Increased availability of paracetamol in Sweden and incidence of paracetamol poisoning: using laboratory data to increase validity of a population-based registry study

PURPOSE

To estimate the incidence trend and outcome of paracetamol poisoning, in relation to increased availability of paracetamol from non-pharmacy outlets in 2009.

METHOD

Patients' serum paracetamol results over 14 years (2000-2013) from 20 (out of 21) regions in Sweden were linked to national registers of hospital care, cause of death, and prescriptions. Paracetamol poisonings were defined by serum paracetamol levels, hospital diagnoses, or cause of death. The change in incidence of poisonings following increased availability of paracetamol was analysed by using segmental regression of time series.

RESULTS

Of the 12 068 paracetamol poisonings, 85% were classified as intentional self-harm. Following increased availability from non-pharmacy outlets, there was a 40.5% increase in the incidence of paracetamol poisoning, from 11.5/100 000 in 2009 to 16.2/100 000 in 2013. Regression analyses indicated a change in the trend (p < 0.0001) but not an immediate jump in the incidence (p = 0.5991) following the increased availability. Adjusting for trends in hospital episodes for self-harm, suicides, and the sales volume of paracetamol did not influence the result. All-cause mortality at 30 days (3.2%) did not change over time.

CONCLUSIONS

The incidence of paracetamol poisoning in Sweden has increased since 2009, contrasting the decreased incidence in the period of 2007-2009. The change in trend was temporally associated with the introduction of availability of paracetamol from non-pharmacy outlets but did not appear to be related to sales volume of paracetamol or general trends in self-harm or suicides. © 2017 Commonwealth of Australia. Pharmacoepidemiology and Drug Safety © 2017 John Wiley & Sons, Ltd.

[Overdose of modified-release paracetamol calls for changed treatment routines. New guidelines from the Swedish Poisons Information Centre]

Overdose of modified-release paracetamol calls for changed treatment routines. New guidelines from the Swedish Poisons Information Centre  The sales of modified-release paracetamol tablets are steadily increasing in Sweden as are the number of overdose cases with this formulation. The Swedish Poisons Information Centre has noted that the standard treatment protocol with N-acetylcysteine (NAC), which is based on overdoses with immediate-release paracetamol formulations, is often inadequate in this setting. In this paper, an adult who overdosed on 66.5 grams of modified-release paracetamol tablets and developed severe liver impairment (max ALT 6,660 U/l) despite timely and rigorous NAC treatment is presented. The patient's peak S-paracetamol of 2,800 µmol/l was delayed to 19 hours post-ingestion. Moreover, a pharmacokinetic and clinical study of similar cases showed that seven (21%) of the 34 patients who received NAC treatment within 8 hours after ingestion developed liver impairment. Finally, new Swedish guidelines for management of these cases are presented. The guidelines are also available on www.giftinfo.se.

Gender differences in secondary prevention of coronary heart disease: reasons to worry or not?

OBJECTIVE

To analyse potential gender differences in cardiovascular risk factors and treatment patterns, reflecting clinical practice in secondary prevention.

DESIGN

Observational national study during 3 years of patients eligible for secondary prevention of coronary heart disease (CHD).

SETTING

Fifty-two healthcare districts in Sweden, involving primary health care and hospitals in collaboration, participating in a national quality assurance programme for the prevention of CHD.

SUBJECTS

A national sample of male and female patients surviving acute myocardial infarction, or following CABG/PTCA interventions for CHD, controlled at 3-6 months (n = 9135) and 12 months (n = 4802) of follow-up. The proportion of female patients (25%) did not differ between visits.

MAIN OUTCOME MEASURES

Self-reported data on lifestyle, drug treatment and cardiovascular risk factor levels after consultation in general practice or at hospital policlinics.

RESULTS

No major gender differences were recorded in risk factor levels or in cardiovascular drug treatment patterns at 12 months of follow-up. Female patients participated in educational programmes to improve lifestyle to a higher degree than males (52.0 vs 45.1%), but after 1 year were more often (p < 0.001) self-reported smokers (11.7 vs 8.4%). Female patients showed higher levels of blood pressure, total cholesterol and HDL cholesterol, but not LDL cholesterol compared to male patients.

CONCLUSIONS

In general, a gender-equal level of lipid control and access to medical drug treatment has been established for patients in secondary prevention from a national sample in Sweden, followed for 1 year after CHD manifestations and related interventions.

