A model study of convergent dynamics in the marginal ice zone

With the increasing resolution of operational forecasting models, the marginal ice zone (MIZ), the area where waves and sea ice interact, can now be better represented. However, the proper mechanics of wave propagation and attenuation in ice, and especially their influence on sea ice dynamics, still remain poorly understood and constrained in models. Observations have shown exponential wave energy decrease with distance in sea ice, particularly strong at higher frequencies. Some of this energy is transferred to the ice, breaking it into smaller floes and weakening it, as well as exerting a stress on the ice similar to winds and currents. In this article, we present a one-dimensional, fully integrated wave and ice model that has been developed to test different parameterizations of wave-ice interactions. The response of the ice cover to the wind and wave radiative stresses is investigated for a variety of wind, wave and ice conditions at different scales. Results of sensitivity analyses reveal the complex interplay between wave attenuation and rheological parameters and suggest that the compressive strength of the MIZ may be better represented by a Mohr-Coulomb parameterization with a nonlinear dependence on thickness. This article is part of the theme issue 'Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks'.

Marginal ice zone dynamics: history, definitions and research perspectives

Despite enormous scientific and technological progress in numerical weather and climate prediction, sea ice still remains unreliably predicted by models, both in short-term forecasting and climate projection applications. The total ice extent in both hemispheres is tied to the location of the ice edge, and consequently to what happens in the portion of the ice cover immediately adjacent to the open ocean that is called the marginal ice zone (MIZ). There is mounting evidence that processes occurring in the MIZ might play an important role in the polar climate of both hemispheres, yet some key physical processes are still missing in models. As sea ice models developed for climate studies are increasingly used for operational forecasting, the missing physics also impede short-term sea ice prediction skills. This paper is a mini-review that provides a historical perspective on how MIZ research has progressed since the 1970s, with a focus on the fundamental importance of the interactions between sea ice and surface gravity waves on sea ice dynamics. Completeness is not achieved, as the body of literature is huge, scattered and rapidly growing, but the intention is to inform future collaborative research efforts to improve our understanding and predictive capabilities of sea ice dynamics in the MIZ. This article is part of the theme issue 'Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks'.

Sea-air transfer of a tracer dye observed during the Tracer Release Experiment with implications for airborne contaminant exposure

Rhodamine water tracer (RWT) released during the 2021 Tracer Release Experiment in the St. Lawrence Estuary provides a proxy for the water-soluble fractions of contaminant spills. Measurements of total and size-resolved aerosols were taken onboard a research vessel throughout the experiment. Size-resolved aerosol measurements show airborne transmission of water-soluble RWT in a bimodal distribution peaking at 5.2 μm and 0.9 μm. Highest aerosol RWT (30.5 pg m^-3) was observed in the 12-hour daytime period following the first dye release (Sept. 5), while the lowest (8.8 pg m^-3) was observed in the subsequent nighttime sample. Available wind and RWT patch information were used to identify factors contributing to the factor-of-three variation in aerosol RWT concentrations. Negligible correlations were found between aerosol RWT and wind speed and sample time-of-day. Wind direction is isolated as the key variable for consideration in identifying the impact of contaminant spills on coastal and inland communities.

Toward Food Sovereignty for Coastal Communities of Eastern Québec: Co-designing A Website to Support Consumption of Edible Resources from the St. Lawrence River, Estuary, and Gulf

Background. Despite the abundance and proximity of edible marine resources, coastal communities along the St. Lawrence in Eastern Québec rarely consume these resources. Within a community-based food sovereignty project, Manger notre Saint-Laurent (“Sustenance from our St. Lawrence”), members of participating communities (3 non-Indigenous, 1 Indigenous) identified a need for a web-based decision tool to help make informed consumption choices. Methods. We thus aimed to co-design a prototype website that facilitates informed choices about consuming local edible marine resources based on seasonal and regional availability, food safety, nutrition, and sustainability, with community members, regional stakeholders, and experts in user experience design and web development. We conducted 48 interviews with a variety of people over 3 iterative cycles, assessing the prototype’s ease of use with a validated measure, the System Usability Scale. Results. Community members, regional stakeholders, and other experts identified problematic elements in initial versions of the website (e.g., confusing symbols). We resolved issues and added features people identified as useful. Usability scores reached “best imaginable” for both the second and the third versions and did not differ significantly between sociodemographic groups. The final prototype includes a tool to explore each species and index cards to regroup accurate evidence relevant to each species. Conclusions. Engaging co-designers with different sociodemographic characteristics brought together a variety of perspectives. Several components would not have been included without co-designers’ input; other components were greatly improved thanks to their feedback. Co-design approaches in research and intervention development are preferable to foster the inclusion of a variety of people. Once the prototype is programmed and available online, we hope to evaluate the website to determine its effects on food choices.

