Simultaneous memory effects in the stress and in the dielectric susceptibility of a stretched polymer glass

We report experimental evidence that a polymer stretched at constant strain rate λ[over ̇] presents complex memory effects after λ[over ̇] is set to zero at a specific strain λ_{w} for a duration t_{w}, ranging from 100s to 2.2×10^{5}s. When the strain rate is resumed, both the stress and the dielectric constant relax to the unperturbed state nonmonotonically. The relaxations depend on the observable, on λ_{w} and on t_{w}. Relaxation master curves are obtained by scaling the time and the amplitudes by ln(t_{w}). The dielectric evolution also captures the distribution of the relaxation times, so the results impose strong constraints on the relaxation models of polymers under stress and they can be useful for a better understanding of memory effects in other disorder materials.

A dynamical model for the control of the gonadotrophin-releasing hormone neurosecretory system

The gonadotrophin-releasing hormone (GnRH) neurosecretory system involves both endocrine neurones and associated brain cells responsible for the control of GnRH release into the pituitary portal blood. Alternation between a pulsatile regime and the pre-ovulatory surge is the hallmark of GnRH secretion in ovarian cycles of female mammals. In previous studies, we have introduced a mathematical model of the pulse and surge GnRH generator and derived appropriate dynamics-based constraints on the model parameters, both to reproduce the right sequence of secretion events and to fulfil quantitative specifications on GnRH release. In the present study, we explain how these constraints amount to embedding time- and dose-dependent steroid control within the model. We further examine under which conditions the oestradiol-driven surge may be withdrawn by pre-surge progesterone administration and simulate both oestradiol and progesterone challenges in the pulsatile regime.

Evaporation of liquids and solutions in confined geometry

We describe a drying setup where a liquid droplet is confined between two circular glass plates and allowed to evaporate. Optical imaging of the shrinking droplet provides the temporal evolution of the solvent volume. For a pure liquid, we measure the diffusion coefficient of the evaporating gas with a good accuracy. For a solution, the slowing down of evaporation by progessive concentration of the solute yields a direct measurement of the solvent activity.

Growth kinetics of the granulosa cell population in ovarian follicles: an approach by mathematical modelling

This paper describes, from a mathematical viewpoint, the cellular changes in the granulosa of ovarian follicles during their terminal development. A dynamic model takes into account the processes of (1) cell division, (2) exit from the cell cycle towards differentiation, and (3) apoptotic cell death. Proliferative cells leave the cycle in an irreversible way. The risk of entering apoptosis applies to non-cycling cells. Changes in the cell numbers and in the growth fraction are derived from differential equations. The transitions between the different cell states are ruled by time-dependent rates. Numerical applications of the model concern ovulating and degenerating ovarian follicles in the ewe. The main feature of the ovulating case is the progressive exhaustion of the proliferating compartment for the benefit of the non-cycling cells. From an initial mainly proliferative state the granulosa progressively switches to a highly differentiated state, so that the growth fraction continuously decreases. In the atretic cases, the pattern of changes in the total viable cell number is influenced by the follicular age at the onset of the apoptotic process and by the intensity of the cell death rate. As apoptosis affects the non-cycling cells, the growth fraction is no longer strictly decreasing. The sensitivity of the model to the parameters is studied in a more general framework than the granulosa cell population.

Quantitative and qualitative assessment of milk production after pharmaceutical induction of lactation in the mare

The induction of lactation is performed in ruminants by steroidogenic impregnation, followed by drugs intended to increase prolactin secretion. The aim of this study was to induce lactation in barren mares and to evaluate milk production. Five treated and 5 control mares were used in June and September in year 1, and 12 mares were used in year 2. Mares were administered a vaginal pessary (500 mg altrenogest and 50 mg estradiol benzoate) for 1 week. The 2nd week, another sponge with 100 mg estradiol benzoate was administered, together with 50 mg/100 kg body weight (BW) sulpiride in oil (IM q12h). All mares were milked by hand. Drug treatment was stopped after I L was obtained. Milk production and composition and plasma prolactin concentration were measured. In year 2, the same steroid treatment was applied, but mares received sulpiride (n = 6) or domperidone (1.1 mg/kg PO q12h) (n = 6). A milking machine and oxytocin injections 1 minute before the start of milking were used. In year 1, all treated mares started milking within 1-5 days after sulpiride treatment. Mean daily milk production was 0.88 +/- 0.52 L/500 kg BW. Milk immunoglobulin G (IgG) contents increased in all mares (IgG concentration range, 14-92 g/L). Plasma prolactin increased during sulpiride treatment (range. 27.7 +/- 2.9 to 43.7 +/- 6.7 ng/mL [before] to 289.0 +/- 7.8 ng/mL during treatment, P < .001). In year 2, results were similar to those in year 1, with peak IgG concentrations ranging from 4.2 to 106.7 g/L and a larger daily milk production (3.13 +/- 0.75 with sulpiride and 3.45 +/- 0.51 L/500 kg BW with domperidone). In conclusion, lactation can be induced in mares within 2 weeks, and some mares produce good-quality colostrum.

