Species of Metarhizium anisopliae complex implicated in human infections: retrospective sequencing study

OBJECTIVES

Fungi belonging to the Metarhizium anisopliae complex comprise ubiquitous arthropod pathogenic moulds used as mycopesticides. Rare cases of human infections due to M. anisopliae have been reported. We hypothesize misidentifications of fungal strains implicated in these cases or used in mycopesticides.

METHODS

A review of the literature was conducted to identify previously published cases. We collected some of these previous described strains and reported new cases, and a French mycopesticide containing M. anisopliae. All identifications were performed based on elongation factor-1α gene sequencing.

RESULTS

We report eight new cases of Metarhizium infection in humans (three from France and five from Australia). The strains isolated from these cases, and three others from already published cases and reported as M. anisopliae, were molecularly identified based on elongation factor-1α (Ef1-α) gene sequencing as follows: Metarhizium robertsii (six), Metarhizium guizhouense (three), Metarhizium brunneum (one) and Metarhizium pingshaense (one).

CONCLUSIONS

In this study, we report new human cases of Metarhizium infections, and, based on Ef-1α gene sequencing, we demonstrate the misidentification of species in case reports. We also correct the species identification of a strain reported as M. anisopliae used in a commercially available mycopesticide. According to our results, none of the strains from the human infection reports reviewed belongs to the species M. anisopliae.

Maximum potential cost-savings attributable to generic substitution of antipsychotics 2008 to 2013

Background: Schizophrenia is a costly illness to treat, especially during a time of escalating medicine inflation costs, putting a large economic strain on patients, their families and the community. Treatment, however, can become more affordable through generic substitution.Objective: To determine the maximum potential cost-saving through generic substitution for both originator and more expensive generic items while observing the prescribing patterns of antipsychotics.Method: Antipsychotic medicine usage was analysed retrospectively during the study period 2008 to 2013 using data obtained from a nationally representative Pharmaceutical Benefit Management Company. The study population consisted of 4410 patients with ICD-10 codes (F20-F20.9) who had paid claims for an antipsychotic reimbursed from their prescribed minimum benefits. Active ingredients were identified using the MIMS classification system. Maximum potential cost savings were determined by substituting all originator and more expensive generic antipsychotic items with the cost of the least expensive generic antipsychotic item available.Results: Through generic substitution, a total potential cost-saving of ZAR4 642 685.45 could be possible from 2008 to 2013. Average cost per items increased from ZAR600.53 ± ZAR435.00 (median ZAR 539.82) in 2008 to ZAR1 196.59 ± ZAR 942.16 (median ZAR 940.72) in 2013 and had a significant effect on patients' contribution, which increased with 726.94% from 2005 to 2008. Psychiatrists prescribed the majority of antipsychotics. Although generic items claimed increased by 60.31% during the study period, psychiatrist still favoured non-generic prescribing (40.63%).Conclusions: Potential economic benefits can be generated with generic substitution.

[Intraocular lymphoma associated with primary malignant lymphoma of the central nervous system: Seven-year experience of a tertiary center]

INTRODUCTION

Primary intraocular lymphoma (PIOL), associated with primary central nervous system lymphoma (PCNSL), is a rare malignancy disease. By way of a seven-year experience of a tertiary center, we discuss the presentation and we review the diagnostic and therapeutic modalities.

OBSERVATIONS

We report six cases of PIOL associated with PCNSL. For all patients, the clinical presentation was a vitreoretinal syndrome. The diagnosis was histologically confirmed by vitreal sample or brain biopsy. Five patients developed a diffuse large B-cell lymphoma. Only one patient developed a T-cell lymphoma. The treatment consisted of conformational radiation therapy, systemic chemotherapy and intravitreal injections of methotrexate. The median survival after the diagnosis was 24 months.

