Tolerance and short term efficacy of rituximab in 43 patients with systemic autoimmune diseases

OBJECTIVE

To assess the tolerance and efficacy of rituximab in patients with various autoimmune diseases seen in daily rheumatological practice.

METHODS

866 rheumatology and internal medicine practitioners were contacted by e-mail to obtain the files of patients treated with rituximab for systemic autoimmune diseases. Patients with lymphoma were analysed if the evolution of the autoimmune disease could be evaluated.

RESULTS

In all, 43 of 49 cases could be analysed, including 14 with rheumatoid arthritis (RA), 13 with systemic lupus erythematosus (SLE), six with primary Sjogren's syndrome (pSS), five with systemic vasculitis, and five with other autoimmune diseases. Rituximab was prescribed for lymphoma in two patients with RA and two with pSS. In the 39 other cases, rituximab was given because of the refractory character of the autoimmune disease. The mean follow up period was 8.3 months (range 2 to 26). There were 11 adverse events in 10 patients and treatment had to be discontinued in six. Efficacy was observed in 30 patients (70%): RA 11, SLE 9, pSS 5, vasculitis 2, antisynthetase syndromes 2, sarcoidosis 1. The mean decrease in corticosteroid intake was 9.5 mg/d (range 0 to 50) in responders. Seven patients experienced relapse after mean 8.1 months (5 to 15). Three patients died because of refractory autoimmune disease.

CONCLUSIONS

Despite absence of marketing authorisation, rituximab is used to treat various refractory autoimmune diseases in daily rheumatological practice. This study showed good tolerance and short term clinical efficacy, with marked corticosteroid reduction in patients with SLE, pSS, vasculitis, and polymyositis.

Methadone maintenance vs 180-day psychosocially enriched detoxification for treatment of opioid dependence: a randomized controlled trial

CONTEXT

Despite evidence that methadone maintenance treatment (MMT) is effective for opioid dependence, it remains a controversial therapy because of its indefinite provision of a dependence-producing medication.

OBJECTIVE

To compare outcomes of patients with opioid dependence treated with MMT vs an alternative treatment, psychosocially enriched 180-day methadone-assisted detoxification.

DESIGN

Randomized controlled trial conducted from May 1995 to April 1999.

SETTING

Research clinic in an established drug treatment service.

PATIENTS

Of 858 volunteers screened, 179 adults with diagnosed opioid dependence were randomized into the study; 154 completed 12 weeks of follow-up.

INTERVENTIONS

Patients were randomized to MMT (n = 91), which required 2 hours of psychosocial therapy per week during the first 6 months; or detoxification (n = 88), which required 3 hours of psychosocial therapy per week, 14 education sessions, and 1 hour of cocaine group therapy, if appropriate, for 6 months, and 6 months of (nonmethadone) aftercare services.

MAIN OUTCOME MEASURES

Treatment retention, heroin and cocaine abstinence (by self-report and monthly urinalysis), human immunodeficiency virus (HIV) risk behaviors (Risk of AIDS Behavior scale score), and function in 5 problem areas: employment, family, psychiatric, legal, and alcohol use (Addiction Severity Index), compared by intervention group.

RESULTS

Methadone maintenance therapy resulted in greater treatment retention (median, 438.5 vs 174.0 days) and lower heroin use rates than did detoxification. Cocaine use was more closely related to study dropout in detoxification than in MMT. Methadone maintenance therapy resulted in a lower rate of drug-related (mean [SD] at 12 months, 2.17 [3.88] vs 3.73 [6.86]) but not sex-related HIV risk behaviors and in a lower severity score for legal status (mean [SD] at 12 months, 0.05 [0.13] vs 0.13 [0.19]). There were no differences between groups in employment or family functioning or alcohol use. In both groups, monthly heroin use rates were 50% or greater, but days of use per month dropped markedly from baseline.

