Agricultural exposures and DNA damage in PBMC of female farmers measured using the alkaline comet assay

OBJECTIVE

Several studies investigated the link between agricultural occupational exposures and DNA damage, in an attempt to bring elements of biological plausibility to the increased cancer risk associated with them. However, only a few of these studies focused on females.

METHODS

The comet assay was performed on PBMC (Peripheral Blood Mononuclear Cells) samples from 245 females working in open field farming and cattle raising, located in the Normandy area of France. Individual questionnaires on tasks performed were administered at the time of sampling to directly assess exposures. Environmental exposures were issued from a questionnaire assessing the farm productions. Linear regression analyses were done using the DNA damage scores.

RESULTS

Regarding direct exposures, several tasks associated with exposure to potentially harmful chemicals were not associated with DNA damage, but a longer duration of use of herbicide on meadows (p = 0.05) or of cleaning and upkeep of agricultural equipment (p = 0.06) revealed higher DNA damage levels, although the number of exposed women was low. Several indirect and/or environmental exposures were associated with DNA damage in multivariate analyses: a larger surface of meadows (p = 0.006) or the presence of poultry (p = 0.03) was associated with less DNA damage, while the presence of swine (p = 0.01) was associated with higher DNA damage. Smokers and former smokers had less DNA damage than non-smokers (p = 0.0008 and p = 0.03).

CONCLUSIONS

We report modified levels of DNA damage for those environmentally exposed to meadows, poultry and pig farming, underlining the need for a better knowledge of the potential health risks experienced by females in this setting.

Pesticide exposure in greenspaces: Comparing field measurement of dermal contamination with values predicted by registration models

Since 2014, the Agricultural Operator Exposure Model (AOEM) has been the harmonised European model used for estimating non-dietary operator exposure to pesticide. It is based on studies conducted by the pesticide companies and it features 13 different crops including non-agricultural areas such as amenity grasslands. The objective of this study was to compare the dermal exposure measured during a field study conducted in a non-agricultural area with the corresponding values estimated by the model AOEM. The non-controlled field study was conducted in France in 2011 and included 24 private and public gardeners who apply glyphosate with knapsack sprayers. Dermal exposure was measured using the whole-body method and cotton gloves. Each measured value had an estimated value given by AOEM and we tested their correlation using linear regression. The model overestimated body exposure for all observations and there was no correlation between values. However, it underestimated hand exposure by 42 times and it systematically underestimated the exposure when the operators were wearing gloves, especially during the application. The model failed at being conservative regarding hand exposure and highly overestimated the protection afforded by the gloves. At a time of glyphosate renewed approval in Europe, non-controlled field studies conducted by academics are needed to improve AOEM model, especially in the non-agricultural sector. Indeed, among the 34 studies included in the model, none were conducted on a non-agricultural area and only four assessed the exposure when using a knapsack sprayer. Moreover, knapsack sprayers being the main equipment used worldwide in both agricultural and non-agricultural settings, it is also crucial to integrate new data specific to this equipment in the model. Operator exposure should be estimated with accuracy in the registration process of pesticides to ensure proper safety as well as in epidemiological studies to improve exposure assessment.

The Management of Persistent Distal Occlusions after Mechanical Thrombectomy and Thrombolysis: An Inter- and Intrarater Agreement Study

BACKGROUND AND PURPOSE

The best management of patients with persistent distal occlusion after mechanical thrombectomy with or without IV thrombolysis remains unknown. We sought to evaluate the variability and agreement in decision-making for persistent distal occlusions.

MATERIALS AND METHODS

A portfolio of 60 cases was sent to clinicians with varying backgrounds and experience. Responders were asked whether they considered conservative management or rescue therapy (stent retriever, aspiration, or intra-arterial thrombolytics) a treatment option as well as their willingness to enroll patients in a randomized trial. Agreement was assessed using κ statistics.

RESULTS

The electronic survey was answered by 31 physicians (8 vascular neurologists and 23 interventional neuroradiologists). Decisions for rescue therapies were more frequent (n = 1116/1860, 60%) than for conservative management (n = 744/1860, 40%; P < .001). Interrater agreement regarding the final management decision was "slight" (κ = 0.12; 95% CI, 0.09-0.14) and did not improve when subgroups of clinicians were studied according to background, experience, and specialty or when cases were grouped according to the level of occlusion. On delayed re-questioning, 23 of 29 respondents (79.3%) disagreed with themselves on at least 20% of cases. Respondents were willing to offer trial participation in 1295 of 1860 (69.6%) cases.