Mathematical model of FSH-induced cAMP production in ovarian follicles

During the terminal part of their development, ovarian follicles become totally dependent on gonadotropin supply to pursue their growth and maturation. Both gonadotropins, follicle-stimulating hormone (FSH) and luteining hormone (LH), operate mainly through stimulatory G protein-coupled receptors, their signal being transduced by the activation of the enzyme adenylyl cyclase and the production of second-messenger cAMP. In this paper, we develop a mathematical model of the dynamics of the coupling between FSH receptor stimulation and cAMP synthesis. This model takes the form of a set of nonlinear, ordinary differential equations that describe the changes in the different states of FSH receptors (free, bound, phosphorylated, and internalized), coupling efficiency (activated adenylyl cyclase), and cAMP response. Classical analysis shows that, in the case of constant FSH signal input, the system converges to a unique, stable equilibrium state, whose properties are here investigated. The system also appears to be robust to nonconstant input. Particular attention is given to the influence of biologically relevant parameters on cAMP dynamics.

Relevance of an intensive postoperative follow-up after surgery for non-small cell lung cancer

BACKGROUND

Although a minimal follow-up with periodic clinic visits and chest radiographs is usually recommended after complete operation for non-small cell lung cancer, the ideal follow-up has not been defined yet. Objectives of this prospective study were to determine the feasibility of an intensive surveillance program and to analyze its influence on patient survival.

METHODS

Follow-up consisted of physical examination and chest roentgenogram every 3 months and fiberoptic bronchoscopy and thoracic computed tomographic scan with sections of the liver and adrenal glands every 6 months. Influence of patient and recurrence characteristics on survival from recurrence was successively analyzed using the log-rank test and a Cox model adjusted for treatment.

RESULTS

Among the 192 eligible patients, recurrence developed in 136 patients (71%) and was asymptomatic in 36 patients (26%). In 35 patients, recurrence was asymptomatic and detected by a scheduled procedure: thoracic computed tomographic scan in 10 (28%) patients and fiberoptic bronchoscopy in 10. Fifteen patients (43%) had a thoracic recurrence treated with curative intent. From the date of recurrence, 3-year survival was 13% in all patients and 31% in asymptomatic patients whose recurrence was detected by a scheduled procedure. Asymptomatic recurrences (p < 0.001), female sex (p < 0.001), performance status 2 or less (p = 0.01), and age 61 years or younger (p = 0.01) were shown to be significantly favorable prognostic factors.

CONCLUSIONS

This intensive follow-up is feasible and may improve survival by detecting recurrences after surgery for non-small cell lung cancer at an asymptomatic stage.

Fraction of proliferating cells in granulosa during terminal follicular development in high and low prolific sheep breeds

During terminal development of antral follicles, granulosa cells progressively lose their proliferative activity. Romanov (ovulation rate = 3) and Ile-de-France (ovulation rate = 1) breeds of sheep were compared for fractions of proliferating granulosa cells, determined by in vitro continuous [3H] thymidine labelling. In both breeds, the fraction of proliferating cells decreased with increasing follicular size according to a sigmoid-shaped curve. After linearization, the slope of the regression line was higher (in absolute value) in Romanov, compared to Ile-de-France ewes (p = 0.02). In vivo FSH treatment led to a decrease in the slope of the regression line in Romanov ewes only (p = 0.03). These results suggest that during terminal follicular development (1) the rate of cell cycle exit is higher in granulosa cells of Romanov, compared to lie-de-France follicles, and (2) Romanov granulosa cells are more responsive to exogenous FSH in term of proliferation. These mechanisms may underlie differential dynamics of follicular development in poly- and mono-ovulating breeds of sheep.

Which insemination results in fertilization when several are performed before ovulation?