CONCLUSIONS

Our results confirm the usefulness of MMT in reducing heroin use and HIV risk behaviors. Illicit opioid use continued in both groups, but frequency was reduced. Results do not provide support for diverting resources from MMT into long-term detoxification.

Epidemiology of adult Still's disease: estimate of the incidence by a retrospective study in west France

OBJECTIVES

To estimate the incidence of adult Still's disease (ASD) and to specify, if possible, associated factors.

METHODS

A retrospective study of the populations of the Brittany and Loire regions in west France was made from 1 January 1982 to 31 December 1991. All internal medicine and rheumatology practitioners of these regions were consulted.

RESULTS

Sixty-two (62) cases were reported (93% response). The disease incidence calculated over five years was 0.16 per 100,000 inhabitants in the study population. There was no sex bias (sex ratio 1.06 in ASD v 1.05 in the overall population. The mean age of the study population was 36 years, with two peaks of distribution at 15-25 and 36-45 years. A history of allergy was present in 23% of patients (n = 14). In two patients, it was possible to correlate an environmental allergen to exacerbation of ASD.

CONCLUSION

The yearly incidence of ASD was estimated to be 0.16 per 100,000 inhabitants. However, it was not possible to incriminate any infectious, toxic, or genetic factors in exacerbation of the disease.

Prevalence of spondyloarthropathies in France: 2001

OBJECTIVE

To estimate the prevalence of spondyloarthropathies (SpAs) in France in a multiregional representative sample in the year 2001.

METHODS

A two stage random sample was constituted in seven areas from the national telephone directory and the next birthday method in each household. Interviewers were patient-members of self help groups trained to administer telephone surveys using a validated questionnaire for detecting inflammatory joint disease. Quality of data collection was controlled periodically. SpA was confirmed by the patient's rheumatologist or by clinical examination. Prevalence estimates after probability sampling correction were standardised for age and sex (1999 national census).

RESULTS

Among the 15 219 anonymous telephone numbers selected, 3.6% were places of work or secondary residences and were excluded. The phone interview participation rate ranged across regions from 55.1 to 69.9%. 3554 men and 5841 women were included in the study. Twenty nine cases of SpA were confirmed. All but one fulfilled ESSG criteria. Mean age was 47 years (range 21-78). The overall prevalence standardised for age and sex was 0.30% (95% confidence interval (CI) 0.17 to 0.46). Prevalence was similar in women (0.29% (95% CI 0.14 to 0.49)) and men (0.31 % (95% CI 0.12 to 0.60)). Geographical analysis by department clustering found no significant differences. The prevalence of SpA was as high as that of rheumatoid arthritis.

CONCLUSION

Prevalence of SpA in France was 0.30% in 2001, with no difference between women and men. Ankylosing spondylitis and psoriatic arthritis were the most common SpA subsets.

Spinal cord infarction: clinical and magnetic resonance imaging findings and short term outcome

BACKGROUND

Most studies on spinal cord infarction have been conducted in single centres; they usually consisted of case reports, or of larger series of patients recruited over a large period of time, with heterogeneous diagnostic procedures. Therefore, the clinical and radiological presentation of spinal cord infarcts and their short term outcome remain poorly understood.

OBJECTIVE

To define clinical and magnetic resonance imaging (MRI) findings, and short term outcome in patients with spinal cord infarcts.

METHODS

The authors prospectively included patients within 10 days of onset. An MRI scan was required and repeated when initially normal.

RESULTS

Twenty eight consecutive patients were included over a 24 month period in 16 neurological centres. The infarct was cervical in seven patients, thoracic in three, thoracolumbar in 15, and restricted to the conus in three. On axial MRI scans the infarct was located in the central territory of the anterior spinal artery in 21 patients, and in the peripheral arterial territory in three. At month two, 15 patients had a good outcome and 13 had a poor outcome, including three deaths. Patients who, at onset, could not walk, had bladder dysfunction, or proprioceptive deficits were more likely to have a poor outcome. At month two, pain had occurred in 10 of the 25 survivors and was associated neither with the initial severity, nor the extent of the infarct on MRI.

