Therapy of Castleman's disease with siltuximab - case report and review of literature

BACKGROUND

Idiopathic multicentric Castleman disease (iMCD) is characterized by constitutional symptoms, enlarged lymph nodes and laboratory test abnormalities, which are primarily related to the overproduction of interleukin-6 (IL-6). This form (iMCD) was treated earlier with cytostatics used for lymphoma, later with bio-logic therapy as rituximab, immunodulatory drugs and proteasome inhibitors, and in the last years with an anti-IL-6 antibody, siltuximab. Siltuximab is a human-mouse chimeric immunoglobulin G1k monoclonal antibody against human IL-6 approved in the European Union for the treatment of iMCD. In view of the limited treatment options for iMCD, this case report aimed to evaluate the efficacy and safety of siltuximab in the management of this condition.

CASE

We describe a young woman with iMCD diagnosed at the age of 25 years. For first line treatment, rituximab and dexamethasone were used without any cytostatic because the patient wished to give birth to a healthy child in the future. However, the response after this first line therapy was short. In addition, after 3 years from the start of rituximab + dexamethasone therapy, it was necessary to administer treatment for the relapse of iMCD. We decided for siltuximab in this young woman, still aged < 30 years, and started administration of siltuximab in 3-week intervals.

RESULTS

After administration of first two infusions of siltuximab, all inflammatory markers returned to normal value. Moreover, serum hemoglobin and albumin levels as well as C-reactive protein normalized after the first two administrations of siltuximab. The clinical response continue, siltuximab is still administered in 3-week intervals. PET/CT with fluorodeoxyglucose confirmed a very good anatomic and metabolic response to the treatment. Siltuximab demonstrated a favorable safety profile, and the prolonged treatment was well tolerated.

CONCLUSION

This result is encouraging and demonstrates the potential of siltuximab as treatment of CD. As earlier published, this case confirms that significantly elevated inflammatory markers in a patient with CD predict a good response to siltuximab.

Environmental margin and island evolution in Middle Eastern populations of the Egyptian fruit bat

Here, we present a study of the population genetic architecture and microevolution of the Egyptian fruit bat (Rousettus aegyptiacus) at the environmental margins in the Middle East using mitochondrial sequences and nuclear microsatellites. In contrast to the rather homogenous population structure typical of cave-dwelling bats in climax tropical ecosystems, a relatively pronounced isolation by distance and population diversification was observed. The evolution of this pattern could be ascribed to the complicated demographic history at higher latitudes related to the range margin fragmentation and complex geomorphology of the studied area. Lineages from East Africa and Arabia show divergent positions. Within the northwestern unit, the most marked pattern of the microsatellite data set is connected with insularity, as demonstrated by the separate status of populations from Saharan oases and Cyprus. These demes also exhibit a reduction in genetic variability, which is presumably connected with founder effects, drift and other potential factors related to island evolution as site-specific selection. Genetic clustering indicates a semipermeability of the desert barriers in the Sahara and Arabian Peninsula and a corridor role of the Nile Valley. The results emphasize the role of the island environment in restricting the gene flow in megabats, which is also corroborated by biogeographic patterns within the family, and suggests the possibility of nascent island speciation on Cyprus. Demographic analyses suggest that the colonization of the region was connected to the spread of agricultural plants; therefore, the peripatric processes described above might be because of or strengthened by anthropogenic changes in the environment.

[Comparison of laparotomic and laparoscopic techniques for implantation of the peritoneal part of the shunt in the treatment of hydrocephalus]

INTRODUCTION

Implantation of a ventriculoperitoneal shunt is a standard procedure in the treatment of hydrocephalus. Shunt malfunction can be due to various causes, such as failure of the peritoneal (distal) part of the shunt with a frequency of 5% to 47%.

OBJECTIVE

The aim of this study was to compare laparoscopic and laparotomic techniques for implantation of a ventriculoperitoneal shunt.

MATERIAL AND METHODS

We considered a cohort of 304 patients with hydrocephalus, acquired during a 10-year period, who underwent surgical intervention at the Neurosurgical and Surgical Clinics of the University Hospital Brno.

RESULTS

The 304 patients underwent a total of 392 operations, of which 67 (17.1%) were performed using a laparoscopic approach and 325 (82.9%) using a laparotomic approach. In the laparotomy group, 59 (18.2%) interventions were repeated due to complications of the peritoneal part of the shunt, while in the laparoscopy group revisions accounted for only 3 cases (4.5%).