CONCLUSIONS

Individuals did not agree regarding the best management of patients with persistent distal occlusion after mechanical thrombectomy and IV thrombolysis. There is sufficient uncertainty to justify a dedicated randomized trial.

Diagnostic and therapeutic approach to adult central nervous system vasculitis

The clinical manifestations of central nervous system (CNS) vasculitis are highly variable. In the absence of a positive CNS biopsy, CNS vasculitis is particularly suspected when markers of both vascular disease and inflammation are present. To facilitate the clinical and therapeutic approach to this rare condition, CNS vasculitis can be classified according to the size of the involved vessels. Vascular imaging is used to identify medium vessel disease. Small vessel disease can only be diagnosed with a CNS biopsy. Medium vessel vasculitis usually presents with focal neurological signs, while small vessel vasculitis more often leads to cognitive deficits, altered level of consciousness and seizures. Markers of CNS inflammation include cerebrospinal fluid pleocytosis or elevated protein levels, and vessel wall, parenchymal or leptomeningeal enhancement. The broad range of differential diagnoses of CNS vasculitis can be narrowed based on the disease subtype. Common mimickers of medium vessel vasculitis include intracranial atherosclerosis and reversible cerebral vasoconstriction syndrome. The diagnostic workup aims to answer two questions: is the neurological presentation secondary to a vasculitic process, and if so, is the vasculitis primary (i.e., primary angiitis of the CNS) or secondary (e.g., to a systemic vasculitis, connective tissue disorder, infection, malignancy or drug use)? In primary angiitis of the CNS, glucocorticoids and cyclophosphamide are most often used for induction therapy, but rituximab may be an alternative. Based on the available evidence, all patients should receive maintenance immunosuppression. A multidisciplinary approach is necessary to ensure an accurate and timely diagnosis and to improve outcomes for patients with this potentially devastating condition.

Health of greenspace workers: Morbidity and mortality data from the AGRICAN cohort

INTRODUCTION

Knowledge on the health of greenspace workers is scarce, even though they are exposed to many occupational hazards. The aim of this study was to analyze mortality by cause, prevalence of some non-cancer diseases, and incidence of the main cancers among greenspace workers.

METHODS

A sub-cohort of greenspace workers was formed within the AGRICAN cohort. Demographic information, health characteristics and self-reported diseases at enrollment were described separately in terms of frequencies (%), median and Interquartile Range (IQR) for greenspace workers, farmers, and other non-agricultural workers. Causes of death and cancer incidence were identified through linkage with cancer registries from enrollment (2005-2007) to 2015. Hazard ratio (HR) and 95% Confidence Intervals [95% CI] were estimated using Cox proportional hazard regression with age as the underlying timescale.

RESULTS

The sub-cohort included 6247 greenspace workers who were higher proportion men, younger and more frequently smokers than farmers and non-agricultural workers. Male and female greenspace workers reported more history of allergic diseases; and males, more history of depression. Compared to other workers male greenspace workers showed a non-significant higher mortality from ischemic cardiological diseases (HR = 1.14 [0.81-1.60]). Incidence was higher in male greenspace workers than farmers for overall cancer (HR = 1.15 [1.04-1.27]), cancer of the prostate (HR = 1.21 [1.02-1.44]), thyroid (HR = 2.84 [1.26-6.41]), testis (HR = 3.98 [1.50-10.58]) and skin melanoma (HR = 2.15 [1.33-3.47]). Non-significant increased risks were also found for sarcomas, larynx and breast. In women, risk of breast cancer was higher in greenspace workers than in farmers (HR = 1.71 [1.17-2.50]).

CONCLUSIONS

Whereas greenspace workers have often been included with other pesticide applicators in epidemiological studies, our analyses highlighted the differences between these two populations. They demonstrate the need to study them separately and to investigate more thoroughly the role of specific occupational exposures such as pesticides as well as the effect on women.

