similar 17O-excess values. δ2H values of horsehair from 4 individuals lacked seasonality, but had variations typical to those of precipitation on the island. Differences in mean δ2H values of horsehair were statistically significant and suggest variations in water use may exist between spatially disparate horse communities. Our results establish an important initial framework for ongoing isotope studies of feral horses and other wildlife on Sable Island.

Delineating origins of cheetah cubs in the illegal wildlife trade: Improvements based on the use of hair δ18O measurements

All African felids are listed as vulnerable or endangered according to the IUCN (International Union for Conservation of Nature) Red List of Threatened Species. Cheetahs (Acinonyx jubatus) in particular have declined rapidly as a result of human impacts so that development of effective strategies and tools for conservation of this highly vulnerable species, as well as African felids in general, are essential for their survival in the wild. Here we use the oxygen stable isotopic compositions of cheetah hair to determine origins of cheetah cubs destined for the illegal exotic pet trade by associating individual cubs with predicted δ18O isoscape locations. We found that cheetah cubs most likely originated in East Africa, close to the corridors responsible for this aspect of the illegal wildlife trade to the Middle East. Further refinement of these assignments using a two isotope analysis (δ18O and δ13C values) indicate that these cubs were likely sourced in Southern Ethiopia or possibly as far as Tanzania. We also demonstrate that δ18O values in tissues can provide provenance information in cases where results of δ2H analyses may be obscured by the effects of metabolic routing of nutrients during nursing, starvation, or dehydration. This study demonstrates the utility of stable isotopic tools for conservation and forensic uses for endangered mammalian species.

Organic contamination detection for isotopic analysis of water by laser spectroscopy

RATIONALE

Hydrogen and oxygen stable isotope ratios (δ² H, δ¹⁷ O, and δ¹⁸ O values) are commonly used tracers of water. These ratios can be measured by isotope ratio infrared spectroscopy (IRIS). However, IRIS approaches are prone to errors induced by organic compounds present in plant, soil, and natural water samples. A novel approach using ¹⁷ O-excess values has shown promise for flagging spectrally contaminated plant samples during IRIS analysis. A systematic assessment of this flagging system is needed to prove it useful.

METHODS

Errors induced by methanol and ethanol water mixtures on measured IRIS and isotope ratio mass spectrometry (IRMS) results were evaluated. For IRIS analyses both liquid- and vapour-mode (via direct vapour equilibration) methods are used. The δ² H, δ¹⁷ O, and δ¹⁸ O values were measured and compared with known reference values to determine the errors induced by methanol and ethanol contamination. In addition, the ¹⁷ O-excess contamination detection approach was tested. This is a post-processing detection tool for both liquid and vapour IRIS triple-isotope analyses, utilizing calculated ¹⁷ O-excess values to flag contaminated samples.

RESULTS

Organic contamination induced significant errors in IRIS results, not seen in IRMS results. Methanol caused larger errors than ethanol. Results from vapour-IRIS analyses had larger errors than those from liquid-IRIS analyses. The ¹⁷ O-excess approach identified methanol driven error in liquid- and vapour-mode IRIS samples at levels where isotope results became unacceptably erroneous. For ethanol contaminated samples, a mix of erroneous and correct flagging occurred with the ¹⁷ O-excess method. Our results indicate that methanol is the more problematic contaminant for data corruption. The ¹⁷ O-excess method was therefore useful for data quality control.

CONCLUSIONS

Organic contamination caused significant errors in IRIS stable isotope results. These errors were larger during vapour analyses than during liquid IRIS analyses, and larger for methanol than ethanol contamination. The ¹⁷ O-excess method is highly sensitive for detecting narrowband (methanol) contamination error in vapour and liquid analysis modes in IRIS.

Contribution of nitrogen sources to streams in mixed-use catchments varies seasonally in a cold temperate region