CONCLUSIONS

The laparoscopic technique significantly reduces the risk of complications of the peritoneal part of the shunt, and thus the overall complications associated with the implantation of the ventriculoperitoneal shunt. Laparoscopy is indicated in the case of migration of the peritoneal catheters into the abdominal cavity and is also very helpful in revisions in the case of malfunction of the peritoneal part of the shunt or in the case of previous abdominal surgery. It can explain the anatomical conditions in the abdominal cavity and it is able to treat any incidental pathology.

Clinical significance of the plasminogen activator system in relation to grade of tumor and treatment response in colorectal carcinoma patients

Urokinase (uPA) plays an essential role in the activation of plasminogen to plasmin, and together with its receptor (uPAR), tissue activator (tPA) and urokinase inhibitors (PAI 1, PAI 2, PAI 3 and protease nexin) forms the plasminogen activator system (PAS), a component of metastatic cascade importantly contributing to the invasive growth and angiogenesis of malignant tumours. In our project we examined the expression of uPA, uPAR, PAI 1 and PAI 2 in tumor tissue and we also studied the plasma levels of PAI 1 before and after the initiation of therapy in patients with colorectal carcinoma in relationship to grade of tumor and the treatment response. In our prospective evaluation we included 80 patients treated for adenocarcinoma of the colon and rectum. Analysis of collected data revealed statistically significant evidence of a relationship between the level of PAI 1 in plasma before treatment and grade of the tumor, which increases with tumor grade (p=0.025). We demonstrated that there exists a statistically significant relationship between the expression of PAI 2 (p<0.001) and uPAR (p=0.031) and grade of tumor. We also confirmed a statistically significant relationship between soluble levels of PAI 1 before treatment and therapeutic response (p=0.021). In our group of patients the expression of uPA, uPAR, PAI 1 and 2 in tumor tissue in relation to response to treatment was also assessed. Our results suggest that the greater expression of these parameters in tumor tissue is linked to a worse response to therapy. In conclusion, PAS factors help as a prognostic indicators and could also act as a predictive factor in colorectal carcinoma.

Mechanisms of radiation in a bat group from the genus Pipistrellus inferred by phylogeography, demography and population genetics

Here, we present a study of the Pipistrellus pipistrellus species complex, a highly diversified bat group with a radiation centre in the Mediterranean biodiversity hotspot. The study sample comprised 583 animals from 118 localities representatively covering the bats' range in the western Palearctic. We used fast-evolving markers (the mitochondrial D-loop sequence and 11 nuclear microsatellites) to describe the phylogeography, demography and population structure of this model taxon and address details of its diversification. The overall pattern within this group includes a mosaic of phylogenetically basal, often morphologically distant, relatively small and mostly allopatric demes in the Mediterranean Basin, as well as two sympatric sibling species in the large continental part of the range. The southern populations exhibit constant size, whereas northern populations show a demographic trend of growth associated with range expansion during the Pleistocene climate oscillations. There is evidence of isolation by distance and female philopatry in P. pipistrellus sensu stricto. Although the northern populations are reproductively isolated, we detected introgression events among several Mediterranean lineages. This pattern implies incomplete establishment of reproductive isolating mechanisms in these populations as well as the existence of a past reinforcement stage in the continental siblings. The occurrence of reticulations in the radiation centre among morphologically and ecologically derived relict demes suggests that adaptive unequal gene exchange within hybridizing populations could play a role in speciation and adaptive radiation within this group.

Mediterranean populations of the lesser white-toothed shrew (Crocidura suaveolens group): an unexpected puzzle of Pleistocene survivors and prehistoric introductions

An earlier study revealed the strong phylogeographical structure of the lesser white-toothed shrew (Crocidura suaveolens group) within the northern Palaearctic. Here, we aim to reconstruct the colonization history of Mediterranean islands and to clarify the biogeography and phylogeographical relationships of the poorly documented Middle East region with the northern Palaearctic. We performed analyses on 998-bp-long haplotypes of the mitochondrial cytochrome b gene of 143 samples collected around the Mediterranean basin, including islands and the Middle East. The analyses suggest that the Cypriot shrew belongs to the rare group of relict insular Pleistocene mammal taxa that have survived to the present day. In contrast, the Cretan, Corsican and Menorcan populations were independently introduced from the Middle East during the Holocene. The phylogeographical structure of this temperate Palaearctic species within the Middle East appears to be complex and rich in diversity, probably reflecting fragmentation of the area by numerous mountain chains. Four deeply divergent clades of the C. suaveolens group occur in the area, meaning that a hypothetical contact zone remains to be located in central western Iran.