CONCLUSION

The two month outcome mainly depends on the initial severity of the neurological deficit; however, a few patients with a severe impairment at onset had a good outcome, especially when proprioception remained normal at onset. The study does not support the hypothesis that pain occurs more frequently in small spinal infarcts.

Prevalence of rheumatoid arthritis in France: 2001

BACKGROUND

Prevalence estimates of rheumatoid arthritis (RA) vary across Europe. Recent estimates in southern European countries showed a lower prevalence than in northern countries.

OBJECTIVES

To estimate the prevalence of RA in France in a multiregional representative sample in the year 2001.

METHODS

A two stage random sample was constituted in seven areas (20 counties) from the national telephone directory of households and by the next birthday method in each household. Patient-interviewers, member of self help groups, were trained to administer telephone surveys using a validated questionnaire for case detection of inflammatory rheumatism, and conducted the survey under quality control. All suspected cases of RA were confirmed by their rheumatologist or by clinical examination. Prevalence estimates after probability sampling correction were standardised for age and sex (national census 1999).

RESULTS

An average response rate of 64.7% (two stages combined) led to a total of 9395 respondents. Standardised prevalence was 0.31% (95% confidence interval 0.18 to 0.48) for RA, 0.51% in women and 0.09% in men, with a higher age-specific prevalence in the 65-74 year age band. A geographical analysis of county clustering showed significant variation across the country.

CONCLUSION

This national multiregional cooperative study demonstrates the usefulness of working in association with patients of self help groups. It showed a similar prevalence of RA to that of the spondyloarthropathies estimated concomitantly during the survey. It provides a reliable basis for definition of population targets for healthcare delivery and drug treatments.

Localization of the RNA polymerase I transcription factor hUBF during the cell cycle

Autoantibodies directed against nucleoli that recognized a doublet of 97–94 kDa in HeLa nuclear protein extracts were identified. The two polypeptides bound equal amounts of antibody, and each was recognized by antibodies affinity purified using the other polypeptide. These antigens were localized in the secondary constriction of PtK1 cells, i.e. the nucleolar organizer regions (NORs) where ribosomal genes accumulate. They were observed in human cells in the same sites as the NOR-silver-stained proteins. The molecular mass of the antigens, their characteristics in Western blotting and their localization in nucleoli and NORs during mitosis are consistent with them being RNA polymerase I transcriptional factor, UBF. This identification was confirmed on Western blotted proteins by their identical labelling patterns, using these autoantibodies and an anti-mUBF antibody that had been previously described. We obtained definitive evidence that these autoantibodies recognize UBF by the strong positive labelling of purified hUBF (1 to 4 ng). During interphase, these autoantibodies directed against UBF labelled in a folded filament pattern as small beads that may correspond to individual transcriptional units. In electron microscopy, the antibodies were observed in the dense fibrillar component (DFC) of the nucleoli and at the periphery of the fibrillar centers (FCs). At the end of G2 phase, transcription inactivation was concomitant with the gathering of UBF at mitotic NORs. UBF was not equally distributed between NORs in human cells: some NORs scored negative (2 to 4) and the intensity of labelling of positive NORs (6 to 8) differed. In confocal microscopy, 3-dimensional analysis of mitosis indicated that UBF remained associated with NORs during all mitotic stages and that there was equal partition of UBF between the daughter cells. The relationship between proteins associated with the NORs and ribosomal gene transcription is discussed.