[Quality assurance of secondary prevention of coronary artery disease. Ongoing project offers possibilities for improved treatment]

Regional programs for secondary prevention of coronary artery disease have been under development for nearly a decade in Sweden. To achieve maximum adherence these programs were created in close collaboration between hospital and primary care physicians. The programs are local applications of national guidelines and aim to support compliance among both patients and physicians. In January 1998 the Swedish Society of Cardiology and the Swedish Association of General Practice launched a program for quality control and quality assurance of these initiatives. So far, 51 of 79 districts have joined the program. Patients' diaries used for risk factor registration contain 7 report cards on the management of risk factors and medication. These cards are sent to a central registry upon release from the hospital, after 3-6 months, and annually for 5 years. Results from the first year point to differences between the various districts with respect to compliance with both local programs and European guidelines. Overall, results are promising and indicate that this program is successful and leads to improved management of patients with coronary artery disease.

A missense mutation in the desmin rod domain is associated with autosomal dominant distal myopathy, and exerts a dominant negative effect on filament formation

In some myopathies of distal onset, the intermediate filament desmin is abnormally accumulated in skeletal and cardiac muscle. We report the first point mutation in desmin cosegregating with an autosomal dominant form of desmin-related myopathy. The L345P desmin missense mutation occurs in a large, six generation Ashkenazi Jewish family. The mutation is located in an evolutionarily highly conserved position of the desmin coiled-coil rod domain important for dimer formation. L345P desmin is incapable of forming filamentous networks in transfected HeLa and SW13 cells. We conclude that the L345P desmin missense mutation causes myopathy by interfering in a dominant-negative manner with the dimerization-polymerization process of intermediate filament assembly.

Pediatric rhabdomyosarcomas express the intermediate filament nestin

Previous findings that the intermediate filament nestin is expressed in immature skeletal muscle cells prompted us to compare the staining patterns of nestin and desmin in rhabdomyosarcomas (RMSs) and in other small cell tumors of infancy. We found that nestin immunoreactivity was present in all of 29 examined typical RMSs, which also expressed desmin. Two undifferentiated tumors, primarily suspected to be RMSs, expressed nestin, but not desmin. One of these nestin-positive, desmin-negative tumors was positive for the expression of the myogenic regulatory gene MyoD and is considered to represent an undifferentiated RMS. The other, a paratesticular tumor, did not contain transcripts for MyoD, and most likely does not represent a RMS. In several RMSs and nonmuscle tumors, a z-disc-associated nestin immunoreactivity occurred as a paramalignant phenomenon in cross-striated muscle fibers adjacent to the tumor cells. Our findings indicate that nestin, although present also in tumors of the central and peripheral nervous systems, as well as in endothelial cells and in some muscle cells adjacent to tumors, is a useful complementary marker for RMS, particularly in very undifferentiated desmin-negative tumors.

Distribution of nestin in the developing mouse limb bud in vivo and in micro-mass cultures of cells isolated from limb buds

Early skeletal muscle development is accompanied by changes in the composition of the cytoskeleton. In this report we analyze the distribution of the intermediate filament nestin in the developing mouse limb buds in vivo and in mesenchymal cells isolated from limb buds in vitro. The subcellular distribution of nestin mRNA and protein in muscle cells was also analyzed. We find a shift in nestin expression during early limb bud development. At embryonic day 11 (E11), low levels of nestin (protein) were expressed in the mesenchymal cells of the developing limb bud. Later, nestin mRNA and protein were down-regulated in the mesenchymal condensations undergoing chondrogenesis (E12 and E13), but remained expressed predominantly in the ectodermal cells and in the differentiating myoblasts. At E18, only muscle fibres, endothelial cells and nerves were nestin positive. This shift in expression was reproduced in vitro, in micro-mass cultures of mesenchymal cells. In E11 cultures, nestin protein was initially expressed in all cells. Upon formation of cartilage foci (after 2-3 days in culture), nestin immunoreactivity was not observed in cartilage, and low levels were detected in the cells located between the foci. A subpopulation of mono- and multinucleated cells, peripheral to the cartilage nodules, expressed the muscle-specific intermediate filament desmin protein together with high levels of nestin protein. The proportion of nestin-expressing cells could be changed by addition of specific signalling molecules. Insulin-like growth factors I and II (IGF I and II) increased the number of nestin-positive cells, while basic fibroblast growth factor (FGF) reduced the number of nestin-expressing cells. Finally, we present evidence for a different subcellular localization of nestin protein and mRNA: the mRNA is predominantly located in the ends of the muscle cell, whereas the protein is found in the central region. Intracellular localization of nestin mRNA may constitute an additional level of regulation of the cytoskeleton during muscle development.