Intensive agriculture and growing human populations are important nitrogen (N) sources thought to be associated with eutrophication. However, the contribution and seasonality of N delivery to streams from human activities is poorly understood and knowledge of the role of stream communities in the assimilation of N from human activities is limited. We used N and oxygen stable isotope ratios of dissolved inorganic N (DIN) and concentrations of artificial sweeteners to identify the relative contribution of key sources of anthropogenic N (i.e., fertilizers, human, and livestock waste) to tributaries of the Red River Valley (RRV), Manitoba, Canada. Water and algae were sampled in 14 RRV tributaries during snowmelt, spring, summer, and autumn; and water was sampled at three locations in the Red River in spring, summer, and autumn. δ¹⁵N values of DIN in tributary water differed seasonally and were greatest during snowmelt. Incorporation of ammonium δ¹⁵N provided evidence for the importance of manure N to tributaries during snowmelt. Fertilizer and municipal lagoons served as principal sources of N to streams in spring and summer. Human and livestock waste sources of N were the dominant contributor to algae at greater than 90% of sites and algae δ¹⁵N was greatest at sites downstream of municipal lagoons. We also showed that the tributaries contribute human and livestock waste N to the Red River, though much of the nitrate in the river originates outside of Manitoba. Overall, our study determined that the anthropogenic sources of N to RRV streams vary seasonally, likely due to regional hydrologic conditions. Our study also showed the potential of artificial sweeteners and ammonium δ¹⁵N as tools for identifying N sources to rivers. Moreover, we demonstrate the need for the management of N sources and the protection of stream function to control downstream transfer of N from landscapes to waterbodies.

Fate of bioavailable nutrients released to a stream during episodic effluent releases from a municipal wastewater treatment lagoon

Municipal wastewater lagoons are common across North America and, unlike larger mechanical wastewater treatment plants, typically release nutrient-rich effluent directly to rivers in intermittent pulses. However, little is known about the fate of nutrients from these episodic events, which may happen under varying hydrologic or thermal conditions. We assessed fate of nitrogen (N) and phosphorus (P) from lagoon effluent during three releases to Deadhorse Creek, Manitoba, Canada. Using net nutrient uptake lengths and natural abundance stable isotope ratios of dissolved inorganic nitrogen (DIN) and primary producers, we found that DIN was processed during the summer releases though the dominant mechanism was unclear. However, nitrate was largely exported in autumn. Primary producers assimilated lagoon N but did not appear to reduce DIN concentrations. The longitudinal pattern of soluble reactive phosphorus (SRP) varied between releases and in summer 2019 the stream became a net source of SRP despite concomitant processing of DIN. We hypothesize that low demand for P in Deadhorse Creek, as suggested by upstream SRP > 0.05 mg P L-1, and nutrient ratios indicative of N limitation, reduced instream processing of P. Furthermore, our results indicated that cool or high flow conditions may result in the export of much of the lagoon nutrient load downstream. Our findings suggest the processes that transform wastewater nutrients are overwhelmed during effluent releases. Managers should consider increasing effluent dilution via continuous release of effluent rather than pulsed delivery. However, management of upstream nutrient supply may also be needed when relying upon the self-purifying capacity of rivers.

Tracking cats revisited: Placing terrestrial mammalian carnivores on δ2H and δ18O isoscapes

The relationship between hydrogen and oxygen stable isotopic compositions in environmental water and hair was investigated for both domestic cats (Felis catus) and dogs (Canis lupus familiaris). A strong, but different, covariance was measured between the hydrogen and oxygen stable isotopic compositions of local precipitation and hair keratin from both cats and dogs. These isotopic differences are most likely a result of the differences between the dietary and drinking water needs of cats compared to dogs. Moreover, the δ²H and δ¹⁸O values of hair from captive and wild felids and canids, such as cougars (Puma concolor), bobcats (Lynx rufus), and wolves (Canis lupus) are broadly consistent with these measurements. This evidence indicates that while the water budgets of terrestrial mammalian carnivores need to be considered in isotopic applications, it is clear that felids and canids may be placed on tissue–specific hydrogen and oxygen isotopic landscapes for ecological, provenance, or forensic studies.

Snow gauge undercatch and its effect on the hydrogen and oxygen stable isotopic composition of precipitation

We investigated the influence of post-collection changes and snow gauge undercatch on the stable isotopic compositions of winter precipitation. Post-collection changes by evaporation or sublimation can be severe, and may be minimized, but not eliminated, by emptying collection gauges immediately after snowfall. Snow gauge undercatch caused two main effects: a small direct effect caused by preferential separation of snow particles during snowfall, and a much larger effect on the measured stable isotopic compositions of average annual precipitation as a result of under representation of winter precipitation. Despite these effects, however, we found little change to calculated local meteoric water lines (LMWL) for Saskatoon, SK, Canada. A comprehensive 27-year LMWL for Saskatoon which incorporates these effects can be described by δ²H = 7.69 ± 0.096 × δ¹⁸O - 2.22 ± 1.72 (r² = 0.97, n = 208).