Management of nontuberculous infectious discitis. treatments used in 110 patients admitted to 12 teaching hospitals in France

The optimal management of pyogenic discitis is not agreed on. No randomized clinical trials of short-course or oral antibiotic regimens have been published to date. To shed light on this issue, we reviewed the management of patients admitted for pyogenic discitis to one of 12 networked rheumatology departments. In this cross-sectional observational study, each department included the first ten patients admitted starting in January 1997 for treatment of pyogenic discitis. One hundred ten patients met the inclusion criteria, 67 men and 43 women, with a mean age of 60.6 +/- 13.7 years (range, 17-86 years). Mean time from symptom onset to diagnosis was 39.6 +/- 39.8 days (range, 24 h-240 days). Blood cultures were positive in 47.3% of patients, and the percutaneous discal and vertebral biopsy in 63.6% of cases; these two investigations identified the causative organism in 79 cases (72.8%). Mean duration of the rheumatology department stay was 31.3 +/- 14.1 days (range, 4-78 days). Antibiotics were given intravenously to 103 (93.6%) patients, for a mean of 25.5 +/- 17.6 days (range, 4-124 days); duration of intravenous antibiotic therapy was longer than 4 weeks in 36.5% of patients. Only seven (6.4%) patients received primary oral antibiotics with no parenteral antibiotics. One hundred patients were given oral antibiotics at the same time as and after intravenous antibiotics, for a mean duration of 87.2 +/- 43.6 day (range, 20-278 days); Bracing was used in 98 (89.1%) patients. Although antibiotic selection was rational and in agreement with current recommendations, wide differences were noted across centers regarding intravenous treatment duration, hospital stay duration, and total treatment duration.

Cranial pachymeningitis of unknown origin: a study of seven cases

We report seven patients with cranial pachymeningitis of unknown origin in whom the main clinical features were headaches, ataxia, and cranial nerve palsies. CSF showed inflammatory changes. CT and MRI showed thickening of the falx and of the tentorium. The clinical course was chronic. Four patients improved with prednisolone but became steroid-dependent: in two cases, radiotherapy had no lasting improvement and in one, azathioprine permitted a reduction of the corticosteroids. Five patients had biopsy of the tentorium cerebelli or of the temporal dura mater. In two cases, autopsy revealed extensive pachymeningitis without parenchymal changes. In all instances, microscopic examination of the dura mater showed a cellular infiltrate of polymorphic cells; there were no epithelioid granulomas. Review of the literature discloses seven similar cases. We discuss the relationship of these lesions with inflammatory meningeal masses, the focal pachymeningitis of the Tolosa-Hunt syndrome, and multifocal fibrosis.

Attraction of the Parasitic Mite Varroa to the Drone Larvae of Honey Bees by Simple Aliphatic Esters

An important parasitic threat to honey bees, the mite Varroa jacobsoni, is attracted to its major prey, drone larvae, by methyl and ethyl esters of straight-chain fatty acids, in particular methyl palmitate. These esters were extracted from drone larvae with n-hexane and were identified by gas chromatography-mass spectrometry. Their behavioral effect was evaluated with the use of a four-arm airflow olfactometer.

Determination of nucleotides in fish tissues using capillary electrophoresis

Capillary electrophoresis has been applied to quantitate nucleotide degradation in fish tissues, to provide a basis for determining the K value, an indicator of fish freshness. The three major compounds, inosine monophosphate (IMP), inosine (HxR), and hypoxanthine (Hx) were distinctively separated at 416 V/cm applied potential, 100 mM CAPS buffer, pH 11. There was a good correlation between the peak area and the nucleotide concentration. By using a short distance (22 cm) from the sample entrance to the detector, the identification and determination of these compounds in each sample were completed within 15 min. The results obtained correlated very well with those obtained by enzymatic assays. The capillary was completely regenerated with 1 N NaOH, to dissociate all bound materials from the capillary wall, mainly cations in the fish extract. This provided the same silica surface for repeated runs, resulting in reproducible electropherograms.