[Experience with treatment of thoracic empyema during seven years period]

The authors prospectively assembled group of 157 patients treated for empyema thoracic during seven years period. They followed applied methods of the diagnostics and therapy, the length of hospital stay after surgical intervention and its successfulness. The parameters were statistically evaluated. The results showed that surgical intervention substantially influences shortening of the hospital stay and successful cure. In the early stages of the disease thoracoscopic treatment is often sufficient to eliminate the infection. When is indicated later then three weeks after onset of the effusion, then facilitates early decontamination of the empyema cavity and possibility to perform lung decortication. In patients with thoracic empyema, where adequate effusion evacuation can not be reached, the conservative treatment results in prolongation of the hospitalization. Surgical intervention on the contrary the hospital stay, without increase in morbidity or mortality, shortens.

Mitochondrial phylogeography of the long-eared bats (Plecotus) in the Mediterranean Palaearctic and Atlantic Islands

Long-eared bats of the genus Plecotus are widespread and common over most of the western Palaearctic. Based on recent molecular evidence, they proved to represent a complex of several cryptic species, with three new species being described from Europe in 2002. Evolutionary relationships among the different lineages are still fragmentary because of the limited geographic coverage of previous studies. Here we analyze Plecotus mitochondrial DNA sequences from the entire Mediterranean region and Atlantic Islands. Phylogenetic reconstructions group these western Palaearctic Plecotus into two major clades which split at least 5 Myr ago and that are each subdivided into further subgroups. An 'auritus group' includes the traditional P. auritus species and its sister taxon P. macrobullaris (=P. alpinus) plus related specimens from the Middle East. P. auritus and P. macrobullaris have broadly overlapping distributions in Europe, although the latter is apparently more restricted to mountain ranges. The other major clade, the 'austriacus group,' includes the European species P. austriacus and at least two other related taxa from North Africa (including P. teneriffae from the Canary Islands), the Balkans and Anatolia (P. kolombatovici). The sister species of this 'austriacus group' is P. balensis, an Ethiopian endemic. Phylogenetic reconstructions further suggest that P. austriacus reached Madeira during its relatively recent westward expansion through Europe, while the Canary Islands were colonized by a North African ancestor. Although colonization of the two groups of Atlantic Islands by Plecotus bats followed very distinct routes, neither involved lineages from the 'auritus group.' Furthermore, the Strait of Gibraltar perfectly segregates the distinct lineages, which confirms its key role as a geographic barrier. This study also stresses the biogeographical importance of the Mediterranean region, and particularly of North Africa, in understanding the evolution of the western Palaearctic biotas.

Laparoscopic resection of surface metastases in liver--description of the technique

Recently, the laparoscopic approach has been used more frequently for liver resection. The authors describe the method of laparoscopic resection of surface as well as subcapsulary metastases, which had previously been destroyed by radiofrequency ablation. This technique provides relatively easy, complete removal of the tumorous tissue. The disadvantages of the described technique are limited use (it is suitable only for surface lesions) and increased financial costs.

Comparative cytogenetics of hamsters of the genus Calomyscus

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and analyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evolution in this group. Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurred recently within the genus. There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.

[A method for estimating the prevalence of mammary Staphylococcus aureus and Streptococcus agalactiae infections in herds based on an examination of bulk milk samples]