The aim of the present study was to determine which artificial insemination results in fertilization when mares are inseminated several times before ovulation. Mares in oestrus were inseminated over 62 cycles with fresh semen at 48 h intervals from when a follicle > or =30 mm in diameter was detected until ovulation. The number of inseminations was limited to three. Three fertile stallions were used and a different stallion was used for each artificial insemination. The order of the three stallions was changed for each cycle. Embryos were collected between day 10 and day 12 after ovulation and paternity was checked using DNA typing. When two inseminations were performed per cycle, 14 of 17 embryos were the result of the insemination performed on days 2-4 before ovulation and three embryos were the result of the insemination performed on days 0-2. When three inseminations were performed, 1 of 6, 2 of 6 and 3 of 6 embryos resulted from the inseminations performed 4-6, 2-4 and 0-2 days before ovulation, respectively. Thus, 17 of 23 (74%) oocytes were not fertilized as a result of the insemination performed 0-2 days before ovulation. The mean interval between fertilization and ovulation in the mares from which embryos were recovered and tested (n=23) was 2.6 +/- 1.0 days. These results indicate that spermatozoa can remain viable in the genital tract of mares for at least 2.6 days.

Freezing of stallion semen: interactions among cooling treatments, semen extenders and stallions

In the present study, the interactions among stallions, semen extenders and cooling treatments before stallion semen samples were frozen were studied. In Expt 1, the effects of four cooling treatments and three semen extenders were investigated (11 stallions x four split ejaculates), whereas in Expt 2, the effects of two semen extenders, two egg yolk concentrations and two glycerol concentrations were investigated (six stallions x five split ejaculates). Sperm motility after thawing was evaluated. In Expt 1, the extender x cooling treatment interaction was significant. Centrifugation and addition of glycerol at 22 degrees C, followed by filling the straws at 4 degrees C and immediate freezing had detrimental effects in INRA82 + 2% (v/v) egg yolk + 2.5% (v/v) glycerol semen extender and in Gent semen extender compared with the same processes in Kenney + 4% (v/v) egg yolk + 3.6% (v/v) glycerol semen extender. The other cooling treatments, including moderate cooling of semen to 4 degrees C before freezing, resulted in higher sperm motility and had similar effects among treatments. Semen samples from some stallions appeared to withstand freezing more effectively after some cooling treatments than other treatments. Some stallion spermatozoa demonstrated higher motility in Kenney semen extender, whereas other semen samples had the same motility in all extenders. In Expt 2, the stallion x extender interaction was not significant. Increasing the glycerol concentrations from 2.5 to 3.5% (v/v) enhanced sperm motility in semen extenders containing 4% (v/v) egg yolk (INRA82 and Kenney). Increasing the egg yolk concentrations from 2 to 4% (v/v) in extenders containing 3.1-3.6% (v/v) glycerol improved sperm motility in Kenney semen extender only. These experiments demonstrate that there are possible differences in the ability of spermatozoa from different stallions to withstand different cooling treatments, but not necessarily in their tolerance to different semen extenders.

Optimal control of the cell dynamics in the granulosa of ovulatory follicles

The aim of this paper is to seek for the optimal cellular changes in the granulosa of ovarian follicles, leading to ovulation in minimal time. The granulosa cell population consists of proliferating, differentiated and apoptotic cells. Cell numbers are ruled by a system of differential equations, in which the control variables are the cell cycle exit and apoptosis rates. The conditions for ovulation are represented by three different constraints on the granulosa final state. We prove that the optimal strategy consists in applying permanently the minimal apoptosis rate and in switching the cell cycle exit rate from its minimal bound to its maximal one. We finally apply the optimal strategy on data providing the changes in the total cell number of ewe follicles during their terminal development.

Follicular growth and ovarian dynamics in mammals

General characteristics of female reproductive activity, such as seasonality, cyclicity and triggering of ovulation differ widely among mammals, but common mechanisms underlie ovarian function. In all mammals, follicles begin to grow from a pool of primordial follicles constituted early in life, continuously throughout the life of the female. Follicular development involves two phases. In a first phase (basal follicular growth), follicles grow slowly and follicular growth rate is tightly related to proliferation of granulosa cells. Basal follicular growth is mainly under the control of growth factors of paracrine origin. In these follicles, FSH may exert an indirect mitogenic effect on granulosa cells by enhancing expression of growth factors or growth factor receptors. In a second phase (terminal follicular growth), follicular growth is rapid and occurs by enlargement of the antrum. In addition, it is accompanied by important changes in differentiation of follicular cells. Terminal follicular development is strictly dependent on gonadotrophins. FSH plays determinant roles in enhancing granulosa cell differentiation and survival. These actions are mediated or modulated in an important way by paracrine factors, particularly steroids and growth factors. LH stimulates steroidogenesis in theca cells and sustains terminal maturation of granulosa cells in preovulatory follicles. Follicular growth, atresia and ovulation are accompanied by important tissue remodelling processes, which are under the fine control of proteinases and inhibitors of proteinases. In particular matrix metalloproteinases and their inhibitors are probably involved in the control of rapid terminal follicular growth and regression of atretic follicles as well as in follicular rupture at ovulation.