Shells of the bivalve Astarte moerchi give new evidence of a strong pelagic-benthic coupling shift occurring since the late 1970s in the North Water polynya

Climate changes in the Arctic may weaken the currently tight pelagic-benthic coupling. In response to decreasing sea ice cover, arctic marine systems are expected to shift from a 'sea-ice algae-benthos' to a 'phytoplankton-zooplankton' dominance. We used mollusc shells as bioarchives and fatty acid trophic markers to estimate the effects of the reduction of sea ice cover on the food exported to the seafloor. Bathyal bivalve Astarte moerchi living at 600 m depth in northern Baffin Bay reveals a clear shift in growth variations and Ba/Ca ratios since the late 1970s, which we relate to a change in food availability. Tissue fatty acid compositions show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. We, therefore, suggest that changes in pelagic-benthic coupling are likely due either to local changes in sea ice dynamics, mediated through bottom-up regulation exerted by sea ice on phytoplankton production, or to a mismatch between phytoplankton bloom and zooplankton grazing due to phenological change. Both possibilities allow a more regular and increased transfer of food to the seabed. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

Computer-assisted motivational interviewing for contraceptive use in women leaving prison: A randomized controlled trial

OBJECTIVES

Rates of unintended pregnancies in women with a history of incarceration are high and access to contraception before and after arrest can be limited. Individualized counseling can better prepare women for healthy pregnancy or provide an opportunity for contraceptive education and access within correctional facilities. In this study, we assessed the efficacy of motivational interviewing as an individualized intervention to increase the initiation of contraceptive methods while incarcerated and continuation after release in female inmates who wanted to avoid pregnancy for at least one year after release.

STUDY DESIGN

We performed an RCT in a population of incarcerated women who wanted to avoid pregnancy. Women were randomized to either a computer-assisted motivational interviewing intervention group (n = 119) or an educational video with counseling control group. (n = 113). The primary outcome was initiation of a method of birth control prior to release from the correctional facility.

RESULTS

Initiation of contraception was higher in the intervention group (56% vs. 42%, p = 0.03), but this difference was not significant after controlling for number of male partners within the year prior to incarceration. There was no difference between the groups in the rates of pregnancies or STIs or continuation of contraception after release, which was generally low (21%).

CONCLUSION

Computer-assisted motivational interviewing did not improve uptake or continuation of contraception in this study.

IMPLICATIONS

Periods of incarceration provide an opportunity to offer contraceptive services to women who want to avoid a pregnancy. Motivational interviewing may not be an effective method to affect contraceptive behaviors in this population. Future research should explore the family planning values and preferences of women who become involved with the correctional system.

LET dependence of the response of a PTW-60019 microDiamond detector in a 62MeV proton beam

This study was initiated following conclusions from earlier experimental work, performed in a low-energy carbon ion beam, indicating a significant LET dependence of the response of a PTW-60019 microDiamond detector. The purpose of this paper is to present a comparison between the response of the same PTW-60019 microDiamond detector and an IBA Roos-type ionization chamber as a function of depth in a 62MeV proton beam. Even though proton beams are considered as low linear energy transfer (LET) beams, the LET value increases slightly in the Bragg peak region. Contrary to the observations made in the carbon ion beam, in the 62MeV proton beam good agreement is found between both detectors in both the plateau and the distal edge region. No significant LET dependent response of the PTW-60019 microDiamond detector is observed consistent with other findings for proton beams in the literature, despite this particular detector exhibiting a substantial LET dependence in a carbon ion beam.

An in vivo, MRI-integrated real-time model of active contrast extravasation in acute intracerebral hemorrhage

BACKGROUND AND PURPOSE

The "spot sign" or contrast extravasation is strongly associated with hematoma formation and growth. An animal model of contrast extravasation is important to test existing and novel therapeutic interventions to inform present and future clinical studies. The purpose of this study was to create an animal model of contrast extravasation in acute intracerebral hemorrhage.