Occupational pesticide exposure, cancer and chronic neurological disorders: A systematic review of epidemiological studies in greenspace workers

CONTEXT

The greenspace sector includes a broad range of occupations: gardeners, landscapers, municipal workers, maintenance operators of public facilities, golf-course employees and other sports facilities, horticulturists, plant and tree nursery workers etc. The health impact of occupational pesticide exposure has mainly been studied among farmers. Other professionals such as greenspace workers are also extremely exposed, presenting specific exposure features (practices, types of pesticide used). The aim of this review was to summarize epidemiological literature that examine the relationship between pesticide exposure and the risk of cancer and long-term health effects in greenspace workers.

METHOD

Six main groups of greenspace workers were identified and examined through a systematic literature review based on PubMed and Scopus. The studies were then grouped according to their design, health outcomes and the type of population studied.

RESULTS

Forty-four articles were selected among the 1679 identified. Fifteen studies were conducted exclusively among greenspace workers, while ten also studied these workers with other pesticide applicators. Six were cohorts from the general population in which greenspace workers were identified. Elevated risks were found in several studies for leukaemia, soft-tissue sarcoma, multiple myeloma, non-Hodgkin lymphoma and Parkinson's disease.

DISCUSSION

The majority of studies used rough parameters for defining exposure such as job titles which could lead to the misclassification of exposure, with the risk of false or positive negative conclusions. Health outcomes were mainly collected through registries or death certificates, and information regarding potential confounders was often missing.

CONCLUSION

The review identified only 15 studies conducted exclusively among greenspace workers. Elevated risk was found for several sites of cancer and Parkinson's diseases. Further epidemiological research is needed, conducted specifically on these workers, to better characterize this population, its exposure to pesticides and the related health effects.

Deep learning methods to generate synthetic CT from MRI in radiotherapy: A literature review

PURPOSE

In radiotherapy, MRI is used for target volume and organs-at-risk delineation for its superior soft-tissue contrast as compared to CT imaging. However, MRI does not provide the electron density of tissue necessary for dose calculation. Several methods of synthetic-CT (sCT) generation from MRI data have been developed for radiotherapy dose calculation. This work reviewed deep learning (DL) sCT generation methods and their associated image and dose evaluation, in the context of MRI-based dose calculation.

METHODS

We searched the PubMed and ScienceDirect electronic databases from January 2010 to March 2021. For each paper, several items were screened and compiled in figures and tables.

RESULTS

This review included 57 studies. The DL methods were either generator-only based (45% of the reviewed studies), or generative adversarial network (GAN) architecture and its variants (55% of the reviewed studies). The brain and pelvis were the most commonly investigated anatomical localizations (39% and 28% of the reviewed studies, respectively), and more rarely, the head-and-neck (H&N) (15%), abdomen (10%), liver (5%) or breast (3%). All the studies performed an image evaluation of sCTs with a diversity of metrics, with only 36 studies performing dosimetric evaluations of sCT.

CONCLUSIONS

The median mean absolute errors were around 76 HU for the brain and H&N sCTs and 40 HU for the pelvis sCTs. For the brain, the mean dose difference between the sCT and the reference CT was <2%. For the H&N and pelvis, the mean dose difference was below 1% in most of the studies. Recent GAN architectures have advantages compared to generator-only, but no superiority was found in term of image or dose sCT uncertainties. Key challenges of DL-based sCT generation methods from MRI in radiotherapy is the management of movement for abdominal and thoracic localizations, the standardization of sCT evaluation, and the investigation of multicenter impacts.

[Oral hairy leukoplakia induced by topical steroids]

BACKGROUND

Oral hairy leukoplakia (OHL) is an EBV-associated condition of the oral mucosa, which is often painless. It is found predominantly in HIV-positive patients and is considered a clinical indicator of immunosuppression. OHL has rarely been described in HIV-negative patients, being found most often in association with iatrogenic immunosuppression. OHL induced by topical steroids remains extremely rare.

PATIENTS AND METHODS

An 81-year-old HIV-negative woman, treated for 3 months with topical steroids for oral lichen planus, developed an asymptomatic white, corrugated, non-removable plaque with vertical folds on the lateral edge of the tongue. Associated oral candidiasis was noted. Based upon histological findings and in situ hybridisation showing numerous EBV-infected epithelial cells, a diagnosis of oral hairy leucoplakia was made.

DISCUSSION AND CONCLUSION

To our knowledge, we report herein only the second recorded case of OHL induced strictly by topical steroids. Self-medication and poor adherence to dosage recommendations were noted in the patient's medical history. Physicians must be aware of the rare but nevertheless possible adverse events associated with topical steroid use, particularly when such medication is prescribed over a long period for inflammatory diseases of the oral mucosa.