Parallel quantitative determination executed in 92 herds at 107 sampling dates was focused on the counts of major pathogens (Staphylococcus aureus, Streptococcus agalactiae) in bulk milk samples and on the prevalence of the above pathogens in a herd by examination of individual milk samples. The counts of main pathogens were also determined in terms of quantity in rinsing water before milking and in bulk samples in 5 herds with pipeline milking. Tab. I shows the qualitative analysis of the relation. Sensitivity of the method is satisfactory for the pathogens observed (95% and 91%, resp.), but method is less specific for Staph. aureus (67% against 92% Str. agalactiae). Figs. 1 and 2 show coordinate graphs of the results obtained while Figs. 3 and 4 document the distribution of frequency of the particular values in data sets. The values do not exhibit normal distribution (P < 0.01). Spearman's coefficient of rank correlation of bulk milk and individual examinations amounted to 0.823 and 0.900 for Staph. aureus and Str. agalactiae, respectively. Four mathematical models were tested in the course of quantitative analysis, describing the relation between bulk milk examination and individual examination: (1) linear regression, (2) linear regression with fixed starting point, (3) logarithmic regression and (4) irrational function. A model based on the equation of irrational function (4) was found to be best: y = a + bx + c square root of x + k +/- a1 + i(t)c1 square root of x + k1. Tab. II shows the parameters of the equation for examined microorganisms. Correlation coefficients for the above equation are r = 0.733 and r = 0.842 for Staph. aureus and Str. agalactiae, respectively. Prediction curves (Figs. 5 to 8) and confidence regions of prediction curves were also determined for the best model, and a prediction table was constructed (Tab. III). It was confirmed that the milking machines were not a significant source of direct contamination of bulk milk samples with the examined pathogens (Tab. V).

[Validation of TKT medium for detection of Streptococcus agalactiae in bulk milk samples]

A selective medium for quantitative determination of Streptococcus agalactiae in bulk milk samples was tested. Among the medium bases, Edwards medium (EW) supplemented with 6 to 9% (v/v) of carefully washed sheep erythrocytes was proved to be best (Tab. V). The production of sphingomyelinasis C (BHE, Tab. II) or D (COREX, Tab. I) as a supplement supporting the formation of specific hemolytic zones in the medium, was tested in four strains of Staphylococcus aureus and seven strains of Corynebacterium pseudotuberculosis. Submersion aerated cultivation was used for enzyme production; optimum cultivation time is about 100 hours (Figs. 1, 2). To determine the activity of the enzymes produced a screening method was developed applying hemolytic interactions with CAMP factor of Str. agalactiae. Method sensitivity and reproducibility are sufficiently high for the purposes of observation (Tab. III). The produced enzymes did not show any changes in their activity over the whole period of storage under all conditions of storage (32 days/7 degrees C, 48 weeks/-18 degrees C, lyophilizate 48 weeks/20 degrees C). Sphingomyelinasis C is more resistant to heat denaturation, not losing its activity even after being warmed to 85 degrees C for 5 min; sphingomyelinasis D is sensitive to temperatures higher than 50 degrees C (Fig. 3). COREX was selected (sphingomyelinasis D), produced by the strain CNTCC 18/62 of C. pseudotuberculosis. The enzyme was applied either in raw filtrate of the medium (sterilization by repeated membrane filtration) or in prepurified form obtained by cold acetone precipitation, providing the same results. The medium is highly specific and likely enough selective for Str. agalactiae, unlike BHE it does not provide any positive results with UBERIS-factor+strains of Str. uberis (Tab. V). Optimum cultivation time is 18 hours; prolongation of cultivation for more than 24 hours brings about the risk of falsely positive readings (Tab. VI) in the strains of accompanying microflora (Morganella morganii ssp. morganii, delta-hemolytic staphylococci).

[Testing of culture media for detection of Staphylococcus aureus in bulk milk samples]