MATERIALS AND METHODS

Twenty-eight hemispheres of Yorkshire male swine were insonated with an MR imaging-guided focused sonography system following lipid microsphere infusion and mean arterial pressure elevation. The rate of contrast leakage was quantified by using dynamic contrast-enhanced MR imaging and was classified as contrast extravasation or postcontrast leakage by using postcontrast T1. Hematoma volume was measured on gradient recalled-echo MR imaging performed 2 hours postprocedure. Following this procedure, sacrificed brain was subjected to histopathologic examination. Power level, burst length, and blood pressure elevation were correlated with leakage rate, hematoma size, and vessel abnormality extent.

RESULTS

Median (intracerebral hemorrhage) contrast extravasation leakage was higher than postcontrast leakage (11.3; 6.3-23.2 versus 2.4; 1.1-3.1 mL/min/100 g; P<.001). Increasing burst length, gradient recalled-echo hematoma (ρ=0.54; 95% CI, 0.2-0.8; P=.007), and permeability were correlated (ρ=0.55; 95% CI, 0.1-0.8; P=.02). Median permeability (P=.02), gradient recalled-echo hematoma (P=.02), and dynamic contrast-enhanced volumes (P=.02) were greater at 1000 ms than at 10 ms. Within each burst-length subgroup, incremental contrast leakage was seen with mean arterial pressure elevation (ρ=0.2-0.8).

CONCLUSIONS

We describe a novel MR imaging-integrated real-time swine intracerebral hemorrhage model of acute hematoma growth and contrast extravasation.

Alpha-smooth muscle actin (alpha-SMA) and nestin expression in reactive astrocytes in multiple sclerosis lesions: potential regulatory role of transforming growth factor-beta 1 (TGF-beta1)

AIMS

Rapid and extensive activation of astrocytes occurs subsequent to many forms of central nervous system (CNS) injury. Recent studies have revealed that the expression profile of reactive astrocytes comprises antigens present during astrocyte development. Elevated levels of the injury-related cytokine transforming growth factor-beta 1 (TGF-beta1) secreted by microglial cells and invading macrophages have been correlated with the reactive astrocyte phenotype and glial scar formation.

METHODS

In the present study, the expression profile of alpha-smooth muscle actin (alpha-SMA) and nestin, two cytoskeletal proteins expressed during astrocyte development, was studied in multiple sclerosis (MS) lesions. In addition, alpha-SMA and nestin organization and expression were analysed in rat primary astrocyte cultures in response to TGF-beta1.

RESULTS

In active lesions and in the hypercellular margin of chronic active MS lesions, immunostaining for alpha-SMA revealed a subpopulation of reactive astrocytes, whereas the majority of reactive astrocytes expressed nestin. alpha-SMA and nestin expressing reactive astrocytes were in close relationship with TGF-beta1 expressing macrophages or microglia. In addition, TGF-beta1 expression within alpha-SMA or nestin expressing astrocytes was also detected. Our in vitro experiments showed that TGF-beta1 regulated the organization and expression of alpha-SMA and nestin in astrocytes.

CONCLUSIONS

Reactive astrocytes in active MS lesions re-express alpha-SMA and nestin. We suggest that the in vivo re-expression might be under regulation of TGF-beta1. These results further clarify the regulation of astrocyte activity after CNS injury, which is important for the astroglial adaptation to pathological situations.

Interactive multimedia and risk communication

As our understanding of risk factors and their interaction with individual susceptibility to disease improves, general messages designed to communicate risk seem increasingly ineffective and often misleading. Risk messages communicated through the mass media cannot convey an individual's personal susceptibility to preventable diseases or the seriousness of these diseases. The advent of new media technologies allows us to better reach the public with programs tailored to the needs and interests of individual users. Although similar in outward appearance to mass media, programs delivered through the Internet, CD-ROM, and computer kiosks offer the potential for vastly improved efficacy in communicating risk. This paper outlines the potential uses of interactive multimedia within the traditional goals of risk communication. A significant research endeavor, coupled with stronger avenues for dissemination, is recommended to achieve the potential of new media in a timely manner.

Prevention of cytokine accumulation in platelets obtained with the COBE spectra apheresis system

BACKGROUND AND OBJECTIVES

Febrile nonhemolytic transfusion reactions frequently accompany platelet transfusions and may be due to accumulation of cytokines mediating inflammation during storage of platelet concentrates (PCs). We wished to determine whether PCs collected using the COBE(R) SpectraTM Apheresis System (Version 4) were sufficiently leukocyte reduced (LR) to limit cytokine accumulation during storage.