Preparation and pharmacological profile of 2-trifluoromethyl-benzo(8,9)-1,3-diaza-spiro (4,6)-undeca-2,8-diene and its enantiomers as new anti-obesity agents

Obesity affects a large population of industrialised countries in which occurrence may reach 20%. The multifactorial aspect of the pathology prompted us to develop new entities associating favourable effects on both eating behaviour and metabolic parameters. The 2-trifluoromethyl-benzocyloheptene moiety has been combined with an imidazoline ring for synthesising a new anti-obesity agent. Preparation of the already known 2-trifluoromethyl-5-H-6,7,8,9-tetrahydro-benzocyclohepten-7-one as a key intermediate has been significantly improved, and an enantioselective procedure has been developed for imidazoline construction. The syntheses and pharmacological profiles of the compounds are presented here, particularly the effects on eating behaviour and body weight, and the putative involvement of the L-enantiomer in the treatment of metabolic diseases.

Food intake regulation in rodents: Y5 or Y1 NPY receptors or both?

Neuropeptide Y (NPY), one of the most abundant peptides in rat and human brains, appears to act in the hypothalamus to stimulate feeding. It was first suggested that the NPY Y1 receptor (Y1R) was involved in feeding stimulated by NPY. More recently a novel NPY receptor subtype (Y5R) was identified in rat and human as the NPY feeding receptor subtype. There is, however, no absolute consensus since selective Y1R antagonists also antagonize NPY-induced hyperphagia. Nevertheless, new anti-obesity drugs may emerge from further pharmacological characterization of the NPY receptors and their antagonists. A large panel of Y1R and Y5R antagonists (such as CGP71683A, BIBO3304, BIBP3226, 1229U91, and SYNAPTIC and BANYU derivatives but also patentable in-house-synthesized compounds) have been evaluated through in vitro and in vivo tests in an attempt to establish a predictive relationship between the binding selectivity for human receptors, the potency in isolated organs assays, and the inhibitory effect on food intake in both normal and obese hyperphagic rodents. Although these results do not allow one to conclude on the implication of a single receptor subtype at the molecular level, this approach is crucial for the design of novel NPY receptor antagonists with potential use as anti-obesity drugs and for evaluation of their possible adverse peripheral side effects, such as hypotension.

General pharmacology of S 15261, a new concept for treatment of diabetes

The new compound S 15261 (CAS 159978-02-6) is the I-isomer of 3-[2-[2-[4-[2-(alpha-Fluorenylacetylamino)ethyl]benzoyloxy]ethylam ino]-1- methoxyethyl]trifluoromethylbenzene. The general synthetic pathway used for the preparation of S 15261 and related esters is given in this paper. This compound was selected for its promising therapeutical action on blood glucose, insulin resistance and associated risk factors present in patients with non-insulin-dependent Diabetes mellitus (NIDDM). The general pharmacological profile of S 15261 was investigated. The data given in this paper show that S 15261 has presented a very low acute toxicity (lethal dose in mice greater than 1600 mg/kg orally) and did not induce significant behavioural changes in rats. A poor anorectic effects was observed after acute administration in rats. In guinea pigs S 15261 acutely induced a significant and dose-dependent hypoglycaemic effect (ED25 = 40 mg/kg orally). Biogenic amines and their metabolites in different structures of the brain were only slightly affected after acute administration of S 15261. Chronic administration of this compound (2.5 mg/kg bid for 14 days p.o.) did not cause significant alterations in the brain amines content, with the exception of an increase of serotonin (19%) in the striatum, a result not confirmed by the dose-effect study (from 1 mg/kg to 12.5 mg/kg bid for 14 days p.o.). In vitro binding assays with 31 different receptors did not show significant affinity of S 15261 for any of them. The rat arterial blood pressure was decreased (12 mmHg) after acute (25 mg/kg i.v.) or repeated administration (2.5 mg/kg bid for 14 days p.o.) without any dose-dependent effect. We therefore conclude that S 15261 may not have significant adverse effect even at doses higher than the pharmacological effective range of doses. Although the mechanism of action of this new class of compounds was not fully understood, other pharmacological data suggest that S 15261 acts at both the liver (intraportal infusion) and skeletal muscle (microdialysis studies) at least in part to enhance insulin sensitivity. For all these activities S 15261 may be useful to treat patients with NIDDM or insulin resistance known to be the major risk for onset of NIDDM.