Impact of physical exercise on sensor performance of the FreeStyle Libre intermittently viewed continuous glucose monitoring system in people with Type 1 diabetes: a randomized crossover trial

AIMS

To evaluate the sensor performance of the FreeStyle Libre intermittently viewed continuous glucose monitoring system using reference blood glucose levels during moderate-intensity exercise while on either full or reduced basal insulin dose in people with Type 1 diabetes.

METHODS

Ten participants with Type 1 diabetes [four women, mean ± sd age 31.4 ± 9.0 years, BMI 25.5±3.8 kg/m² , HbA_1c 55±7 mmol/mol (7.2±0.6%)] exercised on a cycle ergometer for 55 min at a moderate intensity for 5 consecutive days at the clinical research facility, while receiving either their usual or a 75% basal insulin dose. After a 4-week washout period, participants performed the second exercise period having switched to the alternative basal insulin dose. During exercise, reference capillary blood glucose values were analysed using the fully enzymatic-amperometric method and compared with the interstitial glucose values obtained. Intermittently viewed continuous glucose monitoring accuracy was analysed according to median (interquartile range) absolute relative difference, and Clarke error grid and Bland-Altman analysis for overall glucose levels during exercise, stratified by glycaemic range and basal insulin dosing scheme (P<0.05).

RESULTS

A total of 845 glucose values were available during exercise to evaluate intermittently viewed continuous glucose monitoring sensor performance. The median (interquartile range) absolute relative difference between the reference values and those obtained by the sensor across the glycaemic range overall was 22 (13.9-29.7)%, and was 36.3 (24.2-45.2)% during hypoglycaemia, 22.8 (14.6-30.6)% during euglycaemia and 15.4 (9-21)% during hyperglycaemia. Usual basal insulin dose was associated with a worse sensor performance during exercise compared with the reduced (75%) basal insulin dose [median (interquartile range) absolute relative difference: 23.7 (17.2-30.7)% vs 20.5 (12-28.1)%; P<0.001).

CONCLUSIONS

The intermittently viewed continuous glucose monitoring sensor showed diminished accuracy during exercise. Absolute glucose readings derived from the sensor should be used cautiously and need confirmation by additional finger-prick blood glucose measurements.

Spatio-temporal variation of nitrate sources to Lake Winnipeg using N and O isotope (δ15N, δ18O) analyses

Anthropogenic nitrogen inputs into Lake Winnipeg, Canada, from watershed sources have increased during the last decades, contributing to eutrophication. These nutrient N inputs include loadings from agriculture (inorganic fertilizer and animal waste) and urban sources (wastewater discharge from sewage treatment plants). The aim of this study was to evaluate the sources and seasonal patterns of dissolved nitrates in two major contributors to Lake Winnipeg; the Assiniboine and Red rivers. The relative contribution of nitrate sources was estimated using Bayesian isotope mixing models incorporating δ¹⁵N and δ¹⁸O values of dissolved nitrate. Overall, δ¹⁵N values of nitrate in the rivers ranged from -2 ‰ to +20 ‰, and δ¹⁸O values ranged from -20 ‰ to +20 ‰, which indicated variable contribution of nitrate sources, depending on the river reach and seasonal period of sampling. The results indicated that nitrate in the Assiniboine River originated up to 62 % from waste or municipal sources (i.e. manure and/or waste water discharge), whereas ca. 40 % of nitrate in the Red River originated predominantly from inorganic agricultural fertilizers. These different source contributions were temporally variable, with a decrease in fertilizer loading following spring snowmelt. We found higher proportions of inorganic fertilizers in the Assiniboine River watershed during flooding, which has relevant implications for water nutrient management in response to stochastic flooding events.

Re-evaluation of the hydrogen stable isotopic composition of keratin calibration standards for wildlife and forensic science applications

RATIONALE

Determination of non-exchangeable hydrogen isotopic compositions (δ² H values) of bulk complex organic materials is difficult due to uncontrolled H isotope exchange between the organic material and ambient water vapor. A number of calibration keratinous materials with carefully measured hydrogen isotopic compositions of the non-exchangeable fraction were proposed to enable stable isotope laboratories to normalize their ² H measurements. However, it was recently reported that high-temperature carbon-reactor methods for measuring the hydrogen isotopic composition of nitrogenous organic materials is biased by the production of HCN in the reactor. As a result, the reported values of these calibration materials needed to be re-evaluated.

METHODS

We evaluated the non-exchangeable δ² H_VSMOW values of keratins EC1 (CBS) and EC2 (KHS), USGS hair standards, and a range of other nitrogenous widely used organic laboratory calibration materials (collagen and chitin) using pre-treatment with a preparation device designed to eliminate residual moisture and quantify exchangeable H.

