Prevalent presence of periodic actin–spectrin-based membrane skeleton in a broad range of neuronal cell types and animal species

Actin, spectrin, and associated molecules form a periodic, submembrane cytoskeleton in the axons of neurons. For a better understanding of this membrane-associated periodic skeleton (MPS), it is important to address how prevalent this structure is in different neuronal types, different subcellular compartments, and across different animal species. Here, we investigated the organization of spectrin in a variety of neuronal- and glial-cell types. We observed the presence of MPS in all of the tested neuronal types cultured from mouse central and peripheral nervous systems, including excitatory and inhibitory neurons from several brain regions, as well as sensory and motor neurons. Quantitative analyses show that MPS is preferentially formed in axons in all neuronal types tested here: Spectrin shows a long-range, periodic distribution throughout all axons but appears periodic only in a small fraction of dendrites, typically in the form of isolated patches in subregions of these dendrites. As in dendrites, we also observed patches of periodic spectrin structures in a small fraction of glial-cell processes in four types of glial cells cultured from rodent tissues. Interestingly, despite its strong presence in the axonal shaft, MPS is disrupted in most presynaptic boutons but is present in an appreciable fraction of dendritic spine necks, including some projecting from dendrites where such a periodic structure is not observed in the shaft. Finally, we found that spectrin is capable of adopting a similar periodic organization in neurons of a variety of animal species, including Caenorhabditis elegans, Drosophila, Gallus gallus, Mus musculus, and Homo sapiens.Actin is critically involved in the regulation of neuronal polarization, differentiation, and growth of neuronal processes, cargo trafficking, and plasticity of synapses (1–3). Spectrin is an actin-binding protein that is important for the development and stabilization of axons and maintenance of neuronal polarization (4–6). In Caenorhabditis elegans, spectrin is important for the stability and integrity of axons under mechanical stress (4, 6) and for mechanosensation (6), and spectrin depletion results in axon breakage during animal locomotion (4). In Drosophila, spectrin has been shown to be involved in axonal path finding (7) and stabilization of presynaptic terminals (8). In mice, spectrin null mutations are embryonically lethal, and neurons with spectrin knockdown display defects in axonal initial segment assembly (5, 9, 10).Actin and spectrin form a 2D polygonal lattice structure underneath the membrane of erythrocytes (11). Recently, a novel form of actin–spectrin-based submembrane skeleton structure was discovered in neuronal axons (12) using superresolution STORM imaging (13, 14). This membrane-associated periodic skeleton (MPS) has been observed in both fixed and live cultured neurons (12, 15, 16) and in brain tissue sections (12). In this structure, short actin filaments are organized into repetitive, ring-like structures that wrap around the circumference of the axon with a periodicity of ∼190 nm; adjacent actin rings are connected by spectrin tetramers, and actin short filaments in the rings are capped by adducin (12). This structure also appears to organize other associated molecules, such as ankyrin and sodium channels, into a periodic distribution in axons (12, 16). During neuronal development, MPS originates from the axonal region proximal to the soma and propagates to distal axonal terminals (16). At a relatively late stage during development, specific isoforms of ankyrin and spectrin molecules, ankyrin-G and βIV spectrin, are recruited to the axon initial segment (AIS) (17, 18), and these molecules are also assembled into the MPS structure, adopting a similar periodic distribution (16, 19). As in the AIS, this periodic structure is also present in the nodes of Ranvier (20). This periodic skeletal structure has been shown to preferentially form in axons compared with dendrites in primary neuronal cultures: actin and spectrin typically form a long-range, periodic lattice structure throughout the entire axonal shaft, except for the very distal region near the growth cone, in essentially all observed axons. In contrast, such a periodic structure was observed in only a small fraction (∼10–30%) of dendrites and typically appeared as short, isolated patches in portions of these dendrites (16, 20). The local concentration of spectrin is a key determinant for the preferential formation of MPS in axons: in wild-type neurons, βII spectrin is enriched in axons, and artificially increasing the concentration of βII spectrin through overexpression is sufficient to induce the formation of MPS in all dendrites (16). Ankyrin-B appears to be an important regulator of this structure: in ankyrin-B knockout mice, βII spectrin becomes evenly distributed between axons and dendrites, leading to the formation of the long-range MPS structure in all dendrites (16) without perturbing the MPS structure in axons (16, 21).The ubiquitous expression of spectrin in the nervous systems of nearly all animal species (22) raises the questions of how widespread the MPS structure is in different nervous system cell types and distinct subcellular compartments and of how conserved this structure is across different animal species. A recent paper reports the presence of periodic actin structures in several nervous system cell types from rodents (23). Here we investigated these questions regarding the prevalence and conservation of the MPS structure by examining the distribution of spectrin in many different types of rodent neurons and glial cells and across a variety of organisms ranging from C. elegans to Homo sapiens. Furthermore, we examined the distribution of spectrin in presynaptic and postsynaptic compartments of axons and dendrites, respectively, to shed light on the relation between the MPS structure and synapses.     