MATERIALS AND METHODS

Cytokine accumulation - interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha) - and release of platelet alpha-granule - P-selectin, transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor AB (PDGF-AB), von Willebrand factor (vWf) - or dense granule (serotonin) markers were investigated during a 7-day storage period comparing apheresis-collected, LR PCs (LR PCs) and random donor platelets prepared from whole blood (WB).

RESULTS

Leukocyte counts were reduced 99.95% comparing LR PCs (5.7 x 10(5)/l) and WB PCs (1.09 x 10(9)/l). Little or no accumulation of leukocyte-derived cytokines was observed in LR PCs during storage in contrast to WB PCs. A reduction in the release of platelet alpha-granule proteins, such as P-selectin, TGF-beta1 and PDGF-AB, was observed on day 0 for LR PCs compared to WB PCs with little or no difference observed from day 3 to 7. Plasma vWf levels were higher in LR PCs compared to WB PCs on days 0-7.

CONCLUSION

Leukocyte levels in PCs collected with the COBE Spectra Apheresis System are sufficiently low to limit cytokine production during 7 days of storage.

Epo regulates erythroid proliferation and differentiation through distinct signaling pathways: implication for erythropoiesis and Friend virus-induced erythroleukemia

We have recently isolated the erythroleukemic cell line, HB60-5, that proliferates in the presence of erythropoietin (Epo) and stem cell factor (SCF), but undergoes terminal differentiation in the presence of Epo alone. Ectopic expression of the ets related transcription factor Fli-1 in these cells resulted in the establishment of the Epo-dependent cell line HB60-ED that proliferates in the presence of Epo. In this study, we utilized these two cell lines to examine the signal transduction pathways that are activated in response to Epo and SCF stimulation. We demonstrate that Epo, but not SCF, phosphorylates STAT-5 in both HB60-5 and HB60-ED cells. Interestingly, SCF activates the Shc/ras pathway in HB60-5 cells while Epo does not. However, both Epo and SCF are capable of activating the Shc/ras pathway in HB60ED cells. Furthermore, enforced expression of gp55 in HB60-5 cells by means of infection with the Spleen Focus Forming virus-P (SFFV-P), confers Epo independent growth, which is associated with the up-regulation of Fli-1. Activation of the Shc/ras pathway is readily detected in gp55 expressing cells in response to both Epo and SCF, and is associated with a block in STAT-5B tyrosine phosphorylation. These results suggest that STAT-5 activation, in the absence of Shc/ras activation, plays a role in erythroid differentiation. Moreover, Fli-1 is capable of switching Epo-induced differentiation to Epo-induced proliferation, suggesting that this ets factor regulated genes whose products modulate the Epo-Epo-R signal transduction pathway.

Carpal tunnel syndrome caused by Mycobacterium szulgai

We describe 2 cases of infection due to Mycobacterium szulgai revealed by a carpal tunnel syndrome (CTS) that was the only clinical manifestation. Both patients regularly cleaned their fish tank with bare hands. The diagnosis was made by isolation of M. szulgai from synovium. The cause of the CTS was a synovitis. Previous synovectomies were ineffective. Improvement was observed with antibiotic treatment. The only way to diagnose this unusual infection is to perform histology of synovium and to isolate the mycobacteria from synovium culture.

Detection of depression in elderly hospitalized patients in emergency wards in France using the CES-D and the mini-GDS: preliminary experiences

OBJECTIVE

The purpose of this study was to evaluate the mini-GDS and the CES-D as instruments to detect depression in elderly hospitalized patients in emergency wards in France.

METHODS

The CES-D was used on two cohorts of 60 non-cognitively impaired patients aged 70 or more. The mini-GDS was also used on the second of the two cohorts administered by a medical intern. These ratings were compared with a diagnosis of depressive disorder by ICD-10 criteria.

RESULTS

The study population had a high (58%) prevalence of depression and a low level of active psychiatric referral. Mini-GDS and CES-D scores were well correlated (0.72, p < 0.001); the mini-GDS, with a cutoff score of 1, gave optimum sensitivity (88%) and specificity (63%).

CONCLUSION

The use of the mini-GDS may aid the detection of depression in patients in emergency wards.