RESULTS

The revised non-exchangeable δ² H_VSMOW values of EC-1 (CBS) and EC-2 (KHS) keratin standard materials were -157.0 ± 0.9 and -35.3 ± 1.1 ‰, respectively. The revised values of USGS42 and USGS43 were -72.2 ± 0.9 and -44.2 ± 1.0 ‰, respectively, in excellent agreement with previous results.

CONCLUSIONS

For routine H isotope analyses, with proper sample pre-treatment, we show that the Comparative Equilibration approach can provide accurate and reproducible non-exchangeable δ² H values among laboratories regardless of the reactor type used. © 2017 Her Majesty the Queen in Right of Canada Rapid Communications in Mass Spectrometry © 2017 John Wiley & Sons Ltd. Reproduced with the permission of the Environment and Climate Change Canada.

On the use of stable oxygen isotope (δ (18)O) measurements for tracking avian movements in North America

Tracking migratory animals has benefitted using measurements of naturally occurring stable isotopes of hydrogen (δ (2)H) in keratinous tissues such as hair and feathers to link animal origins to continental patterns or isoscapes of δ (2)H in precipitation. However, for most taxa, much less information exists on the use of stable oxygen isotope ratios (δ (18)O) despite the fact that δ (2)H and δ (18)O are strongly linked in environmental waters through the meteoric relationship and the possibility of using both isotopes to infer greater information on origins and climatic conditions where tissues are grown. A fundamental requirement of using stable isotopes to assign individuals and populations to origins is the development of a rescaling function linking environmental food web signals to the tissue of interest and for birds, this has not been carried out. Here, we derived the relationship between H and O isotopes in known source feathers of 104 individuals representing 11 species of insectivorous passerines sampled across the strong precipitation isoscape of North America. We determined again a strong expected relationship between feather δ (2)H (δ (2)Hf) and long-term amount-weighted precipitation δ (2)H (δ (2)Hp; r (2) = 0.77), but the corresponding relationship between δ (18)Of and δ (18)Op was poor (r (2) = 0.32) for the same samples. This suggests that δ (2)H measurements are currently more useful for assignment of insectivorous songbirds to precipitation isoscapes but does not preclude other uses of the δ (18)Of data. Currently, mechanisms responsible for the decoupling of H and O isotopes in food webs is poorly known, and we advocate a much broader sampling of both isotopes in the same keratinous tissues across precipitation isotope gradients and across taxa to resolve this issue and to increase the power of using water isotopes to track migratory animals.

Pharmacodynamics of the long-acting insulin analogues detemir and glargine following single-doses and under steady-state conditions in patients with type 1 diabetes

AIM

The pharmacodynamic characteristics of the basal insulin analogues insulin detemir (IDet) and insulin glargine (IGlar) have been examined extensively via euglycaemic clamp studies. However, differences in clamp methodology and in the analysis of clamp data between trials have led to confusion over the duration of action of these two insulins. The aim of this study was to address these ambiguities in the literature by assessing the pharmacodynamic properties of IDet and IGlar over 30 h under single-dose and steady-state conditions using the definitions and procedures previously standardized by Heise and Pieber in 2007.

METHODS

This was a single-centre, randomized, double-blind, glucose clamp trial involving 36 patients with type 1 diabetes.

RESULTS

The mean duration of action of IDet was 25.9 h, compared with 19.8 h for IGlar after a single-dose (NS), and 23.3 h (IDet) versus 27.1 h (IGlar) at steady-state (p < 0.0001). IDet had a significantly higher area under the curve glucose infusion rate (AUCGIR ) than IGlar over 0-12 h after a single-dose (p = 0.0018). The steady-state AUCGIR for IDet was numerically higher than IGlar over 0-12 h (728 vs. 592 mg/kg, respectively; p = NS), but significantly lower than IGlar at 12-30 h (p = 0.0003).

CONCLUSIONS

The duration of action of IDet is 23 h (range: 4.0-30.0), while that of IGlar is 27 h (range: 10.5-29.0) (95% CI: -8.1, 0.6). This suggests both insulins can be used for once-daily dosing, but individual needs must be considered.

A direct comparison of the pharmacodynamic properties of insulin detemir and neutral protamine lispro insulin in patients with type 1 diabetes

AIMS

To compare the pharmacodynamic properties of insulin detemir (detemir) and neutral protamine lispro (NPL) insulin using a euglycaemic glucose clamp.