DISCUSSION

PIOL, associated with PCNSL, is the most common type of ocular lymphoma. In most cases, ocular manifestations inaugurate the disease. PIOL is often fatal because of ultimate central nervous system presentation. The role of the ophthalmologist consists in early diagnosis. Typical clinical findings include vitroretinal tumor syndrome but can mascarade other eye pathologies. Diagnosis requires histology. The majority of PIOL is diffused large B-cell lymphoma. Decisions are made through multidisciplinary consultation. PIOL exhibits high responsiveness to methotrexate.

CONCLUSION

Through a literature review and many illustrations, we discuss epidemiological, clinical, histological, radiological and treatment characteristics of PIOL associated with PCNSL.

[Combined hamartoma of the retinal pigment epithelium and retina: case report]

We report the case of a 19-year-old woman with a combined hamartoma of the retinal pigment epithelium and retina incidentally discovered during her first eye exam. By way of this case, we describe and illustrate the epidemiological and clinical characteristics of the condition and its potential complications.

Effects of heat exposure on Akt/S6K1 signaling and expression of genes related to protein and energy metabolism in chicken (Gallus gallus) pectoralis major muscle

In order to improve understanding of the heat-induced changes in muscle growth, we determined the expression of genes related to protein and energy metabolism in the pectoralis major muscle of chickens. We also explored the protein kinase B (PKB also called Akt)/p70 S6 kinase (S6K1)/S6 pathway that mediates anabolic signals thereby regulating metabolism and hypertrophic/atrophic balance. Four-week-old chickens were exposed to 32 or 22 degrees C for 1 week. Chickens from both groups were then fasted for 16 h or left fed, and submitted to an oral administration of glucose-arginine to induce an anabolic response (30-min treatment) or left untreated. High ambient temperature and the associated decrease in feed intake modified the expression of certain energy-related genes (e.g. -40% for PGC-1alpha) and protein metabolism (e.g. about +80% for atrogin-1), but the expression of several muscle metabolism-related genes considered here was unchanged. The capacity for muscle protein synthesis, i.e. RNA/protein ratio, was reduced in warm conditions (approximately -20%). Slightly lower activation of S6 induced by glucose-arginine treatment was found at 32 degrees C compared to 22 degrees C, which might indicate somewhat lower efficiency of mRNA translation. Analysis of glucose/insulin balance suggested changes in glucose metabolism under heat exposure. However, this remains to be characterized.

The beta-adrenergic system is involved in the regulation of the expression of avian uncoupling protein in the chicken

Avian uncoupling protein (avUCP) is orthologous to UCP3, which is suggested to be involved in fatty acid metabolism and to limit the mitochondrial production of reactive oxygen species in mammals. In the chicken, the role and regulation of avUCP remain to be clarified. The aim of this study was to explore the control of avUCP expression by the beta-adrenergic system, known to be involved in avian thermoregulation and lipid utilization, and in UCP expression in mammals. Therefore, we measured the expression of avUCP mRNA and protein in the Pectoralis major muscle of chickens injected with the beta(2) agonist isoproterenol, and we investigated the potential pathways involved in the regulation of avUCP mRNA expression. Avian UCP mRNA expression was increased 7-fold 4h after isoproterenol injection, leading to a tendency to a 40% increase in avUCP protein 24h post-injection. This increase was preceded, 30 min after isoproterenol injection, by changes in the chicken thyroid status and in the muscular expression of PPARalpha, PPARbeta/delta, and PPARgamma coactivator-1alpha (PGC-1alpha). Moreover, the analysis of the avUCP promoter sequence suggested potential binding sites for PPARs and for thyroid hormone receptors. We also detected the activation of AMP-activated protein kinase, which has recently been reported to be involved in UCP3 regulation in mammals. This study presents for the first time evidence of beta-adrenergic control on avUCP messenger expression in chicken muscle and suggests the potential involvement of AMPK and several transcription factors in this regulation.