Lymphatic endothelial tumors induced by intraperitoneal injection of incomplete Freund's adjuvant

Endothelial cells form the inner lining of blood and lymphatic vessels. In mice, only tumors of the blood vessel endothelium (haemangiomas) have been thus far reported. Here we describe a highly reproducible method for the induction of benign tumors of the lymphatic endothelial cells (lymphangiomas) in mice by intraperitoneal injection of incomplete Freund's adjuvant. Morphological and histopathological studies of the lesions revealed the presence of cells at various levels of vascular development. The lymphangiomas developed in the peritoneal cavity and expressed the endothelial markers CD31/PECAM (platelet endothelial cell adhesion molecule), CD54/ICAM-1 (InterCellular Adhesion Molecule-1), and CD102/ICAM-2, as well as the vascular endothelial growth factor (VEGF) receptor Flk-1, the endothelial cell specific receptors Tie-1 and Tie-2 and the lymphatic endothelial cell specific Flt4 receptor as shown by in situ hybridization. The Flk-1 and Flt4 receptors were also identified in immunoblots of the tumors and in cells cultured from them. When induced in beta-galactosidase knock-in Flt4(+/-) mice, the tumor endothelia could be stained blue in a number of tumor cells although the staining was of lower intensity than in normal lymphatic vessels. The tumor-derived cells could be propagated in vitro and they spontaneously differentiated, forming vessel-like structures. Murine lymphangiomas thus represent a highly reproducible and convenient source of lymphatic endothelial cells.

Abducens palsy after an intrathecal glucocorticoid injection. Evidence for a role of intracranial hypotension

We report a case of abducens palsy eight days after an intrathecal glucocorticoid injection followed by post-lumbar puncture syndrome. T1-weighted magnetic resonance imaging scans showed marked diffuse postgadolinium enhancement of the supra- and infratentorial meninges consistent with intracranial hypotension syndrome. The palsy resolved almost completely and a repeat magnetic resonance imaging scan done after four months was normal. The mechanism of the meningeal thickening and contrast enhancement is discussed.

[Articular and tendon manifestations indicating the stage of rheumatoid polyarthritis]

Synovial inflammation and the destruction which results from recurrent and chronic inflammation lead to arthritis and tenosynovitis. Clinical manifestations are bilateral and symmetrical, affecting virtually all joints. The hands and the feet are the main targets. Cervical involvement should be routinely investigated. X-rays demonstrate the erosion and deformation caused by rheumatoid arthritis. Altogether, the manifestations of the disease constitute a distinct and painful handicap. Treatment should be undertaken as early as possible in the course of rheumatoid arthritis in an attempt to avoid evolution toward irreversible destruction.

In vitro cytotoxic effects of 4,4'-bipyridyl on normal human keratinocytes

Recent epidemiological studies have brought to light a possible link between premalignant or neoplastic skin lesions (Bowen disease, squamous carcinoma) and occupational exposure to 4,4'-bipyridyl (4,4'B), a precursor in the synthesis of paraquat herbicide. The present study used a serum-free cell culture of normal human keratinocytes (NHK) and two skin-equivalent models to test the effects of exposure to different concentrations of 4,4'B. Cytotoxicity of 4,4'B on NHK was measured by neutral red release assay. Superoxide dismutase (SOD) activity and cell cycle were analyzed in exposed and nonexposed NHK cultures. Histological and immunohistological tests enabled evaluation of differentiation and proliferation effects in reconstructed-skin models. Results showed that significant cytotoxicity occurred after 5 to 11 days' exposure to 4,4'B concentrations of 10(-6)-10(-3) mol/L (IC50 between 10(-3) and 10(-4) mol/L 4,4'B after 11 days). Parallel modifications of SOD activity were recorded. Histological and immunohistological analysis revealed dose-related 4,4'B effects in reconstructed skin models. This involved abnormal terminal differentiation, connected with filaggrin expression, observed in skin models exposed to 10(-7) and 10(-6) mol/L 4,4'B. However, no modification of cell cycle or dysplasia was detected as a result of exposure to 4,4'B. Thus, 4,4'B appears to be cytotoxic for NHK, but as an isolated contaminant, and is unable to induce keratinocyte dysplasia in vitro. These preliminary results do not exclude a cocarcinogenic action of 4,4'B (with UVB for example).