Detection and measurement of fetomaternal hemorrhage following diagnostic cordocentesis

OBJECTIVE

The aim of this study was to investigate the effect of cordocentesis on fetomaternal hemorrhage (FMH).

METHODS

One hundred and three diagnostic cordocenteses, without any other associated procedure, were performed at 23-40 weeks' gestation. FMH was detected using the Kleihauer-Betke staining of maternal blood taken immediately before and after cordocentesis.

RESULTS

Significant FMH occurred after 40 (38.8%) of the 103 procedures. An increased risk of fetal bleeding was associated with both an anterior placenta (odds ratio (OR) 5.89; 95% confidence interval (CI) 2.27-15.3; p < 0. 001) and a transplacental cordocentesis (OR 37.0; 95% CI 2.15-636; p < 0.001). The volume of FMH was greater after cordocentesis with an anterior placenta (90th percentile 6.20 ml) than after cordocentesis with a lateral (90th percentile 4.58 ml) or posterior placenta (90th percentile 1.35 ml) (p < 0.001). After fetal blood sampling, significant FMH occurred more frequently with a procedure duration of 3 min or more (OR 4.45; 95% CI 1.70-11.7; p = 0.002) and with two or more needle insertions (OR 4.65; 95% CI 1.80-12.1; p = 0.001).

CONCLUSION

FMH following cordocentesis may be related to placental injuries. This event is influenced by placental location, procedure duration and the number of needle insertions.

Lack of insulin resistance in the Lyon hypertensive rat

Genetically hypertensive rats (LH) of the Lyon strain, compared to their normo-tensive (LN) controls associate, in a unique manner, high blood pressure with increases in body weight and in plasma lipids and insulin/glucose ratio. The present work investigated the development of insulin resistance with age in this model. At the age of 22 and 52 weeks, LH and LN fasted male rats were submitted to an intravenous glucose tolerance test, allowing measurement of the elimination rate of the glucose and the area under the curve of the insulin response. Insulin sensitivity was calculated as the ratio of these two parameters. It was observed that insulin sensitivity coefficient decreased with age in all the animals and that LH rats did not significantly differ from LN controls (from 62.6 +/- 3.3 and 69.1 +/- 4 at 22 weeks to 42.1 +/- 4.4 and 49.5 +/- 12.8 at 52 weeks for LH and LN rats, respectively). It is concluded that 1) elevated plasma insulin/glucose ratio does not mean insulin resistance and 2) hypertension can develop without being associated, even in aged rats, to a true insulin resistance.

Aprotinin

OBJECTIVE

To review the clinical pharmacology of aprotinin in patients undergoing surgical procedures involving major blood loss, namely, coronary artery bypass graft (CABG).

DATA SOURCES

A MEDLINE search was used to identify French- and English-language publications on aprotinin using the indexing terms aprotinin, cardiothoracic surgery, and hemorrhage. The MEDLINE search was supplemented by review of article bibliographies. Data also were obtained from the approved Canadian and US product labels.

STUDY SELECTIONS

All abstracts and uncontrolled and controlled clinical trials were reviewed.

DATA EXTRACTION

Study design, population, results, and safety information were retained. Efficacy conclusions were drawn from controlled trials.

DATA SYNTHESIS

Aprotinin, a serine protease inhibitor isolated from bovine lung tissue, decreases bleeding after cardiac surgery by mechanisms including antifibrinolytic activity and preservation of platelet function. Several trials have shown that aprotinin reduced blood loss and transfusion requirements in patients undergoing CABG. Its use in other surgical procedures involving major blood loss has been reported. Aprotinin is well tolerated, with minor allergic reactions being the most frequently reported adverse effect. Although unsubstantiated, the possibility that aprotinin could create a prothrombic state leading to early graft occlusion and formation of microthrombi in renal and coronary vasculatures is of concern.

CONCLUSIONS

Aprotinin is an effective hemostatic agent in CABG. Clear definitions of indications, dosing, safety, and repeated use remain to be investigated thoroughly.