McCune–Albright syndrome,natural history and multidisciplinary management in a series of 14 pediatric cases

BackgroundMcCune–Albright syndrome is a rare disorder characterized by endocrine disorders, café-au-lait spots and fibrous dysplasia of bone that occurs early in life.MethodsA series of 14 pediatric cases were followed between 1994 and 2013 by the competence center for rare endocrine diseases and constitutional bone diseases at CHU de Nancy (France). The diagnosis is based on the presence of at least two symptoms.ResultsThe mean follow-up was 6 years (1–17 years). The sex ratio was six girls per boy. The incidence was 0.28 cases/million population/year. Mean age at diagnosis was 6 years. A mutation in the GNAS gene was found in 33% of patients tested. Gonadal involvement (13/14 cases), including early peripheral puberty and ovarian cysts in girls (82%) occurred on average at 4 years of age. Bone involvement (10/14 cases) appeared on average at 5 years of age and was most often multiple (80%) with fracture risk, and the skull, with a neurosensory risk.ConclusionClinical definition and methods of screening and monitoring can be improved to allow for an earlier intervention. It must be multidisciplinary and take into account the disability and quality of life of the patient.     

Malignancy in Behçet's disease: a report of 13 cases and a review of the literature

Beh?et's disease (BD) has rarely been reported in association with malignant diseases. In most cases the autoimmune nature of the disease itself or immunosuppressive drug use has been blamed for malignant transformation. We report 13 cases of BD concurrent with neoplastic disease as well as treatment-related morbidities in this particular patient group. Between 1986 and 1999, 400 patients were diagnosed as having BD in Hacettepe University Hospitals. Of these 13 patients, 3.25% developed malignant diseases within a median follow-up time of 9.8 years. Solid tumors were diagnosed in 10 patients and haematological or lymphoid malignancies in three. Surgery was performed in seven patients, whereas radiotherapy was applied in six and chemotherapy in eight. A literature review revealed 27 cases of BD associated with malignancies, mostly lymphoid or haematological. Ten of our cases were solid tumors, and to our knowledge most of these are the first reported cases of specific malignancies concurrent with BD. Treatment-related morbidities were wound infection as surgical morbidity in one patient (1/7) and radiotherapy-related morbidity in three (3/6) patients in a median follow-up time of 2 years. Solid tumors in addition to lymphoid and haematological malignancies are also seen during the course of BD. Radiation therapy may cause severe late toxicities in the presence of BD. Chemotherapy and surgery are fairly safe for the treatment of malignancies in BD patients.     

Accumulation of mitochondrial DNA mutations in ageing,cancer, and mitochondrial disease: is there a common mechanism?

In man, cells accumulate somatic mutations of mitochondrial DNA (mtDNA) as part of normal ageing. Although the overall concentration of mutant mtDNA is low in tissue as a whole, very high numbers of various mtDNA mutations develop in individual cells within the same person, which causes age-associated mitochondrial dysfunction. Some tumours contain high numbers of mtDNA mutations that are not present in healthy tissues from the same individual. The proportion of mutant mtDNA also rises in patients with progressive neurological disease due to inherited mtDNA mutations. This increase parallels the relentless clinical progression seen in these disorders. Mathematical models suggest that the same basic cellular mechanisms are responsible for the amplification of mutant mtDNA in ageing, in tumours, and in mtDNA disease. The accumulation of cells that contain high levels of mutant mtDNA may be an inevitable result of the normal mechanisms that maintain cellular concentrations of mtDNA.     