Radial force of coronary stents: a comparative analysis

High radial force has become an essential feature of new coronary stents. These stents are expected to exhibit sufficient radial force and minimum radial recoil when deployed in atheromatous lesions of various morphologies. The aim of this study was to compare the radial force of 17 coronary stents in vitro (Anglodynamics, ACS Multilink, AVE Micro II and GFX, Bard XT, Biocompatibles PC, Cook GR II, Cordis Crossflex, Hexacath Freedom, Johnson & Johnson PS 153'PS 154, and Crown, Medtronic Wiktor and BeStent BEL-15, Saint-Come SC 1616, Scimed Nir 7 and 9). Two in vitro mechanical tests were performed to assess the stent radial force. The first test measured the deformation of coronary stents in a V-stand by using a deformation controlled by a dynamometer based on a longitudinal generatrix. The precision was of 1 micron. This comparative test highlighted the appreciable variation in behavior of the range of tested stents in terms of resistance to local compression. The line graphs obtained show a very small (and in some cases nonexistent) purely elastic behavior area in the stents, with this result reflecting a small (<0.4 Newtons) range of forces applied to all stents. Above this value, the stents did not return to their size before compression and the line graph remains approximately linear for a long period. It was therefore possible to distinguish between two families of stents on the basis of the presence or absence of this elastic area. In the second test, the stent was deployed in a 3.0-mm elastic tube and a pressure gradient created between the interior and exterior of the tube. The precision was of 50 microns. A typical line graph of the pressure-diameter relationship was recognizable for a given stent. No difference in behavior between the different coronary stents was noted up to 0.3 x 10(5) Pa; subsequently, after 0.3 x 10(5) Pa, sizable deformation differences were visible between the least resistant stent, the BeStent BEL-15, and the most resistant stent, the Crossflex.

Separation, characterization and sexual heterogeneity of multiple putative odorant-binding proteins in the honeybee Apis mellifera L. (Hymenoptera: Apidea)

According to precise molar mass determined by mass spectrometry and N-terminal sequence, some 25 odorant-binding-like proteins were characterized from the antennae and legs of worker and drone honeybees. Antennal specific proteins, composed of six different molecules, were classified into three subclasses according to N-terminal sequence homology. The major sexual difference was shown to lie in the relative abundance of these antennal specific proteins and in the occurrence of a drone-specific isoform. At least 19 other related proteins were found to occur in antennae and legs, forming another class showing homology with insect OBP. Genotype comparison of two honeybee races revealed a variability limited to this second class. Provided that these odorant-binding-like proteins are indeed able to bind odorants or pheromones, the question of whether their peculiar multiplicity contributes to the remarkable capacity of the honeybee to discriminate among a wide range of odor molecules is raised.

Sterically stabilized BGTC-based lipoplexes: structural features and gene transfection into the mouse airways in vivo

BACKGROUND

Colloidal stability of lipid/DNA aggregates is a major requirement for cationic lipid-mediated transfection which is particularly difficult to fulfil at the high DNA concentrations used for in vivo gene delivery. Thus, we have investigated the potential of poly(ethyleneglycol) (PEG) conjugates for steric stabilization of lipoplexes formed by bis(guanidinium)-tren-cholesterol/dioleoyl phosphatidylethanolamine (BGTC/DOPE) liposomes, a class of cationic liposomes we have developed over the past few years.

METHODS AND RESULTS

We demonstrate that adequate lipophilic PEG derivatives can stabilize BGTC/DOPE lipoplexes formed at high DNA concentration. We also report the results of cryotransmission electron microscopy studies indicating that PEG-stabilized lipoplexes form DNA-coated structures which assemble into clusters exhibiting various complex morphologies. Finally, we report data from in vivo transfection experiments suggesting that PEG-mediated colloidal stabilization of concentrated lipoplex solutions may allow enhanced transfection of the mouse airways via intranasal administration.

CONCLUSION

Our results represent an important step towards the design of multimodular BGTC-based systems for improved in vivo gene transfection.