Three common selective agar culture media were tested with respect to detection of Staphylococcus aureus: Baird-Parker agar (BP), Mannitol-Salt-Phenol agar (MAN) and Vogel-Johnson agar (VJ). All media were cultivated at temperatures of 37 degrees C and 43 degrees C. Three groups of samples were used for investigations: 1, pure cultures of 52 collection strains of S. aureus received from the Czech Microorganism Collection (Tab. I), 2. pure cultures of 75 laboratory strains of S. aureus from samples of cow raw milk and 3,223 bulk samples of cow raw milk. Medium recovery and frequency of medium failure were evaluated, as well as subjective evaluation of medium selectivity and count feasibility was done. The best results of recovery and failure frequency were observed in BP/37 degrees C for all three groups; except the collection strains, in which a distinction from BP/43 degrees C was only moderately significant (P = 0.1; Tab. II), statistically significantly better results of recovery against the other media were determined for BP/37 degrees C in all cases (Tabs. III, VI, IX). No other medium with better results was found out for any other group of samples as regards failure frequency (Tabs. IV, VII, X). Recoveries of BP/43 degrees C ranged from 78 to 95% in comparison with BP/37 degrees C (Figs. 1-3). A group of three media (VJP/37 degrees C, MAN/37 degrees C, MAN/43 degrees C) showed similar results in all groups of samples, statistically significant differences were rare (Tabs. III, VI, IX); recoveries ranged from 55-85% in comparison with BP/37 degrees C (Figs. 1-3). The cultivation on VJ/43 degrees C turned out absolutely inappropriate. Subjective evaluation (Tab. IX) revealed BP/43 degrees C as the best medium, particularly due to the clearly expressed diagnostic traits and high selectivity for accompanying microflora. Enterococci were the most important accompanying microflora in cases of BP/37 degrees C, BP/43 degrees C and VJ/37 degrees C; while in MAN/37 degrees C and MAN/43 degrees C the microflora making the count difficult consisted of representatives of the genera Staphylococcus, Micrococcus and Bacillus. Determinations on different media (except VJ/43 degrees C) well correlated with each other in general (Tabs. V, VIII, XI), the differences in correlations between the pairs of media were not commonly statistically significant.

[Staphylococcus aureus in bulk milk samples]

In the years 1993-1994 the occurrence of Staphylococcus aureus was investigated in bulk milk samples in the area where a Baby Food Factory at Zábreh in Moravia is located, and in Bruntál, Zlín and Policka districts. Evaluation of the results was based on ECC Directive 92/46, while the dynamics of S. aureus presence was followed for the whole period of observation as well as in the particular seasons. A total of 4,485 samples was processed. Out of these, 50.7% contained less than 100 CFU/ml of S. aureus, 41.4% contained 100-500 CFU/ml, 6.73% 500-2,000 CFU/ml and 1.14% contained more than 2,000 CFU/ml (Fig. 1). The samples were divided into three categories: private new-established farms, cooperative and State-owned enterprises in the area of the Zábĕh Factory and others (Zlín, Bruntál and Policka districts). There were highly significant differences in the content of staphylococci (P = 0.01%) between the three categories of samples. Ninety-eight percent of samples from private farms, 96% samples from the Zábreh Factory area and 85% of the other samples comply with the regulation EEC 92/64 (Tab. I) for raw cow's milk for the manufacture of products "made with raw milk" whose manufacturing process does not involve any heat treatment (Fig. 2). The occurrence of S. aureus in the Zábreh Factory area shows an expressive seasonal dynamics (P = 0.005%) with maximum values in winter months (December-March) and minimum values in summer months (July-October)-Fig. 3. The same relationship can be seen on more extensive data files for the particular producers (Fig. 4).(ABSTRACT TRUNCATED AT 250 WORDS)

[Tests of Milkofix, a new preservative preparation for milk samples used for infrared analysis of milk components. I. Verification of its bacteriostatic and bacteriocidal effects and its interference effects]

Hygienic, ecological and health problems of sample preservation for an analysis of basic milk components make us continually to develop a safer chemical preservative substance which will preserve the original sample composition for the time required and which will not influence the analyses. Trzický (1990) proposed Milkofix (M), a preservative substance on the basis of silver compound. The author reports on minimum risks of the use of this preparation, in comparison with traditional preservatives. Preservative efficiency of Milkofix was compared with other preservatives: K2Cr2O7 (C), NaN3 (A) and bronopol (B). The following concentrations were used: A--0.0085 g NaN3 and 0.0630 g NaCl, B--0.0050 g bronopol and 0.0500 g NaCl, C--0.0330 g K2Cr2O7 and 0.0670 g KCl in tablet, M--0.1250 g of the mixture, all amounts are per 25 ml milk. The observed antibacterial efficiency of M could be seen in a slower decrease in actual acidity, and/or in an increase in titratable acidity in M-treated samples unlike untreated ones (N). From the starting value pH 6.3 (Fig. 1), the value of N treatment dropped to 3.8 after two days, the values of M and A treatments dropped to 4.9 after nine days and to 5.7 after twelve days, respectively. As for SH, the values increased within the same interval from 6.5 (2.5 mmol/l) to 28.6 in N, and to 22.3 in M and 9.4 in A (Fig. 3). There was a similar trend when the milk samples were stored at a temperature of 4 degrees C, but the differences between the preservation methods were not so clear in comparison with storage at a temperature of 20 degrees C (Figs. 1 and 3). The standardized SH value of 9.0 (2.5 mmol) for infraanalyzer measurements was exceeded after 24 hours in N samples, after four days in M samples and after 12 days in A samples at a temperature of 20 degrees C. The observation of the growth of microorganism counts (CPM) showed that this growth was slower in M than in N, but faster in the samples of C treatment (Fig. 5). The generative time of CPM in N made 1.6 hours, in M 2.4 hours and in C 7.9 hours. The lag phase of these mixed cultures was 24 hours in M, 60 hours in C and in N treatment the lag phase was zero.(ABSTRACT TRUNCATED AT 400 WORDS)