Two cases of hantavirus pulmonary syndrome in Randolph County, West Virginia: a coincidence of time and place?

Hantavirus pulmonary syndrome (HPS) is caused by an infection with viruses of the genus Hantavirus in the western hemisphere. Rodent hosts of hantaviruses are present throughout the United States. In July 2004, two HPS case-patients were identified in Randolph County, WV: a wildlife science graduate student working locally and a Randolph County resident. We interviewed family members and colleagues, reviewed medical records, and conducted environmental studies at likely exposure sites. Small mammals were trapped, and blood, urine, and tissue samples were submitted to the Centers for Disease Control and Prevention for laboratory analyses. These analyses confirmed that both patients were infected with Monongahela virus, a Sin Nombre hantavirus variant hosted by the Cloudland deer mouse, Peromyscus maniculatus nubiterrae. Other than one retrospectively diagnosed case in 1981, these are the first HPS cases reported in West Virginia. These cases emphasize the need to educate the public throughout the United States regarding risks and prevention measures for hantavirus infection.     

Different Trends of MRSA and VRE in a German Hospital, 1999–2005

Abstract Some of the clinically most menacing nosocomial pathogens are Methicillin-resistent Staphylococcus aureus (MRSA) and Vancomycin-resistent Enterococcus (VRE). During the last years both pathogens showed dramatic increases in colonization and infection rates in Germany. This study covers all patients positively tested for MRSA and VRE in a German University Hospital from 1999–2005. About 1,179 MRSA cases and 116 VRE cases have been reported. VRE was significantly associated with less infection, female gender, more death and higher nosocomial acquisition than MRSA. While MRSA rates increased impressively from 1999 to 2005 VRE rates decreased clearly. Assuming that compliance with hygienic measures is similar in dealing with MRSA and VRE it is quite unclear why these two major pathogens differ so much in their trends. One possibility is that the MRSA problem has been caused by an increasing share of nonnosocomially acquired MRSA.     

Functional analyses of variants reveal a significant role for dominant negative and common alleles in oligogenic Bardet–Biedl syndrome

Technological advances hold the promise of rapidly catalyzing the discovery of pathogenic variants for genetic disease. However, this possibility is tempered by limitations in interpreting the functional consequences of genetic variation at candidate loci. Here, we present a systematic approach, grounded on physiologically relevant assays, to evaluate the mutational content (125 alleles) of the 14 genes associated with Bardet–Biedl syndrome (BBS). A combination of in vivo assays with subsequent in vitro validation suggests that a significant fraction of BBS-associated mutations have a dominant-negative mode of action. Moreover, we find that a subset of common alleles, previously considered to be benign, are, in fact, detrimental to protein function and can interact with strong rare alleles to modulate disease presentation. These data represent a comprehensive evaluation of genetic load in a multilocus disease. Importantly, superimposition of these results to human genetics data suggests a previously underappreciated complexity in disease architecture that might be shared among diverse clinical phenotypes.     

An analysis of reported cases of leishmaniasis in the southern Ecuadorian Amazon region, 1986–2012

An analysis of reported cases of cutaneous leishmaniasis (CL) was performed using the data registered in the southern Ecuadorian Amazon region during 27 years from 1986 to 2012. The cases/subjects with both the suspected CL lesions and the amastigote-positive results were recruited for the analysis. The yearly occurrence of cases showed a markedly higher number during the six years, 1988 and 1993. After 1994 when the insecticide spraying campaign using helicopter in 1993–1994, the number dropped remarkably. Then, the yearly occurrence gradually fluctuated from 101 cases in 1996 to 11 in 2009, maintaining a low number of cases after the campaign. The monthly occurrence of cases showed a markedly high number during March and August, suggesting a correlation to the rainy season (months) in the areas. A statistical significance was found between the monthly average number of the CL case and the average precipitation (p = 0.01474). It was suggested that the time of transmission of CL would depend on the rainy seasons at each endemic area of Ecuador, which has a diverse climatic feature depending on the geographic regions. Such information at given leishmaniasis-endemic areas of Ecuador would be important for the future planning of the disease control. Molecular analysis and characterization of clinical samples revealed the presence of Leishmania (Viannia) braziliensis.     