Euglycaemic and biological activities of novel thiazolidine-2,4-dione derivatives

A new series of thiazolidine-2,4-dione derivatives was obtained by incorporating one or the other of the two carbons of the central chain into different rings. These compounds lower blood glucose levels in the genetically obese and insulin-resistant ob/ob mouse. Moreover, they decreased insulin and triglyceride levels in the Zucker fa/fa rat. Incorporation of the left hand carbon of the chain afforded compounds among which pyrrolidino derivatives 5, 9 and 13 were the most potent. The same carbon atom was used to elaborate different types of rings (benzocyclobutane, benzodioxane), giving rise to compounds 14 and 19 with moderate to good activity. Finally, cyclization using the right hand carbon of the chain gave rise to highly potent benzofurane 24.

Synthesis of 1,2-diacyl-3-nicotinoyl glycerol derivatives and evaluation of their acute effects on plasma lipids in the rat

Nicotinic acid (CAS 59-67-6) is the only hypolipidemic agent whose activity has been shown both on atherosclerotic lesions and on long term mortality. Unfortunately, its use is hindered by the frequent occurrence ( > 70%) of adverse reactions (i.e. cutaneous rash, pruritus and, most significantly, flush). New prodrugs of nicotinic acid have been prepared by the use of diacylglycerol esters. In the rat, after acute oral administration of these products, a significant decrease of the free fatty acid plasma levels was obtained without the dramatic increase in nicotinic acid plasma levels observed after the oral administration of an equimolecular dose of nicotinic acid. The most interesting ester, S 16961 ((d,l)-1,2-dipalmitoyl-3-nicotinoyl glycerol, CAS 160555-46-4) is undergoing clinical trials.

Latent autoimmune diabetes mellitus in adult humans with non-insulin-dependent diabetes: is Psammomys obesus a suitable animal model?

Recent data suggest that in a proportion of NIDDM patients there is a slowly evolving insulitis which results in a latent autoimmune diabetes leading to full insulin-dependence. Many animal models exist of NIDDM but none have reported the spontaneous existence of a similar phenomenon. We have re-examined the histology of pancreata from a few Psammomys obesus who had become insulin-dependent in the late stages of NIDDM. We report here the unexpected finding of the presence of insulitis in these animals and suggest that they could be a model for the clinical observation of latent IDDM in NIDDM patients.

An empirical comparison between the DSM and psychodynamic approaches for assessment of child disorders in children attending outpatient clinics

The DSM and psychodynamic approaches provide different perspectives on child psychiatric diagnoses. Taking advantage of the recent publication of a psychodynamically oriented classification of child disorders, correspondences between these approaches were studied in a sample of outpatient clinic children. Clinician judges and a psychiatric interview schedule provided for diagnoses. Classifications of child psychopathology are still imperfect to a large extent. As a result, statistical comparisons can only yield limited relationships and caution is necessary when using classification tools. Methodological difficulties notwithstanding, various associations showed that DSM and psychodynamic constructs, while different, are not entirely independent.

S15261, a new compound for the treatment of the insulin resistance syndrome

A new oral agent, S15261 (the L-isomer of 3-[2-[2-[4-[2-[alpha-fluorenyl acetyl amino ethyl] benzoyloxy] ethyl amino] 1-methoxy ethyl] trifluoromethyl-benzene), has been developed for the treatment of the so-called "insulin resistance syndrome". In obese, insulin-resistant ageing Sprague-Dawley rats, chronic treatment with S15261 (0.5-2.5 mg.kg-1.day-1 twice per day, for 14 days) resulted in dose-dependent decreases in plasma insulin (43%), and triglyceride levels (36%), and in an increase of the glucose disposal rate during an intravenous glucose tolerance test (IVGTT) (48.5%). An increase in peripheral insulin sensitivity produced by S15261 was revealed by the glucose clamp technique. Thus, the glucose infusion rate was increased by 20% whilst steady-state insulin levels decreased by 15%. At the higher doses S15261 led to a decrease in body weight (3%), plasma glucose (13%) and blood pressure (8 mm Hg) in mildly hypertensive animals. At the doses used to achieve these results, the compound has no hypoglycaemic activity in normoglycaemic animals. Acute administration of S15261 directly into the portal vein provoked a marked increase in glucose disappearance rate during an intravenous glucose tolerance test (60%) and also in the pancreatic response to the glucose challenge. Thus, acute administration of the compound has a direct effect on glucose metabolism. These data suggest that S15261 could be a useful agent for the treatment of the insulin resistance syndrome.