Normal and benzo(a)pyrene-transformed fetal mouse brain cell. I. Tumorigenicity and immunochemical detection of glial fibrillary acidic protein

Primary cultures of whole brain and cortex cells origination from 14-day-old A/Jax or C3H mouse fetuses were treated with benzo(a)pyrene (B(a)P) for 24 h. After 7 to 8 passages a malignant transformation was observed in the chemically treated whole brain and cortex cultures. Control cultures of cortex remained non-transplantable during the whole experiment (up to 14 passages) whereas in the control cultures originating from whole brain a spontaneous transformation appeared after 11 passages. With horseradish peroxidase-labelled antibody, the specific glial fibrillary acidic protein (GFAP) was detected in both control and transformed total brain and cortex cultures, and in the tumors initiated by the in vitro transformed cells. This finding shows that glialike cells persisted after a long in vitro maintanance and transformation.

[In vitro malignant transformation of fetal hamster brain cells by methylnitrosourea]

Using primary cultures originating from 14 day old fetal Hamster brain, we have obtained a cell line with glial morphology. These cell remain non transplantable during the first year of in vitro culture, but undergo spontaneous transformation during the second year. Following prolonged contact of the glial-like cells with 25 to 50 microgram/ml of methylnitrosourea (MNU), a malignant transformation is observed 5 months after the treatment. The lowest concentrations of (MNU) do not cause malignant transformation, but seem to inhibit (or postpone) the spontaneous transformation. After MNU treatment, cells retain their glial nature.

Molecular forms of acetylcholinesterase: their de novo synthesis in mouse neuroblastoma cells

Rat mouse AChE molecular forms are indistinguishable with respect to their sedimentation coefficients and their evolutive proportions during brain maturation. Among rat or mouse erythrocytes, rat C6 glial cells, and mouse 2A and NS 20 neuroblastoma cells, only neuroblastoma cells showed both the ES and HS molecular forms with a 1:1 proportion for NS 20 cells. All these cells lack a third molecular form (16S), which is present in rat and mouse superior cervical ganglia. After irreversible inhibition of pre-existing NS 20 neuroblastoma AchE, the ES form is first synthesized (de novo synthesis). The HS form begins to appear after a lag time of several hours and represents, 24 h after inhibition, only 15% of the total recovered activity, which is near the initial level. The initial relative proportions return by 2 to 3 days after inhibition. The recovery of the HS form is, for the most part, blocked by actinomycin D, which does not block the recovery of activity itself, which remains as an ES form. It seems that integration of the ES form into the HS form more probably depends on the synthesis of a new messenger RNA, which is required for the synthesis of either new AChE polypeptide chain, polymerization initiating protein or activating enzyme.

Torpedo marmorata acetylcholinesterase; a comparison with the Electrophorus electricus enzyme. Molecular forms, subunits, electron microscopy, immunological relationship

Electron microscopy, sequential degradation by hydrolytic enzymes and the physical-chemical properties of the molecular forms of Torpedo acetylcholinesterase indicate that these molecules are structurally related to each other in the same way as the molecular forms of Electrophorus acetylcholinesterase: all are derived from a complex structure in which three tetrameric groups of subunits are associated with a rod-like 'tail'. In aged preparations the catalytic subunits are split into fragments in a manner similar to those of Electrophorus acetylcholinesterase. Immunological cross-reaction between both enzymes demonstrates the occurrence of common antigenic sites. The enzymes from the two sources, however, are different in their molecular weights and susceptibility to hydrolytic enzymes. Also, Torpedo acetylcholinesterase does not precipitate with either isologous or heterologous antibodies.