Citalopram overdose--review of cases treated in Swedish hospitals

BACKGROUND

The toxic effects of acute citalopram overdose are reported by the Swedish Poisons Information Centre.

DESIGN

Case reports received from Swedish hospitals during 1995 have been analyzed. Forty-four cases of pure citalopram intoxication have been studied in detail.

RESULTS

At doses below 600 mg, mild symptoms were observed. Doses above 600 mg caused ECG abnormalities and convulsions in some patients, while doses greater than 1900 mg caused such symptoms in all patients.

CONCLUSIONS

The findings are consistent with previous reports claiming that selective serotonin reuptake inhibitors are less toxic compared to tricyclic antidepressants. However, there is a risk of developing serious symptoms when large doses have been ingested.

Tenascin-C expression correlates with macrophage invasion in Duchenne muscular dystrophy and in myositis

Tenascin-C (TN-C) is an extracellular matrix protein expressed during development in several tissues, but restricted to only a few areas in normal adult tissues. By immunizing mice with human fetal myoblasts we generated a monoclonal antibody to TN-C and mapped the epitope to the aminoterminal end containing EGF-like repeats. Using this antibody we detected by immunohistochemistry TN-C in the epimysium and perimysium of human fetal muscles, as well as in nonfibrillar deposits in myoblast cultures. In situ hybridization did not reveal any signal within human fetal muscle groups, suggesting that non-muscle cells synthesize the majority of the tenascin that localizes in and around human fetal muscle. Immunohistochemical analysis of muscle biopsies from Duchenne/Becker muscular dystrophy and myositis patients revealed that TN-C is expressed in skeletal muscle. Although the patterns of TN-C immunoreactivity were quite different in the two disease entities, the endomysial TN-C reactivity in both DMD/BMD and in myositis invariably correlated with the presence of macrophages.

Analysis of fibronectin and vitronectin receptors on human fetal skeletal muscle cells upon differentiation

The role of fibronectin (FN) and vitronectin (VN) receptors for cell adhesion and matrix assembly was analyzed during human fetal myogenesis in vivo and in vitro. In human fetal muscle at 10 weeks gestational age FN and laminin are present in the extracellular matrix. Analysis of the integrin repertoire at this developmental stage reveals that the differentiated muscle cells in vivo express alpha 5 and alpha 6 integrins, but not alpha v, alpha 1, and alpha 3 integrins. However, in vitro cultured myoblasts (G6) isolated from the same gestational age express alpha v, alpha 1, and alpha 3 integrins in addition to alpha 5 and alpha 6 integrins. A more detailed analysis of FN and VN receptors in vitro shows that the localization of different alpha v heterodimers into focal contacts is differently regulated. Alpha v beta 1, and alpha v beta 3, are present at focal contacts throughout in vitro myogenesis whereas alpha v beta 5 appears to depend on an endogenously produced factor to localize to focal contacts. The alpha v beta 1, alpha v beta 5, and alpha 3 beta 1 heterodimers, often reported not to focalize, did form focal contacts in G6 cells, indicating that these myoblasts possess components facilitating the formation of cytoskeletal linkages containing these integrins. Alpha 5 beta 1 colocalized with FN in myoblast cultures, whereas myotubes lacked both FN and alpha 5 beta 1 on the cell surface. In summary, we show that concomitant with in vitro differentiation of G6 cells, FN matrix contacts are abolished, but vitronectin receptors continue to fulfill an anchoring function during the differentiation process in vitro. Further studies are needed to assess the relative importance of the FN and VN binding integrins for the differentiation process in comparison with the laminin-binding integrins alpha 6 and alpha 7, also present on these cells.