METHODS

In a double-blind, crossover study, 30 patients with C-peptide negative type 1 diabetes were randomly assigned to a single dose (0.4 U/kg) of detemir and NPL. Plasma glucose (PG) was normalized with a variable insulin infusion and then decreased stepwise, followed by a euglycaemic clamp at 5.5 mmol/l over 32 h. Duration of action was defined as time from dosing until PG exceeded 8.3 mmol/l for at least 30 min.

RESULTS

Duration of action was similar for detemir [23.0 (range 2.25-32) h] and NPL [22.0 (9.5-32) h], p = 0.55. Using glucose infusion rate (GIR) parameters, detemir showed a flatter pharmacodynamic profile versus NPL: area under the curve, AUC(GIR) ((0-32))  = 1326 vs. 1841 mg/kg, p < 0.01 (detemir vs. NPL, respectively); AUC(GIR) ((0-12))  = 784 vs. 1392 mg/kg, p < 0.05; AUC(GIR) ((12-32))  = 455 vs. 274 mg/kg, p = 0.051; GIR(late) (12-32)/GIR(early) (0-12) ratio = 0.33 vs. 0.04, p < 0.001. Detemir also showed a lower and later peak of action than NPL [GIR(max) 2.0 vs. 3.2 mg/kg/min, p < 0.01; T(max) 9.1 (95% confidence interval: 3.0-14.7) vs. 7.0 h (1.8-15.2)].

CONCLUSIONS

Detemir and NPL had similar duration of action of approximately 24 h in patients with type 1 diabetes. Compared with NPL, detemir had a flatter profile with a more even distribution of metabolic effect over 24 h.

Measurement of stable isotope activities in saline aqueous solutions using optical spectroscopy methods

The requirement to measure the stable isotopic compositions of saline pore fluids by optical methods has prompted a re-evaluation of the isotopic salt effect for common salts. Hydrogen and oxygen isotopic salt effects were measured at room temperature (21°C) by optical methods. For hydrogen isotopes, our results agree well with those of previous studies and better define these effects at low temperatures. In contrast, measured oxygen isotope salt effects disagree within error for NaCl and CaCl2 solutions from those reported previously. Subtle differences between measurement methods may account for the discrepancy. In studies that involve highly saline fluids, the isotopic salt effect must be taken into account because modern methods that measure stable isotopic compositions as activities or concentrations may be not directly comparable to historical data sets.

An On-Line Technique for the Determination of the δ(18)O and δ(17)O of Gaseous and Dissolved Oxygen

Few studies have used the stable isotopic composition of O(2) as a tracer of gas transport or biogeochemical processes in environmental research. Here we demonstrate field sampling techniques for gaseous and dissolved O(2) and describe an analytical method for measuring δ(18)O and δ(17)O values of O(2) in air, soil gas, and water samples using continuous-flow isotope-ratio mass spectrometry (CF-IRMS). A Micromass CF-IRMS was altered to accommodate a sample gas injection port prior to a CO(2) and H(2)O trap and GC column. The GC column was a 1-m, 5-Å molecular sieve column held at 35 °C. The resolved sample O(2) was introduced to the IRMS via an open split. δ(18)O and δ(17)O values were determined by measurement of O(2) isotopes at m/z 34/32 and 33/32 and comparison to a reference pulse of O(2). Repeated injections of atmospheric oxygen yielded a repeatability (±SD) of ±0.17‰ for δ(18)O and ±0.5‰ for δ(17)O. IRMS source linearity was excellent for O(2) over a sample size range of 60-400 μL. The smallest sample for routine δ(18)O and δ(17)O determinations was ∼80 μL of O(2), with a sample analysis time of 180 s. Preliminary results from a riverine and soil gas study illustrate natural oxygen isotope fractionation processes.

Realtime stable isotope monitoring of natural waters by parallel-flow laser spectroscopy

A parallel-flow H(2)O(liquid)-H(2)O(vapor) equilibration and laser spectroscopy method provides a new way to monitor the hydrogen and oxygen stable isotopic composition of water from rivers or lakes or in hydrologic tracer tests in real time. Two custom-built equilibrator devices and one commercial membrane device were tested to determine if they could be used to convert natural water samples (lakes, rivers, groundwater) to a H(2)O gas phase for continuous online δ(18)O and δD isotopic analysis by laser spectroscopy. Both the commercial minimodule device and the marble-filled equilibrator produced water vapor in isotopic equilibrium with the flowing liquid water, suggesting that unattended field measurement using these devices is possible. Oxygen isotope disequilibrium was indicated using the minimodule device at low temperatures.