Variation in enrollment of colorectal cancer patients in clinical trials

e15094

Background: Correct estimation of patient enrollment is an important success factor for planning clinical studies including studies for metastatic colorectal cancer (CRC). Methods: We reviewed all CRC studies published in the Journal of Clinical Oncology and Annals of Oncology between 01/2007 and 10/01/2008. 43 studies were found and the following data were collected from 39 studies: indication, phase, number of sites, number of patients enrolled, mean patient age, recruitment time, sponsor (Industry, NIH, Organization, University), region, line of treatment and type of drug (6 categories). 4 studies were omitted from analysis as recruitment data were largely missing. Our analysis is based on a literature review as information from unpublished trials is unavailable. This implies some limitations regarding the data interpretation. Results: An average enrollment of 0.92 Patient/Site/Month (range 0.10–7.38) was observed for these trials. The highest recruitment efficacy with a median of 4.11 Pt/S/M (range 1.81–7.38) was found in 5 single institution phase II trials. For multi-center phase II and III studies the median enrollment was 1.82 and 0.32 Pt/S/M respectively, with significant higher recruitment in phase II studies. The highest enrollment rate was observed for studies located in Europe or in USA (0.77 and 2.21 Pt/S/M respectively, p=0.03). No correlation was seen with the mechanism of action (targeted drug vs. chemotherapy), sponsor (NIH vs. Industry vs. IIT), line of treatment (first line vs. 2nd and subsequent line). For phase I recruitment analysis we retrieved 2 studies that investigated novel agents in solid tumor patients including advanced or metastatic colorectal cancer patients with a median recruitment of 0.46 Pt/S/M. For phase Ib and I/II recruitment analysis 5 studies were found with a median recruitment of 0.78 Pt/S/M. Conclusions: Single institution phase II clinical trials on novel agents with high potential to change future treatment standard demonstrate almost a tenfold higher than average recruitment rate for multi-center trials (0.45 Pt/S/M). Despite some limitations in the interpretation of results our analysis provides important information to support estimation of patient recruitment in future clinical trials for colorectal cancer.

No significant financial relationships to disclose.

Computed tomography appearances in paediatric tuberous sclerosis

No abstract available.

Identification by mass spectrometry of two-dimensional gel electrophoresis-separated proteins extracted from lager brewing yeast

As two-dimensional (2-D) electrophoresis allows the separation of several hundred proteins in a single gel, this technique has become an important tool for proteome studies and for investigating the cellular physiology. In order to take advantage of information provided by the comparison of proteome pictures, the mass spectrometry technique is the way chosen for a rapid and an accurate identification of proteins of interest. Unfortunately, in the case of industrial yeasts, due to the high level of complexity of their genome, the whole DNA sequence is not yet available and all encoded protein sequences are still unknown. Nevertheless, this study presents here 30 lager brewing yeast proteins newly identified with matrix assisted laser desorption/ionization-time of flight (MALDI-TOF), tandem mass spectrometry (MS/MS) and database searching against the protein sequences of Saccharomyces cerevisiae. The identified proteins of the industrial strain correspond to proteins which do not comigrate with known proteins of S. cerevisiae separated on 2-D gels. This study presents an application of the MS technique for the identification of industrial yeast proteins which are only homologous to the corresponding S. cerevisiae proteins.

Computed tomography features of venous sinus thrombosis and infarction in children

No abstract available.

Two-dimensional gel analysis of the proteome of lager brewing yeasts

Modern lager brewing yeasts used in beer production are hybrid strains consisting of at least two different genomes. To obtain information on the identity of the parental strains that gave rise to industrial lager yeasts, we used two-dimensional (2-D) gel electrophoresis and analysed the proteomes of different Saccharomyces species isolated from breweries. We found that the proteome of lager brewing yeasts and of the type strains of S. carlsbergensis, S. monacensis and S. pastorianus can be interpreted as the superimposition of two elementary patterns. One originates from proteins encoded by a S. cerevisiae-like genome. The other corresponds to a divergent Saccharomyces species whose best representative is a particular S. pastorianus strain, NRRL Y-1551. A map of industrial lager brewing yeasts has been established, with the individual origin of proteins and with identification of protein spots by comparison to known S. cerevisiae proteins. This 2-D map can be accessed on the Lager Brewing Yeast Protein Map server through the World Wide Web. This study provides the first example of the use of proteome analysis for investigating taxonomic relationships between divergent yeast species.