[In vitro malignant transformation of fetal hamster brain cells by benzo (a) pyrene]

Hamster embryo brain cells exposed in vitro for 24 hrs. to benzo (a) pyrene and then subcultivated. undergo a morphological transformation. After several passages, transformed cells are capable in most cases of inducing tumors of a special type through intraocular or intracerebral grafting. Histological characterisation of these tumors suggests that they are of glial type. Untreated control brain cells subcultivated for one year, keep their normal characteristics and do not induce tumors when grafted in Hamster.

[Influence of chloride ions on the kinetic parameters of rat brain choline acetyltransferase]

Kinetic properties of Rat brain choline acetyltransferase were studied. Chloride ions promoted the increase of the Km values for the two substrates. Vmax was increased sixty times when chloride ions concentration was elevated from 4.6 to 291 mM.

Dissociated cell cultures from fetal mouse hypothalamus. Patterns of organization and ultrastructural features

Dissociated fetal hypothalamic cells mainly taken from 14 day-old mouse fetuses were grown in vitro for increasing time (9 to 60 days). Soon after inoculation the cells partly reaggregated and attached. The small reaggregates were then interconnected by fibers bundles. After the first week the cultures were composed of a continuous basal monolayer of flat and transparent cells, over which various types of refractile cells were lying in discontinuous areas. The ultrastructural study enabled us to identify these cell types, to describe their spatial relationships, and to follow their evolution with time in culture. The basal cell formed several superimposed layers. With increasing age, they displayed typical features of astrocytes and of ependymal cells. The latter exhibited rhythmic ciliary movements in culture. The overlying cells corresponded to three types which were associated in small clumps: primitive neuro-epithelial cells, maturing as well as mature neurons and typical neurosecretory cells. The latter cells were found as early as 9 days of culture of 14 day-old fetal hypothalamic cells and retained their typical features up to two months. Neuronal processes formed very dense networks at the surface of the cultures and terminated within the basal layers. Axon and dendrites were precociously found and were still present after two months. Within axon terminals dense-core vesicles appeared at the same time as neurosecretory cells. Synaptic vesicles and synaptic junctions were found later on.

[3H] norepinephrine binding by rat glial cells in culture. Lack of correlation between binding and adenylate cyclase activation

Subcellular fractions prepared from rat glial cells in culture (clonal line c6) were used in an attempt to characterize the adrenergic receptor involved in adenylate cyclase activation. Both [3H] norepinephrine binding and enzyme activation were measured under identical experimental conditions. Binding sites for norepinephrine could be detected; their main characteristics were: apparant Km: 4 - 10-6 M, macimal capacity: 20 pmol/mg protein. Their stereospecificity towards structually related drugs was found to be different from the stereospecificity of the receptor involved in adenylate cyclase activation. Thus, 3-methoxydopamine (a competitive inhibitor of norepinephrine for adenylate cyclase activation), phenylephrine (a partial adrennergic agonist) and the blocking agent propranolol were unable to compete with [3H] norepinephrine for binding. On the other hand, several molecules like dopa bearing a catechol group and which are unable to interact with the adenylate cyclase as agonists or competitive inhibitors strongly inhibited [3H] norepinephrine binding. As in several other systems so far studied, the presence on the glial cell's membrane of a large number of "catechol-binding sites" makes it difficult to characterize the beta-adrenergic receptor.

Establishment of a clone of mouse hypothalamic neurosecretory cells synthesizing neurophysin and vasopressin

Hypothalamic cells taken from 14-day-old mouse embryos were cultured for 6 days and transformed with simian virus 40. After cloning, a homogeneous cell population was obtained. Its morphological, Ultrastructural, biochemical, and immunochemical properties were studied. These cells possess ultrastructural features of primitive neurosecretory cells. They synthesize (35)S-labeled protein components that have the molecular weight and isoelectric focusing behavior of, and display the same immunoreactivity as, neurophysin. In addition, a (35)S-labeled peptidic fraction with a molecular weight close to 1000 is synthesized and is radioimmunologically indistinguishable from vasopressin. Immunochemical staining shows that both neurophysin and vasopressin are localized in the cytoplasm. These observations strongly suggest that a clone of mouse hypothalamic neurosecretory cells has been obtained with the synthesizing capacities of secretory neurons of the magnocellular hypothalamic nuclei.