Analytical findings in a suicide involving sodium azide

A 47-year-old laboratory assistant ingested approximately 9 g of sodium azide powder and died 4 h later at a hospital. A high-performance liquid chromatographic method using diode-array detection has been developed for the determination of an azide benzoyl derivative in blood (after a simple deproteinization) and in several tissues (after homogenization in a neutral buffer and deproteinization of the supernatant). The blood concentration in this case was lower than those previously published. The highest azide concentration was found in lung tissue. A complete toxicological screening revealed the presence of cyanide in blood, which has been previously reported twice, but for the first time, it was confirmed by mass spectrometry. Whether the production of cyanide in the presence of azide took place in vivo or postmortem remains unknown; the nature of the metabolic pathway involved also remains unknown.

Endothelial-specific gene expression directed by the tie gene promoter in vivo

The tie gene encodes a receptor tyrosine kinase that is expressed in the endothelium of blood vessels, particularly during embryonic development and angiogenesis in adults. We have cloned and characterized the mouse tie gene and isolated the human and mouse tie promoters. The promoter activities of human and mouse tie were analyzed using luciferase reporter gene constructs in transfected cell lines and beta-galactosidase constructs in transgenic mice. In transfection assays of cultured cells, both human and mouse promoter DNA fragments showed activity that was not restricted to endothelial cells. In contrast, in transgenic mice both promoters directed expression of the reporter gene to endothelial cells undergoing vasculogenesis and angiogenesis. In adult mice, tie promoter activity in lung and many vessels of the kidney was as high as in the vessels of the corresponding embryonic tissues, whereas in the heart, brain and liver, tie promoter activity was downregulated and restricted to coronaries, cusps, capillaries, and arteries. Our results show that the endothelial cell-type specificity of the tie promoter in vivo can be transferred to heterologous genes by using relatively short promoter fragments. The tie promoter, thus, has useful properties for potential gene therapy.

Expression of the fms-like tyrosine kinase 4 gene becomes restricted to lymphatic endothelium during development

We have recently cloned the human fms-like tyrosine kinase 4 gene FLT4, whose protein product is related to two vascular endothelial growth factor receptors FLT1 and KDR/FLK1. Here the expression of FLT4 has been analyzed by in situ hybridization during mouse embryogenesis and in adult human tissues. The FLT4 mRNA signals first became detectable in the angioblasts of head mesenchyme, the cardinal vein, and extraembryonally in the allantois of 8.5-day postcoitus (p.c.) embryos. In 12.5-day p.c. embryos, the FLT4 signal decorated developing venous and presumptive lymphatic endothelia, but arterial endothelia were negative. During later stages of development, FLT4 mRNA became restricted to vascular plexuses devoid of red cells, representing developing lymphatic vessels. Only the lymphatic endothelia and some high endothelial venules expressed FLT4 mRNA in adult human tissues. Increased expression occurred in lymphatic sinuses in metastatic lymph nodes and in lymphangioma. Our results suggest that FLT4 is a marker for lymphatic vessels and some high endothelial venules in human adult tissues. They also support the theory on the venous origin of lymphatic vessels.

[Clinical pitfalls in the diagnosis of microcrystalline arthritis]

Diagnosis of microcrystalline arthritis often is based on joint punctures, performed whenever possible. The clinical features of the crises may suggest diagnosis, but is not decisive. The course before or during treatment is not indicative and cannot fully exclude infection when the patient is seen during a crisis; arthritis with one or several microcrystals is possible, as in forms associated with joint infection. For well-oriented management, good knowledge of such diagnostic difficulties is necessary.

Single-dose pharmacokinetics of amineptine and of its main metabolite in healthy young adults

The pharmacokinetics of the tricyclic antidepressant amineptine (Survector) and its main metabolite were studied in 12 young healthy adults (6 men, 6 women; mean age 35.8 yr). Plasma samples were taken over 24 h following a single oral dose of 100 mg amineptine chloryhdrate. Plasma levels of both compounds were determined by means of high performance liquid chromatography. Amineptine was rapidly absorbed. Mean peak plasma concentrations of amineptine and its metabolite occurred 1 h and 1.5 h, respectively, after product administration. The mean apparent volume of distribution was large: 2.4 l.kg-1. Elimination was rapid; the mean half-lives of the 2 compounds were short: 0.8 h for amineptine and 2.5 h for the metabolite. The mean apparent plasma clearance of amineptine was high (124.8 l.h-1). When the results were adjusted for body weight and surface area, no significant difference in pharmacokinetic parameters was found between men and women. Given its pharmacokinetic characteristics there is no risk of amineptine accumulation and thus it is a particularly easy drug to manage. A standard dosage of amineptine was defined for use in healthy young adults.