What is a common factor in different areas?: The case of depression among caregivers of the frail elderly in Sapporo and Kochi,Japan

Aim: Depression affecting caregivers is a risk factor for discontinuing at‐home care. The present cross‐sectional study was conducted to evaluate factors related to depression among family caregivers. Methods: A cross‐sectional study was conducted to evaluate factors related to depression among family caregivers of the frail elderly. The study included caregivers whose relatives received periodic visits from a nurse from one of seven Sapporo‐based home‐visiting nursing service stations in October 2008 or from one of nine Kochi‐based home‐visiting nursing service stations between June 2009 and March 2010. Caregivers were asked to answer a self‐administered questionnaire about various factors that might affect their depression and to complete a Center for Epidemiologic Studies Depression Scale evaluation. We analyzed 127 pairs of responses in total. Results: After we adjusted the results for the caregivers' gender and age, the factors that decreased the risk of depression in the Sapporo group related to relieving the stress that results from being a caregiver (OR = 0.12, 95%CI = [0.03, 0.42]) and the ability to independently pay more than ¥10 000 for part of care service costs (OR = 0.17, 95%CI = [0.05, 0.58]). In contrast, feeling ill was a factor that increased caregivers' risk of depression in the Kochi group (OR = 4.23, 95%CI = [1.29, 13.9]), but not in Sapporo group (OR = 2.53, 95%CI = [0.91, 7.08]). Caregivers in the Sapporo group were more likely to feel ill (P < 0.01) than their counterparts in Kochi. Conclusion: The Japanese government should take measures to reduce caregivers' depression. Otherwise family members will increasingly discontinue to provide at‐home care. Geriatr Gerontol Int 2012; 12: 230–237.     

Colloquium paper: how many tree species are there in the Amazon and how many of them will go extinct?

New roads, agricultural projects, logging, and mining are claiming an ever greater area of once-pristine Amazonian forest. The Millennium Ecosystems Assessment (MA) forecasts the extinction of a large fraction of Amazonian tree species based on projected loss of forest cover over the next several decades. How accurate are these estimates of extinction rates? We use neutral theory to estimate the number, relative abundance, and range size of tree species in the Amazon metacommunity and estimate likely tree-species extinctions under published optimistic and nonoptimistic Amazon scenarios. We estimate that the Brazilian portion of the Amazon Basin has (or had) 11,210 tree species that reach sizes >10 cm DBH (stem diameter at breast height). Of these, 3,248 species have population sizes >1 million individuals, and, ignoring possible climate-change effects, almost all of these common species persist under both optimistic and nonoptimistic scenarios. At the rare end of the abundance spectrum, however, neutral theory predicts the existence of approximately 5,308 species with <10,000 individuals each that are expected to suffer nearly a 50% extinction rate under the nonoptimistic deforestation scenario and an approximately 37% loss rate even under the optimistic scenario. Most of these species have small range sizes and are highly vulnerable to local habitat loss. In ensembles of 100 stochastic simulations, we found mean total extinction rates of 20% and 33% of tree species in the Brazilian Amazon under the optimistic and nonoptimistic scenarios, respectively.     

Henoch–Schönlein purpura in childhood: treatment and prognosis. Analysis of 425 cases over a 5-year period

The objective of this study was to identify the most effective treatment by evaluating the different therapies used to treat mild, moderate, and severe Henoch–Schönlein purpura (HSP) patients. We performed a retrospective study of children discharged with a diagnosis of HSP. The study group consisted of 425 children divided into mild, moderate, and severe condition groups. Different therapeutic protocols of hydrocortisone sodium succinate (HCSS) therapy, methylprednisolone (MP) pulse therapy, and MP combination with tripterygium glycoside (TG) therapy were used to treat the different groups. The evaluation of curative effect was performed. After 4 weeks, all patients with no obvious recovery were treated by strengthening the different treatment intervention. The remission time of skin, joint, and gastrointestinal manifestations was evaluated, and the results of the follow-up were analyzed (remission time of proteinuria, relapse, and side effects of therapy). After 4 weeks, in the mild group, the difference of the curative effect between HCSS and MP therapy was not statistically significant. Moderate HSP patients were more likely to respond to MP therapy than HCSS therapy (P?P?P?P?P?>?0.05). Our study has demonstrated a superior effect for HCSS therapy in patients with mild HSP disease, for MP therapy in patients with moderate disease, and for MP combined with TG therapy in patients with severe disease. MP therapy administered initially reduces the duration of urinary protein abnormality. The therapeutic protocols did not increase the risk of relapse and were safe.     