Two-dimensional gel protein database of Saccharomyces cerevisiae

With the systematic sequencing of the yeast genome, yeast biology has entered a new era where novel challenges have to be faced. One challenge is the identification of the function of the several hundred novel genes discovered by genome sequencing. Another is to understand how all yeast genes act in concert to ensure and maintain cell organization. Two-dimensional (2-D) gel electrophoresis is the technique of choice to take up these challenges because it provides the opportunity of obtaining an overall view of genome expression. In prospect of these studies we have undertaken the construction of a yeast 2-D gel protein database that contains information on polypeptides of the yeast protein map. In this paper we report the information presently contained in this database. The reported information includes the identification of 250 protein spots and the characterization of polypeptides corresponding to N-terminal acetylated proteins, mitochondrial proteins, glucose-repressed proteins, heat shock induced proteins and proteins encoded by intron-containing genes. In all, 600 spots are annotated. These data can be accessed on the Yeast Protein Map server through the World Wide Web network.

Development of screening methods for detection of carbohydrate-binding proteins by use of soluble glycosylated polyacrylamide-based copolymers

Mammalian endogenous carbohydrate-binding proteins (lectins) play fundamental roles in a variety of mechanisms of interactions both at the molecular and cellular levels. We have investigated the binding of one of them (human brain lectin) to soluble acrylamide copolymerized with derivatives of either lactose (O-beta-lactosyloxyallylallylaminoacrylamide copolymer) or D-mannose (D-alpha-mannosyloxyallylallylaminoacrylamide copolymer) in direct enzyme affinoassays, in an attempt to develop simple procedures for detection and estimation of its carbohydrate-binding activity. Biotinylated plant lectins were utilized as reference standards. Affinoassays employed the polymer dotted on nitrocellulose and the polymer coated on microtiter plates as well as detection of bound biotinylated lectin by streptavidin/horseradish peroxidase reagent. Both assays provided reproducible binding, inhibitable by specific sugars. The microtiter plate assay is well suited to sensitive detection of the negative endogenous lectin by competition with biotinylated brain lectin. We conclude that the use of derivatized acrylamide in dotting and microtiter plate assays may prove practical for detection of endogenous lectins and that such polymers may serve as model substances in the study of biological partners of these carbohydrate-binding proteins.

Human brain lectin: a soluble lectin that binds actin

A biotinylated probe was used for detection of endogenous ligands of a human brain lectin on blotted human brain soluble proteins. Of the various proteins from brain extract resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, five reacted with the biotinylated probe. After elimination of saccharidic moieties by periodic treatment of the same extract, a single band with Mr approximately 43,000 was recognized by the lectin. This band was identified as actin using an anti-actin antibody. These results were confirmed by binding of biotinylated lectin to purified actin.

Human brain lectin immunoreactive material in cerebrospinal fluids determined by enzyme immunoassay (EIA)

A sensitive enzyme immunoassay (EIA) micromethod is described which can measure levels of a 14 kDa human brain lectin (HBL) in the cerebrospinal fluid (CSF) of patients submitted to CSF examination. The assay is based on the use of a polyclonal antibody to HBL and the simultaneous application of biotinylated and unlabeled HBL. Biotin was then reacted with a streptavidin-peroxidase (Strep-HRP) conjugate and the bound enzyme quantified with the substrate orthophenylenediamine (OPD). The assay requires only 50 microliters of CSF and is very sensitive: as little as 6 ng/ml of HBL 14 can be detected. In a blind-test screening, the mean (+/- SEM) concentration of the HBL immunoreactive material (HIM) in CSF was determined to be 72.4 +/- 6.6 ng/ml. Our results indicate that EIA measurement of HIM levels in the CSF may find useful applications in elucidating the involvement of HBL in the physiopathology of human nervous system (NS).