Toxicity of adjuvant sequential chemo- and radiotherapy of high-risk endometrial carcinoma (HREC)—Results of a phase II multicenter feasibility NOGGO study

16074

Background: Isolated adjuvant radio- or chemotherapy (CHT) only reduces local or distant relapses in HREC without impact on overall-survival. Therefore a multicenter feasibility study on adjuvant sequential chemo- and radiotherapy of HREC was initiated in order to evaluate safety and toxicity. Planned number of patients was 40, if after 17 pts. no termination of therapy because of toxicity was necessary, study can be closed and a phase III-study can be initiated. The data on toxicity are presented. Methods: Eligibility criteria: adenocarcinomas G1/G2 stage IC or G3 stage IA-IC or all stages II and IIIA (histological), all tumours with more than 2 cm diameter in size or non endometrioid cancers stage IA-C, II and IIIA and all cases with vessel invasion. Surgery: abdominal hysterectomy with bilateral adnexectomy without lymphadenectomy or with pelvic and para-aortic lymphadenectomy and positive lymph nodes. Further: Karnofsky-Index > 70, normal bone marrow, kidney, and liver function with laboratory tests not higher than 1.5 times of the normal local reference values. CHT: 175 mg/m2 paclitaxel plus carboplatin AUC 5, q 3 weeks for 4 cycles beginning latest 6 weeks after surgery. Within 6 further weeks after CHT an external beam irradiation (total dose 50.4 Gy, 28 fractions with 1.8 GY/d) plus 3 intracavitary HDR-iridium-192- brachytherapy courses with 3 x 5 GY were performed. Results: To date 17 pts (mean 64.1 years) completed 68 cycles CHT and following radiotherapy. There was no termination of therapy. Grade III leucopenia was observed in 9 % with 2 pts. requiring prolongation of treatment interval. There were 3 and 1 % grade II anemia and thrombocytopenia respectively. Further grade II toxicity: alopecia 38, fatigue 12, nausea/emesis 3, sensory neuropathy 12 %. Administration of G-CSF (pegfilgrastim) and epoitin (darbepoetin) was necessary in 2 and 6 % of cycles. Conclusions: Adjuvant sequential chemo- and radiotherapy of HREC is feasible by safety and toxicity and a phase III study can be initiated.

No significant financial relationships to disclose.

Fibre-related nitric oxide synthase (NOS) in Duchenne muscular dystrophy

Nitric oxide (NO) mediates fundamental physiological actions on skeletal muscle. The loss of NO synthase (NOS) from the sarcolemma was assumed to be associated with development of Duchenne muscular dystrophy (DMD). We have, however, recently reported that, in contrast to the commonly accepted view, NOS expression in DMD myofibres is up-regulated. This poses the question of the fibre type-specific NOS expression in DMD muscles and how the NOS expression is related to the regeneration or degeneration status. To address this issue, we examined localization of NOS isoforms I, II and III in skeletal muscles of DMD patients employing immunohistochemical labelling with tyramide signal amplification complemented with enzyme histochemistry. We found that NOS immunolabelling as well as metabolic enzyme activity in DMD muscles were heterogeneously distributed along the fibre length of DMD muscle fibres revealing regenerating and degenerate (hypercontracted) fibres as well as normal segments. Like in normal muscles, positive NOS immunoreactivity was found to be associated with fast-oxidative glycolytic (FOG) phenotype. The regeneration status of NOS-positive segments was deduced from the presence of neonatal and developmental myosin heavy chains. High NOS expression in regenerating DMD muscle fibres can be well reconciled with reports about the protective role of endogenous NO in inflammatory diseases and in muscle repair.

On-Line Technique for the Determination of the δ37Cl of Inorganic and Total Organic Cl in Environmental Samples