Islet amyloid polypeptide in Psammomys obesus: lack of correlation between insulin resistance and plasma IAPP levels

Sand rats (Psammomys obesus) develop insulin resistance and diabetes when given a standard laboratory diet. We have examined the presence of islet amyloid polypeptide (IAPP), or amylin, in these animals. IAPP is present in the beta-cells of pancreatic islets, its localization and intensity of immuno-reactivity are, thus, similar to that of insulin. In insulin resistant Psammomys obesus, insulin and IAPP immuno-reactivity in pancreas are markedly decreased, plasma insulin levels are 20-fold higher than in controls but IAPP levels are not different from those of normal animals. Therefore, insulin resistance in Psammomys obesus does not appear to result from an elevated plasma IAPP level nor from development of amyloid deposits.

Effect of aging and drug-induced weight reduction on rat vascular reactivity

We determined the effects of D-fenfluramine treatment on the changes in vascular reactivity induced by aging. Nine- and 49-week-old Sprague-Dawley rats (a strain known to develop hyperinsulinemia and glucose intolerance during the aging process) were treated for 3 weeks either with D-fenfluramine 2.5 mg/kg twice daily orally or with vehicle. The rats were then exsanguinated and the abdominal aorta was carefully removed, cut into rings, and suspended in organ chambers for isometric tension recording. Control old rats (vehicle) had a significantly lower glucose infusion rate (an index of insulin resistance), and higher blood pressure (BP), glycemia, and insulinemia than young rats. The D-fenfluramine treatment in the aged animals produced a significant decrease in insulinemia and body weight. In aorta from the older treated and nontreated animals, the contraction to alpha-adrenergic stimulation and to the thromboxane analogue U46619 was significantly reduced as compared with that in young animals, but the response to KCl was unaffected. In contrast, in the old nontreated rats, the aorta was hyperresponsive to serotonin. D-Fenfluramine abolished this hyperreactivity. The response to beta-adrenergic stimulation and to forskolin was inhibited in the older animals but was not influenced by the treatment. Endothelium-dependent relaxations to acetylcholine were not statistically different in the various groups, but the endothelium-dependent relaxation to ADP was reduced in the control group of older animals. D-Fenfluramine treatment restored the response to ADP.

Pharmacological properties of a new antiasthmatic xanthine derivative devoid of central stimulatory activity

The bronchodilating effect and other related pharmacological properties of an 8-amino alkyl substituted xanthine (S 9795) were compared with those of reference drugs, in particular theophylline. The in vitro studies using the tracheal ring, taenia coli, rat peritoneal mastocytes and enzymic preparations demonstrated the potency of S 9795 as an antiasthmatic drug, possessing protective activity superior to that of theophylline and enprofylline. S 9797 was 100 times more active as a cAMP phosphodiesterase inhibitor than theophylline. The compound also protected against mast cell degranulation and consequent release of spasmogen due to antigen-antibody reaction or induced by Ca2+ movements. Given orally or intravenously. S 9795 had a highly selective protective effect against bronchoconstriction induced by pharmacological reagents or allergic reactions with no demonstrable effect on the central nervous or cardiovascular systems. The pharmacological effects of S 9795 were of longer duration than those of theophylline and enprofylline. These studies demonstrate the potential therapeutic value of S 9795 in the therapy of bronchospastic disorders.

NMR monitoring of intracellular sodium in dog and rabbit kidney-tubules

23Na-nuclear magnetic resonance (NMR) was used to monitor intra- and extracellular sodium in suspensions of dog cortical tubules, rabbit cortical tubules, and dog thick ascending limbs. The NMR visibility of the intracellular sodium was determined by comparing the NMR and flame photometry results and by redistributing the sodium ions between the intra- and extracellular compartments using the ionophore nystatin (influx) or sodium substitution for choline in the extracellular fluid (efflux). The intracellular sodium visibility was approximately 30% for the total sodium and 58% for the transportable sodium. Addition of sodium to sodium-depleted homogenates of dog renal cortex also showed a loss of visibility. The values of the relaxation times T1 and T2 were determined but could not be correlated with the visibility measurements. The intracellular sodium concentration in dog cortical tubules incubated in optimal biochemical conditions was estimated at 51 mM and was dependent on the extracellular sodium concentration.