The deutocerebrum of the cockroach Blaberus craniifer Burm. Spatial organization of the sensory glomeruli

The objective of this work is to describe the glomerular organization of the deutocerebrum in Blaberus craniifer and to test the hypothesis that the glomeruli are identifiable. The problem is studied using the techniques of analytical geometry, i.e., by measuring the location of the glomeruli in cartesian coordinate systems. Computerized geometrical and statistical techniques are described for the three-dimensional reconstruction and quantitative study of these brain structures. The invariance of the glomerular organization, and consequently the identifiability of the glomeruli, is based on three criteria: (1) the number of glomeruli per hemideutocerebrum (hDTC) is a constant (109); (2) the position of the glomeruli is symmetrical in the two sides of one individual and identical in the same side of two individuals, except for small local variations,(3) the dimensions of two positionally homologous glomeruli are statistically equal in the same and in different individuals, except for a macroglomerulus which is found only in the male. The causes of variability, from experimental and biological origin, are discussed and quantitatively evaluated. The interindividual biological variability, not ascribable to differences in size between brains, expressed as a 95% interval, is estimated to be 27 micrometer for the location of glomeruli and 12 micrometer for the diamter of glomeruli.

Identification and characterization of a new set of nucleolar ribonucleoproteins which line the chromosomes during mitosis

We investigated the perichromosomal architecture established during mitosis. Entry into mitosis brings about a dramatic reorganization of both nuclear and cytoplasmic structures in preparation for cell division. While the nuclear envelope breaks down, nuclear proteins are redistributed during chromosome condensation. Some of these proteins are found around the chromosomes, but little is known concerning their nature and function. Ten autoimmune sera were used to study the microenvironment of chromosomes and, in particular, the chromosome periphery. They were selected for their anti-nucleolar specificity and were found to recognize three nucleolar proteins that coat the chromosomes during mitosis. The distribution of these antigens was followed through the cell cycle by confocal laser scanning microscopy. The antigens dispersed very early during prophase and simultaneously with the chromosome condensation suggesting a correlation between these two processes. The antigens have apparent molecular weights of 53, 66, and 103 kDa on SDS-PAGE migration. Elution of the antibodies and immunopurification showed that they are RNA-associated proteins. The coimmunoprecipitating RNA moiety involved in these RNPs appeared to be U3, but the antigens are not related to the fibrillarin family. Therefore, small nucleolar RNPs follow the same distribution during mitosis as that described for small nuclear RNPs. Possible functions for these antigens are discussed.

Comparison of the angiotensin II receptor antagonist irbesartan with atenolol for treatment of hypertension

In this multicenter, double-blind study, the antihypertensive efficacy and safety of irbesartan were compared with those of atenolol in patients with mild-to-moderate hypertension. Following a 4- to 5-week placebo lead-in period, 231 patients with seated diastolic blood pressure (SeDBP) 95-110 mmHg were randomized to irbesartan 75 mg or atenolol 50 mg once daily for 24 weeks. Doses were doubled at Week 6 for SeDBP > or = 90 mmHg. At Week 12, or anytime thereafter, doses were doubled for SeDBP > or = 90 mmHg if not done at Week 6, and hydrochlorothiazide and then nifedipine were added. Efficacy was determined by change from baseline in blood pressure and by therapeutic response rates. Safety was assessed by monitoring adverse events (AEs). Both treatments significantly lowered blood pressure from baseline. There were no significant differences between treatment groups with respect to blood pressure changes or therapeutic response. Atenolol significantly reduced seated heart rate compared with irbesartan at Week 12. The incidences of serious AEs and discontinuations due to AEs were approximately twice as high in the atenolol group compared with the irbesartan group. Thus, in comparison to atenolol, irbesartan < or = 150 mg provided at least equivalent blood pressure control while demonstrating an excellent safety and tolerability profile.