Biotinylated derivative of a human brain lectin: synthesis and use in affinoblotting for endogenous ligand studies

Coupling of biotin to an endogenous lectin yields a probe which can be used for selective nonradioactive detection of complementary endogenous ligands. To exemplify practical applications of this type of compounds, we have synthesized and characterized a biotinylated derivative of a beta-galactoside-specific human brain lectin. Proteins which bind this lectin can be located on nitrocellulose sheets after electrophoretic transfer from gradient polyacrylamide gels, by sequential incubation with biotinylated probes and streptavidin-peroxidase, with visualization by an insoluble reaction product (affinoblotting). Biotinylated galactoside-binding plant lectins were used in the same way to visualize human brain glycoproteins, and their binding specificity was compared with that of human brain lectin. The results obtained by means of these different probes showed the usefulness of the endogenous lectin derivative to actually identify its endogenous partners. Thus this approach may find extended applications in the study of biological activities of vertebrate lectins in homologous systems, i.e., with lectins and ligands coming from the same tissue origin.

Soluble galactoside-binding vertebrate lectins: a protein family with common properties

1. Soluble galactoside-binding lectins could play a key role in vertebrates by specifical binding to complementary glycoconjugates. 2. Their expression and localization are developmentally regulated. 3. They constitute a large family of structurally related proteins which contain a series of conserved aminoacids. 4. Their functional role could vary from an organ to another, and the same lectin may probably mediate several biological activities.

Soluble heparin-binding lectins from human brain: purification, specificity and relationship to an heparin-binding growth factor

1. An heparin-binding lectin activity was detected in soluble extracts of human brain. Three polypeptide chains were purified by affinity chromatography on heparin-Sepharose. Their Mrs estimated by polyacrylamide gel electrophoresis were 13,000, 14,500 and 16,000. 2. Several glycosaminoglycans were potent inhibitors of their hemagglutination activity. 3. From the pool of purified lectins three peaks were separated by reversed-phase high-performance liquid chromatography. They were indistinguishable by activity criteria (hemagglutination, stimulation of endothelial cell growth), and immunological relationship was found between one of them and acidic fibroblast growth factor (aFGF).

Purification and characterization of a galactoside-binding lectin from human brain

A beta-galactoside-binding hemagglutinin was detected in soluble extracts of human brain. This soluble lectin was purified to homogeneity by affinity column chromatography on lactose coupled to divinylsulfone-activated agarose. The purified lectin had an isoelectric point of 3.9 and its subunit molecular mass estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate was 14,500. Human brain lectin was not a glycoprotein and its amino acid composition was characterized by a high content of serine, glutamic acid, and glycine, and a low content of methionine and cysteine. The most potent saccharide inhibitors tested were thiodigalactoside, lactose, and p-nitrophenyl-beta-D-galactoside. An antibody was raised to the pure lectin. Immunological relationships were found between the brain lectin and several other soluble lectins of various vertebrate origins.

Immunohistochemical localization of a beta-galactoside-binding lectin in rat central nervous system. II. Light- and electron-microscopical studies in developing cerebellum

An endogenous brain lectin exhibiting beta-galactoside specificity (RBL-16) was localized during postnatal cerebellum development both at the light- and electron-microscopical level. The lectin was widely distributed in neurons, astroglial and perivascular cells. Its levels were nearly constant during development in the two latter cell types. The lectin was developmentally regulated with a transient accumulation in Purkinje dendritic spines between the 10th- and 13th day, then it decreased until adult age. From electron-microscopical observations, it could be concluded that, in Purkinje cells, the lectin remained in the intracellular compartment, in dendrites and cell bodies. It was never externalized in the region where synaptogenesis takes place. A role in the intracellular transport of molecules should be expected from such a localization. The lectin was also transiently found on the surface of postmitotic neuroblasts in the external germinative layer and on the parallel fibers of the upper part of the molecular layer. However, it was not expressed inside neuroblasts. This suggests that part of the lectin found on the surface of neuroblasts originates from heavily stained astrocytes which could secrete it. RBL-16 could be making bridges between neuroblasts in the premigratory zone and between growing axons. A role in transient neuroblast adhesion in the external germinative layer and in parallel fiber fasciculation is expected from such a localization.