What do the needles, syringes, lancets and reagent strips of diabetic patients become in the absence of a common attitude? About 1070 questionnaires in diabetic clinics

The aim was to investigate the fate of injection and monitoring material after its use by diabetic patients in different countries (France, Belgium, Luxemburg, Switzeland and Tunisia). Some suitable containers are available for disposal but little is known about the attitudes of patients and physicians to them. 1 070 questionnaires were completed by patients (age: 50 +/- 18 years; diabetes duration: 15 +/- 11 years; 2.8 +/- 1.1 injections per day) visiting 109 doctors. Injections were done at home (72.6%), or both at home and at work (26.6%). At home: needles, syringes, lancets and reagent strips were thrown directly into the bin in 46.9%, 49.9%, 52.2% and 67.6% of cases, respectively; and in a closed plastic bottle in 29. 6%, 28.5%, 28.9% and 19.9% of cases, respectively. Specific containers were used in 8.6% and 6.3% of cases for needles and syringes, respectively. 62% of the bottles and containers were thrown directly into the bin, whereas 15.5% were returned to a pharmacy (4.5% taken to hospitals, 2.9% were burned). At work: 63% of the patients brought their needles and syringes home for disposal, 6.9% kept suitable containers at work and 30% threw their materials directly into local bins. We conclude that awareness should be increased and the organization of the collection of used material improved.     

Trends of HIV Risk Behaviors in a Cohort of Injecting Drug Users and Their Sex Partners in Miami,Florida, 1988–1998

A cohort of 111 injection drug users (IDUs) and their sex partners was assessed in 1988 concerning risk behaviors for HIV and knowledge of HIV/AIDS. Ten years later, in 1998, the cohort was reassessed using the same instrument. All who were HIV negative in 1988 were retested by blood draw for antibodies to HIV. A paired analysis was utilized to determine individual changes in risk behaviors for three serostatus groups—those who remained HIV negative (long-term HIV negatives), seroconverters, and those positive in 1988 (long-term HIV positives). Incidence was twice as high for sex partners (37.5%) as for IDUs (18.0%). Drug and needle use risk behaviors, except crack use, showed decreases; sexual risk behaviors were less amenable to change. Knowledge significantly increased among the long-term HIV negatives and seroconverters but not among those HIV positive in 1988. This analysis demonstrates the need for continued intervention among IDUs and their sex partners.     

Effects of agomelatine in a murine model of obsessive–compulsive disorder: Interaction with meta-chlorophenylpiperazine,bicuculline, and diazepam

The anticompulsive potential of agomelatine, a potent MT_1/2 receptor agonist, and its combined effect with m-chlorophenylpiperazine hydrochloride (mCPP), bicuculline, and diazepam, were investigated in male C57BLJ/6 mice using marble-burying behavior (MBB) test. Acute administration of agomelatine (30–40 mg/kg, intraperitoneal (i.p.)) significantly inhibited the MBB in mice without influencing their locomotor activity. Further, chronic (28 days) administration of lower doses of agomelatine (10 and 20 mg/kg, i.p.) dose-dependently reduced the MBB without influencing their locomotor activity. Interaction studies revealed that pretreatment with mCPP (0.5 mg/kg, i.p.), a serotonin 5HT_2C agonist, partially attenuated the anticompulsive effect of agomelatine (30 mg/kg). Further, a GABA_A receptor agonist (diazepam, 1.25 mg/kg, i.p.) and antagonist (bicuculline, 1 mg/kg, i.p.) had no influence on the effects of agomelatine on MBB and locomotor activity. The doses of modulators were selected on the basis of dose-response studies. The results indicate that agomelatine has a potent anticompulsive effect that can be attributed to 5HT_2C antagonism and MT_1/2 agonism, and is certainly not mediated via its effects on the GABAergic system. Thus, the study adds to the growing literature on the psychopharmacological effects of agomelatine, and warrants further exploration in multiple paradigms.