The three-dimensional organization of ribosomal genes and the architecture of the nucleoli vary with G1, S and G2 phases

The three-dimensional (3-D) organization of the nucleolus, a defined nuclear territory containing tandem repeats of the ribosomal genes (rDNA), was investigated in PtK1 cells. Identification of the interphase stages was performed in single cells using DNA quantification by cytometry for the G1 and G2 phases while the S phase was identified by immunolabelling of the proliferating cell nuclear antigen (PCNA). The 3-D organization of the rDNA in the nucleolus was analyzed by fluorescence in situ hybridization using confocal microscopy. All the rDNA was located inside the nucleolar structures during all stages and the two rDNA loci were orthogonal. The rDNA was heterogeneously distributed in each nucleolus during G1, S and G2, with alternate sites of clustered genes (spots) and of genes in more extended configurations. The number of spots (4 to 6 in G1) increased during S phase (7 to 12) and their 3-D organization was progressively relaxed from G1 to G2. Double spots in G2 could reflect a similar gene organization of two chromatids. During mid-S phase, PCNA co-localized with some clustered genes (spots), indicating that rDNA replication occurs inside nucleoli and at different sites of the same locus simultaneously. The evaluation of the rDNA transcription units in 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB)-treated cells indicated a mean of 16 units per G1 nucleus and 25 units per G2 nucleus. For G1 and G2, the fine 3-D structure of nucleoli was reconstructed using ultrathin serial sections after specific contrast of DNA and RNA, digitization of the serial section images and computer-assisted 3-D architecture. Fibrillar centers (FCs) formed discrete structures (about 10 in G1 and 20 in G2) connected by a network of the dense fibrillar component. The 3-D arrangement of the FCs in G1 and G2 are similar to the rDNA spots. In conclusion, the architecture of the nucleoli during interphase reflects the distribution of the rDNA that is characterized by alternation of clustered and extended genes.

Developmental study of afferented and deafferented bee antennal lobes

The role of antennal sensory projections on the ontogeny of the bee antennal lobe was analyzed using both light and transmission electron microscopy. Normal and deafferented developing antennal lobes were examined. The results obtained show that (1) initiation of synaptogenesis in the antennal lobe is independent of the arrival of sensory inputs; (2) sensory inputs are necessary for setting up the glomerular antennal lobe organization; (3) regressive events, such as the reduction of synapse density, occur during the development of the antennal lobe; and (4) glomeruli formation appears as related to glia development.

Non-specific cross-reactivity of hydrophobic serum IgE to hydrophobic drugs

The purpose of this work was to study the involvement of serum hydrophobic IgE in non-specific cross-reactions with hydrophobic drugs such as cyclohexenyl derivatives. Hydrophobic IgE were detected by radioimmunoassay. The results were expressed as the percentage of labelled anti-IgE which were adsorbed to the drug solid phase via IgE of the patient serum. Phenyl-Sepharose IgE-RIA was at 4.6 +/- 0.7%, 125 +/- 6.5% and 17.8 +/- 8.9% in control subjects (n = 24), in atopic patients with positive Phadiatop (n = 30) and in patients with drug allergy (n = 23), respectively. We selected five patients who were allergic to either penicillin, propofol, glafenin or paracetamol and who had a Phenyl-Sepharose IgE-RIA greater than 20%. In these five cases, IgE-RIA were positive (percentage at least twice more than that obtained with control sera) with all the solid phases prepared with hydrophobic drugs such as penicillin, propofol, glafenin, paracetamol and mexiletine. Inhibition of IgE binding by monoethylene-glycol showed that the cross-reactivity was due to hydrophobic binding of IgE to the drug. Three of the five patients were allergic to penicillin and underwent on adverse reaction against another cyclohexenyl derivative, namely propofol and glafenin. In conclusion, we have observed the presence of 'hydrophobic IgE (with positive Phenyl-Sepharose RIA)' in 64% of patients allergic to a hydrophobic drug.