Immunohistochemical localization of a beta-galactoside-binding lectin in rat central nervous system. I. Light- and electron-microscopical studies on developing cerebral cortex and corpus callosum

From a lectin isolated from human brain (HBL-14), that specifically binds beta-galactosides, a polyclonal antiserum was raised that also recognizes a similar rat brain lectin (RBL-16). These antibodies allowed the immunocytochemical localization of the lectin during rat brain development by optical and electron microscopy. The presence of RBL-16, first detected at embryonic day 15, was specially increased from postnatal day 1 to 10. Its level decreased thereafter but it could still be detected in adult rat brain. The lectin, predominantly neuronal until postnatal day 13, was also present in astrocytes and perivascular cells where no developmental regulation was observed in contrast to neurons. Electron microscopy showed that the lectin was transiently expressed in the axoplasm of almost all neurons in layer I around the birth date, after which it remained inside neurons, including cell bodies and dendrites, in all examined regions. The lectin was clearly localized in postsynaptic structures. This beta-galactoside-specific lectin may be involved in synaptogenesis and neurite fasciculation as well as in intracellular traffic as discussed.

Purification and some characteristics of a beta-galactoside binding soluble lectin from amphibian ovary

Soluble extracts of Bufo ovaries agglutinate sialidase-treated rabbit erythrocytes. Unlike other amphibian lectins this agglutination activity does not require the presence of calcium ions. It is specifically inhibited by D-galactose and its derivatives. Thiodi-D-galactoside is the most potent saccharide inhibitor followed by lactose and methyl-beta-D-galactoside, respectively. D-Fucose, D-glucose and D-mannose do not inhibit the activity at concentrations at or above 100 mM. The lectin has been purified 500-fold to apparent homogeneity from the ovaries by salt extraction and affinity chromatography on lactose-aminophenyl-agarose, with a yield of about 0.2%. The molecular mass determined by gel filtration under native conditions was 30 kDa; polyacrylamide gel electrophoresis in SDS gave a molecular mass of 15 kDa, suggesting that the lectin is a dimer. The lectin has an isoelectric point of 40 and contains a high proportion of acidic amino acids.

Brain lectin-mediated agglutinability of dissociated cells from embryonic and postnatal mouse brain

Brain extracts contain a soluble lectin which enables the agglutination of dissociated mouse brain cells via saccharidic receptors. The ability of the brain cells to be agglutinated depends on their stage of development in vivo. Furthermore, after birth, the mechanism of the lectin-promoted agglutination is complicated by the appearance of a self-aggregation of the dissociated cells. Lactose and galactosides are inhibitors of lectin-mediated agglutination as well as of the dissociated cells' self-aggregation.

Purification and characterization of a beta-galactoside-binding soluble lectin from rat and bovine brain

A beta-galactoside-binding activity has been detected in mammalian brain extracts using a hemagglutination test and a nerve cell aggregation assay. Inhibition studies suggested the involvement of lectin-carbohydrate interactions in these processes. In an attempt to explore further the biological role of brain lectins, the beta-galactoside-binding activity has been purified to apparent homogeneity from bovine and rat brain by salt extraction of the brain tissue and affinity chromatography on asialofetuin-agarose. The molecular weights determined by gel filtration, under native conditions on Ultrogel AcA-34, were 30,000 for the bovine brain lectin and 32,000 for the rat brain lectin; polyacrylamide gel electrophoresis in SDS gave molecular weights of 15,000 and 16,000, respectively, suggesting that the two brain lectins are dimers. Both lectins have an isoelectric point of 3.9. Amino acid composition data indicate that both lectins contain high proportions of glycine and acidic amino acids. The lectins are specific for beta-D-galactosides and related sugars and the configuration of carbon atoms 1, 2 and 4 seems of primary importance. Moreover, the nerve cell aggregation-promoting activity of the purified lectin is 300-fold that of the crude extracts.