Up-regulation of a novel integrin alpha-chain (alpha mt) on human fetal myotubes

Integrin expression and distribution was studied in cloned human fetal G6 myoblasts and myotubes. Immunoprecipitation of beta 1 integrins from surface iodinated and metabolically labeled G6 cells typically showed a five-fold induction of a beta 1 integrin associated protein upon differentiation. Under non-reducing conditions this beta 1 associated protein migrated as 145 kD. No such beta 1 associated protein was observed in the myogenic L8 rat cell line, before or after differentiation. The beta 1 integrin associated cell surface protein present in G6 myotubes remained associated with the beta 1 subunit in the presence of 1% Triton X-100 and 0.5 M NaCl. Like integrin alpha-chains, the protein dissociated from the beta 1 integrin subunit at low pH. Immunoprecipitation of G6 myotubes further indicated the presence of alpha 1, alpha 3, alpha 5, and alpha v integrins, and small amounts of alpha 4 and alpha 6 integrins. Immunodepletion with integrin alpha-chain antibodies to alpha 1, alpha 3, alpha 4, alpha 5, alpha 6, and alpha v integrin chains could not deplete the beta 1 integrin associated protein, indicating that it did not interact with any of these known integrin heterodimers. Upon treatment with reducing agents, the beta 1 integrin associated protein migrated in SDS-PAGE as a 155 kD protein. The decreased mobility in SDS-PAGE upon reduction is a feature shared with alpha 1, alpha 2, and alpha 9 integrin alpha-chains. Antibodies to alpha 1 immunoprecipitated an integrin heterodimer distinct from the 155 kD protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Colocalization of nestin and vimentin/desmin in skeletal muscle cells demonstrated by three-dimensional fluorescence digital imaging microscopy

During skeletal muscle development three intermediate filament proteins are expressed: nestin, vimentin, and desmin. Vimentin and desmin belong to the class III intermediate filaments and are closely related to each other, whereas nestin is a more distantly related, class VI, intermediate filament. It was previously observed by conventional immunocytochemistry that the intracellular patterns of nestin, desmin, and vimentin appeared indistinguishable, despite nestin's more distant evolutionary relationship. We here extend this analysis by applying three-dimensional fluorescence digital imaging microscopy to compare the intracellular distribution of nestin with that of desmin, vimentin, actin, and tubulin in G6 human fetal skeletal muscle cells. We show that in vitro differentiation of G6 cells can produce an intermediate filament expression pattern similar to that observed during myogenesis in vivo, i.e., downregulation of vimentin but not of nestin and desmin during myotube maturation. The image analysis demonstrated that the degree of overlap between nestin and desmin/vimentin was very extensive in myoblasts and in multinucleate myotubes in all regions of the cells. In contrast, nestin did not colocalize with tubulin or actin in G6 myoblasts. In particular, nestin immunoreactivity was not detected at the microtubule-organizing center, and it was only sparsely observed at the cell periphery where actin stress fibers were seen. Our data lend further support to the notion that nestin interacts very closely with the two more distantly related class III intermediate filament proteins desmin and vimentin in the entire muscle cell, before and after myotube formation. A comparison of conserved amino acid residues in the different IFs suggest that charged amino acid residues in the alpha-helical rod domain may play a role in the interaction.

Myofibers from Duchenne/Becker muscular dystrophy and myositis express the intermediate filament nestin

The intermediate filament nestin is transiently expressed in developing skeletal muscle. In the present investigation, we analyzed by immunohistochemistry the presence of nestin, as well as vimentin and desmin, in skeletal muscle affected by two diseases characterized by various degrees of necrosis and muscle regeneration: Duchenne/Becker muscular dystrophy and myositis. Nestin-positive areas were found in all analyzed muscle biopsies of both diseases. The same areas were, in most cases, also positive for vimentin and stained more intensely for desmin than surrounding myofibers. Only nestin was found specifically in myopathic muscle fibers; vimentin was in addition present in muscle fibroblasts and desmin in all myofibers. The areas staining positive for nestin were typically basophilic, small-diameter myofibers, often with centrally located nuclei. With the interesting exception of a 73-year-old healthy control with abundant ring fibers, nestin was not detected in the muscle of healthy controls. The intracellular distribution of nestin in the myopathic muscle fibers, as well as in the ring fibers, was confined to the vicinity of Z-bands. The presence of nestin protein in myopathic regenerating areas and in ring fibers correlated more closely to the presence of desmin than to vimentin immunoreactivity. Our results suggest that nestin is specifically expressed in newly formed muscle fibers also during regeneration, and that nestin may serve as a useful marker of regenerating muscle fibers in pathological conditions.

Moclobemide overdose

Moclobemide is a recently introduced short-acting, selective and reversible monoamine oxidase inhibitor, type A, with few and mild side-effects at therapeutic doses. Fifteen reported cases of moclobemide overdose were studied in detail and are presented here. While pure mechanism overdosage seems benign, a combination with tricyclic antidepressants may result in serious poisoning even when the moclobemide overdose is modest.