Here we describe an on-line method for measuring delta(37)Cl values of chloride bearing salts, waters, and organic materials using multicollector continuous-flow isotope ratio mass spectrometry (CF-IRMS). Pure AgCl quantitatively derived from total Cl in water, inorganic Cl salts, and biological samples was reacted with iodomethane in evacuated 10-mL stopper sealed glass vials to produce methyl chloride gas. A GV Instruments Multicollector CF-IRMS with CH(3)Cl optimized collector geometry was modified to accommodate a headspace single-sample gas injection port prior to a GC column. The GC column was a 2-m Porapak-Q packed column held at 160 degrees C. The resolved sample CH(3)Cl was introduced to the IRMS source in a helium stream via an open split. delta(37)Cl values were calculated by measurement of CH(3)Cl at m/z 52/50 and by comparison to a reference pulse of CH(3)Cl calibrated to standard mean ocean chloride. Sample CH(3)Cl analysis time was approximately 6 min. Injections of 40 microL of pure CH(3)Cl gas yielded a repeatability (+/-SD) of +/-0.06 per thousand for delta(37)Cl (n = 10). Combined GC and IRMS source linearity for CH(3)Cl was <0.2 per thousand/nA (V) peak height. External repeatability, based on processing of seawater and NaCl reference solutions, was better than +/-0.08 per thousand. The smallest sample for delta(37)Cl analysis by this method was approximately 0.2 micromol of Cl. Selected results from a river basin and biological samples study illustrate the potential of on-line chlorine isotope assays in environmental pollution studies.

High level of beta-hCG simulating pregnancy in recurrent osteosarcoma: case report and review of literature

PURPOSE

A high serum level of beta human chorionic gonadotropin (hCG) normally indicates pregnancy in healthy women. We were confused by this finding in one of our patients. This 18-year-old girl presented with amenorrhoea of 1-month duration, a positive pregnancy test and a high beta-hCG serum level although taking contraceptives. Pregnancy was excluded by ultrasound. Three years previously, she had had an osteosarcoma of the humerus. The tumour initially had been wide resected and had shown a good response to neoadjuvant chemotherapy with COSS-96-protocol.

METHODS

We reviewed the original histological result and the literature about possible similar findings. We analysed therapeutic options and the value of beta-hCG levels as a therapy monitor.

RESULTS

During examination we detected a recurrent osteosarcoma of the left humerus. The local relapse evidently expressed beta-hCG which, retrospectively, could only sparsely be shown in the primary resectate. After intralesional surgery, chemotherapy and radiotherapy levels of beta-hCG normalised.

CONCLUSION

Osteosarcoma very rarely is able to produce a paraneoplastic syndrome by high levels of beta-hCG. This may well be of diagnostic value and offer an additional monitoring tool. It can indicate tumour recurrence and dedifferentiation.

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors

PURPOSE

To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors.

MATERIALS AND METHODS

After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard.

RESULTS

Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging.

CONCLUSION

18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

The effects of critical incident stress debriefing (CISD) on emergency medical services personnel following the Los Angeles Civil Disturbance

This study examined the effects of Critical Incident Stress Debriefing (CISD) upon technicians who provided emergency medical services in South Central Los Angeles during the 1992 Los Angeles Civil Disturbance. The relationships between exposure, debriefing and symptoms of stress were identified and examined. The Frederick Reaction Index-Adult (FRI-A) was used to measure the presence of symptoms characteristic of posttraumatic stress disorder. EMTs who had the opportunity to participate in Critical Incident Stress Debriefings (n = 42) following the incident reported fewer symptoms and scored significantly lower on the FRI-A than those not participating in Critical Incident Stress Debriefing (n = 23).

Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

An automated technique for measuring deltaD and delta18O values of porewater by direct CO2 and H2 equilibration

The stable-oxygen and -hydrogen isotopic values (deltaD, delta18O) of porewater in geologic media are commonly determined on water obtained by extraction techniques such as centrifugation, mechanical squeezing, vacuum heating and cryogenic microdistillation, and azeotropic distillation. Each of these techniques may cause isotopic fractionation as part the extraction process and each is laborious. Here we demonstrate a new approach to obtain automated, high-precision deltaD and delta18O measurements of porewater in geologic sediments by direct H2- and CO2-porewater equilibration using a modified commercial CO2-water equilibrator. This technique provides an important and cost-effective improvement over current extraction methods, because many samples can be rapidly analyzed with minimal handling, thereby reducing errors and potential for isotopic fractionation. The precision and accuracy of direct H2- and CO2-porewater equilibration is comparable to or better than current porewater extraction methods. Finally, the direct equilibration technique allows investigators to obtain high-resolution (cm scale) porewater deltaD and delta18O profiles using cores from individual boreholes, eliminating the need for costly piezometers or conventional porewater extractions.