Investigation on the occurrence of soluble lectins in mammalian nervous tissue extracts

Five brain or retina crude extracts obtained from adult mammalians and nine fractions of brain extracts prepared by chromatography were screened for their lectin activities. All crude extracts and several fractions contained agglutinins reacting with neuraminidase-treated rabbit red blood cells. Hemagglutination activity varied widely with the method of preparation of the extracts. Hemagglutination inhibition tests were carried out to look for possible differences in the specificities of the agglutinins. All were found to be D-galactosyl specific. Each crude extract was found to contain a second lectin activity, which was detected using ethanol-treated rabbit erythrocytes known to react with heparin-binding lectins. Hemagglutination and inhibition studies showed that they completely differ from the galactoside-binding lectins detected previously. The possible functions of these lectins are discussed.

Development of immunologically identified brain cells in culture: quantitative aspects

Mechanically dissociated brain cells of 14 and 18-day-old mouse embryos and of mouse neonates were cultured for 3 weeks. Neurons, oligodendrocytes and astrocytes were identified at the 7th, 14th and 21st day in vitro by staining the cultures using the indirect immunoperoxidase technique with antisera directed against neuron specific enolase, galactocerebroside, myelin basic protein and glial fibrillary acidic protein. The number of neurons and oligodendrocytes was higher in embryonic cultures than in neonate cultures. The expression of some antigens was also different in the two types of culture. Our results indicate that the development of brain cells in mechanically dissociated brain cell cultures depends on the age of the animal at the time of plating.

Proliferative activity and characteristics of immunocytochemically identified oligodendrocytes in embryonic mouse brain cell cultures

Dissociated brain cell cultures of 14-day-old mouse embryos (E 14) were used for studying, during development, the proliferative activity of oligodendrocytes which express myelin basic protein (MBP) and galactocerebroside (GC). This was done using a combination of 3H-Thymidine autoradiography and immunoperoxidase or immunofluorescence. Quantitative estimates of labeled cells were made using a Leitz Texture Analysis System (T.A.S.) coupled to a P.D.P. 11-34 minicomputer. Results showed that differentiated oligodendrocytes, which express both MBP and GC, are able to proliferate. According to the intensity of the immunostaining, strong MBP positive and weak MBP positive oligodendrocytes were observed. Only the weak MBP positive cells incorporated 3H-Thymidine. The highest percentage (22.5%) of 3H-Thymidine labeled oligodendrocytes was observed at day 6 in vitro, and was reduced by half at day 9 to 13. Oligodendrocytes which have undergone a first division are still able to proliferate.

Accelerated differentiation of oligodendrocytes in neuronal-rich embryonic mouse brain cell cultures

The expression of two oligodendroglial markers, galactocerebroside (GC) and myelin basic protein (MBP), was studied in brain cell cultures (BCC) from 14-day-old mouse embryos by immunocytochemical methods. The presence of neurons and astrocytes was also investigated. Results show that oligodendrocytes simultaneously express both GC and MBP already at 7 days in vitro. These cultures are rich in neurons, and the astrocyte layer is also well represented. A comparison is made between these data and those previously obtained by the use of newborn mouse brain cell cultures, which are very poor in neurons. The differentiation of oligodendrocytes, as reflected in the expression of MBP, is accelerated in embryonic mouse BCC when compared to neonatal mouse BCC. We therefore speculate that neurons are involved in the enhancement of the ability of oligodendrocytes to express myelin related components in culture.

A standardized automatic procedure to evaluate cell numbers in low cell density tissues by image analysis: application to the Staggerer mutant mouse cerebellum

To obtain a reliable and fast quantification in low cell density tissues, we have developed a standardized procedure based on image analysis. The successive steps of quantification, starting with the necessary histological procedure and ending with the desired quantitative parameters, are described. Excepting the histological procedure, we have attempted to automate all the subsequent steps of the experiment, especially the acquisition of the data by an image analyser TAS (Leitz), and the storage and the analysis of these data by a PDP 11-34 computer. The final parameters calculated by such a method are the total number of cells and the cell density within the organ under study, either for all the cells, or for different cellular categories. This procedure has been applied to the quantitative study of cerebellar cells of an adult Staggerer mutant mouse and the results obtained are presented.