Three-dimensional organization of micronuclei induced by colchicine in PtK1 cells

In PtK1 cells micronucleated by colchicine, we previously demonstrated that some micronuclei contain a single chromosome. Here, we investigated interphase chromosome organization in micronucleated PtK1 cells using conventional electron microscopy and three-dimensional computer reconstruction. The distribution of micronuclei was not always polarized, but in some cells they formed a ring. When this occurred, centrioles and Golgi apparatus were located inside the ring. On freeze-fracture replicas, we observed that nuclear pore distribution among the micronuclei was heterogeneous, and on thin sections some micronuclei displayed an incomplete nuclear envelope, with gaps in the double membrane and areas without lamina or condensed chromatin. By autoradiography, we showed that the fibrillar dots were not sites of active transcription. We applied three-dimensional reconstruction to one micronucleated cell containing 22 micronuclei whose size indicated that each micronucleus probably contained one chromosome. In this cell we demonstrated that only the smallest micronuclei had an incomplete nuclear envelope. The presence in micronuclei of either nucleoli or fibrillar dots was found to be mutually exclusive. These dots might constitute stores of nucleolar proteins which migrate into micronuclei possessing no ribosomal genes. In NOR-bearing micronuclei, the structural organization was similar to that of diploid nuclei: the nucleoli were attached to the nuclear membrane and a nucleolar canal was seen, even in single-chromosome spherical micronuclei. Taken together, these findings indicate that in the diploid nuclei of PtK1 cells, the three-dimensional organization of the nucleolar domain seems to be directly controlled by the X-chromosome.

3-D organization of ribosomal transcription units after DRB inhibition of RNA polymerase II transcription

In each bead of the nucleolar necklace, using adenosine analog DRB-treated PtK1 cells, we investigated the three components of rDNA transcription, i.e. the gene, transcription factor UBF and transcripts. In situ hybridization revealed the unraveling and 3-D dispersion of most of the rDNA coding sequences within the nucleus. The signals were small, of similar intensity and tandemly organized in the necklace. This observation is compatible with the fact that they might correspond to single gene units. Active transcription was visualized in these units, demonstrating that they were active functional units. Transcript labeling was not similar for each unit, contrary to UBF labeling. UBF and rRNA transcripts were only partially colocalized, as demonstrated by 3-D image analysis and quantification. As visualized by electron microscopy, the necklace was composed of a small fibrillar center partially surrounded by a dense fibrillar component. The 3-D arrangement of this individual unit in the necklace, investigated both by confocal and electron microscopy in the same cells, showed that the individual beads were linked by a dense fibrillar component. The reversibility of this organization after removal of DRB indicated that the beads in the necklace are certainly the elementary functional domain of the nucleolus. In addition, these results lead us to suggest that the organization of a functional domain, presumably corresponding to a single gene, can be studied by in situ approaches.

Fate of specific nucleolar perichromosomal proteins during mitosis: cellular distribution and association with U3 snoRNA

In mammalian cells, the nucleoli disintegrate during mitosis and some nucleolar proteins disperse at the periphery of all chromosomes forming a novel class of chromosomal passenger proteins. The nucleolar components which participate in the formation of this perichromosomal layer have been investigated to elucidate the role of these perichromosomal proteins in the assembly and disassembly of the nucleoli. i) Electron microscopy immunolabelling reveals that these proteins are predominantly located in the granular component of the nucleoli during interphase. ii) Immunoprecipitation data suggest that they are distributed at the chromosome periphery in association with U3 small nucleolar RNA (snoRNA). In addition, the distribution of U3 snoRNA visualized by in situ hybridization, is similar to that observed for the perichromosomal proteins. iii) In cells which possess a nucleolar remnant during mitosis, U3 snoRNA and perichromosomal proteins were found both in the perichromosomal layer and in the nucleolar remnant. iv) Some of these proteins are conserved from yeast to man such as fibrillarin and a protein of 52 kDa. v) The location of these proteins observed in yeast by confocal microscopy shows that they are not dispersed during mitosis. Their partition between the two daughter cells is performed by scission of nucleolar structures forming a rod during the budding process. Therefore RNP complexes related to the processing steps of ribosome biogenesis in mammalian cells quit the nucleolus in late G2 and associate with the chromosome periphery until late telophase. They associate in the perichromosomal layer in human and PtK1 cells and both in the perichromosomal layer and the nucleolar remnant in CHO cells.