Guidelines for the development of comparative pathology

The purpose of comparative pathology is to develop a fuller understanding of pathologic processes in individuals of various species. Historically, we distinguish between direct and indirect findings. Direct sources are paleopathologic fossils. Indirect findings are historic and/or religious descriptions of epidemics. The philosophy behind the comparative approach depends primarily on the individuals of the species as units. The individual represents a concrete reality, whereas the other taxonomic categories are only theoretical entities contrived by human thought. Intraspecies-specific comparison and the interspecies-specific comparison are distinguishable. In intraspecies-specific comparison different individuals (races, breeds) of one species are compared, whereas in the interspecies-specific comparison individuals of several species are compared. Evolution and the comparative ontogenetic development of recent organisms explains how the variability of species came into existence. Consistency in evolution and uniformity is given by the fact that members of all phyla are still represented by some remaining species. Heterogeneity of organismic structures are more numerous but secondary. With the exception of the virus, the cell is remaining the unit of living matter, but viruses depend on cells for their existence. The majority of species, the eumetazoans and vascular plants, are built of true tissues developed by cell division, whereas higher fungi and some algae exhibit plectenchymata which develop by the fusion of cells. This short article presents some thoughts and principles underlining the importance of development of guideline for the study of comparative pathology.

Interleukin-6 is required in vivo for the regulation of stem cells and committed progenitors of the hematopoietic system

The development of blood cells from hematopoietic stem cells is controlled by multiple cytokines. These growth factors influence survival, cell cycle status, differentiation into lineage-committed progenitors, final maturation into blood cells, and perhaps self-renewal of stem cells. The specific contribution of IL-6 to these processes in vivo was evaluated in mice with a targeted disruption of the IL-6 gene. Decreases in the absolute numbers of CFU-Sd12 and preCFU-S, as well as in the functionality of LTRSC in these mutant mice, suggests a role for IL-6 in the survival, self-renewal, or both of hematopoietic stem cells and early progenitors. In addition, as a result of the IL-6 deficiency, the control between proliferation and differentiation of the progenitor cells of the granulocytic-monocytic, megakaryocytic, and erythroid lineages into mature blood cells is altered, leading to abnormal levels of committed progenitors of these lineages and to a slow recovery from hematopoietic ablation.

The role of interleukin-6 in mucosal IgA antibody responses in vivo

In mice with targeted disruption of the gene that encodes interleukin-6 (IL-6), greatly reduced numbers of immunoglobulin A (IgA)-producing cells were observed at mucosae and grossly deficient local antibody responses were recorded after mucosal challenge with either ovalbumin or vaccinia virus. The IgA response in the lungs was completely restored after intranasal infection with recombinant vaccinia viruses engineered to express IL-6. These findings demonstrate a critical role for IL-6 in vivo in the development of local IgA antibody responses and illustrate the effectiveness of vector-directed cytokine gene therapy.

Resistance of mice deficient in IL-4 to retrovirus-induced immunodeficiency syndrome (MAIDS)

The murine acquired immunodeficiency syndrome (MAIDS) is induced by a defective murine leukemia virus and has many symptoms similar to those found in patients infected with the human immunodeficiency virus. The presence of both B cells and CD4+ T cells is critical for the development of the disease. Furthermore, a Th2 cytokine response dominates during the progression of the disease. When interleukin-4 (IL-4)-deficient mice that are defective in Th2 cytokine responses were infected, there was no lethality, and the development of the T cell abnormalities associated with MAIDS was delayed. These data suggest that IL-4 or a Th2 response is involved in the development of retrovirus-induced immunodeficiency in mice.

Pharmacokinetics of diflunisal in patients

There are few pharmacokinetic data available on the disposition of diflunisal in patients; this study, therefore, looked at the oral absorption, distribution and elimination of this drug. Ten pharmacokinetic profiles obtained from 8 patients showed a maximum plasma diflunisal concentration of 62.0 +/- 26.5 mg/L after 2.76 +/- 1.87 hours, and an area under the plasma concentration-time curve (AUC) of 678.3 +/- 362.3 mg/L.h. Significant intra- and intersubject variability was observed in this group of patients. Analysis of biliary secretion of diflunisal in 4 patients suggested a biliary elimination and subsequent enterohepatic circulation ranging between 2.4 and 15.1%. The AUC for diflunisal in synovial fluid collected from 66 patients was about 70% of that for plasma. In none of 28 patients studied could any trace of diflunisal be observed in cerebrospinal fluid, even though the sensitivity of the assay allowed detection of concentrations as low as 0.01 mg/L.

FOOD INSPECTION AND FOOD IN RELATION TO PUBLIC HEALTH

“Why should not cities solve their milk problems as they have those of water supply?” queries Dr. Koehler. From the vital statistics of a metropolis he asserts relations between food inspection and typhoid and between pasteurization and infant mortality. He considers accurate information on dietetics a necessary health measure.