Tetrasomy 8 in a patient with acute nonlymphocytic leukemia: a metaphase and interphase study with fluorescence in situ hybridization

Tetrasomy 8 constitutes a relatively rare recurring chromosome defect in myeloid disorders. The patient reported here, a 71-year-old man, presented with tetrasomy 8 as the sole chromosome abnormality associated with an acute nonlymphocytic leukemia of the M2 type. He failed to respond to chemotherapy and died one year after diagnosis. Following conventional cytogenetics and fluorescence in situ hybridization (FISH) with a centromeric probe specific for chromosome 8, tetrasomy 8 was detected in 61% of the metaphases analyzed and trisomy 8 in 39%. FISH analysis of interphase nuclei confirmed the existence of tetrasomic (35%) and trisomic cells (56%) and revealed a number of cells with two chromosomes 8 (8%). This normal population may represent lymphocytes or myeloid cells that escaped conventional analysis due to their inability to divide or to the small number of metaphases available. The relatively higher proportion of tetrasomic cells in metaphase compared with interphase may be attributed to a proliferative advantage of tetrasomic cells in vitro or to the longer duration of their cell cycle. The simultaneous presence of trisomic and tetrasomic cells confirms the hypothesis of a clonal relationship between trisomy 8 and tetrasomy 8. Our case brings further evidence to the specificity of tetrasomy 8 to myeloid disorders and to the association of this chromosome abnormality with a relatively poor prognosis. However, new patients must be studied to further delineate this cytogenetic entity.

[Heart rate fluctuations in the horse at rest: (2) Biological variation factors related to behavioural profile]

Variability of heart rate was analysed within a sample of 30 horses in order to determine the influence of factors (animal, age, sex and breed) associated with different behavioural patterns. The heart rate fluctuations were analysed by computing the power spectral density of a series of heartbeat intervals. A generalized linear model was used to compare the spectra and to reveal the effect of each factor: animal age, sex and breed. The scale and shape of spectral densities were significantly different between animals. This individual variability was partly explained by the sex and age effects while the breed effect had only a weak influence. Young horses and mares exhibited a greater heart rate fluctuation which may be related to their higher emotionality.

[Heart rate fluctuations in the horse at rest: (1) Investigation of heart rate changes by spectrum analysis]

The heart rate fluctuations at rest were studied in order to explore the emotionality of the horses by isolating the influence of the autonomic control. This paper presents a method of spectral analysis which was used to analyse the heart rate variability in the frequency domain. The heartbeat intervals were recorded during 1 h and a series of 1,024 heartbeats was extracted to compute a power spectrum of density. This was obtained by calculating the Fourier transform of the autocorrelation function of the series. This spectral analysis was applied to heart rate recordings in order to illustrate its sensitivity. The normal heart rate fluctuations at rest were compared with those obtained after atropine and atropine+adrenaline injections. The normal power spectrum revealed several low frequency components (< 0.1 cycle/beat). The atropine injection reduced heart rate variability while the atropine+adrenaline injection increased the power of low frequency fluctuations.

[Cerebral protection by retrograde perfusion in the treatment of acute aortic dissection]

Four consecutive patients underwent resection and graft replacement of ascending aorta or aortic arch for acute dissection. Retrograde cerebral perfusion (RCP) was used during circulatory arrest. RCP at 15 degrees C was administered through the superior vena cava. Duration of cerebral ischaemia and cardiopulmonary bypass averaged 33 and 156 minutes respectively. Retrograde perfusion flow was regulated from 100 to 800 ml/minute to maintain an internal jugular vein pressure of about 25 cm H2O. All patients survived. Three patients awoke neurologically intact. Minor neurological disturbance was found in 1 patient, he was discharged from hospital at day 11 without any detectable neurological deficit. This technique was attractive because it provided a dry operative field unencumbered by perfusion cannulas or clamps, facilitated construction of a more secure distal anastomosis, and avoided the risk of further injury resulting from the aortic cross clamp. It seems that RCP allows longer circulatory arrest time.

Two-dimensional polyacrylamide gel electrophoresis analysis of cryoglobulins and identification of an IgM-associated peptide

The clonality of immunoglobulins (Igs) in cryoprecipitates (n = 41) was studied by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Our series included 24 cryoglobulins characterized by immunofixation electrophoresis (IF), 12 'trace amount' cryoglobulins, defined by a protein content in the precipitate of less than 0.05 mg/ml of serum, and five cryoglobulins of undetermined protein composition by IF. 2-D PAGE analysis showed polyclonal IgG associated either with monoclonal Igs (type II cryoglobulins; n = 14) or with polyclonal IgM (type III cryoglobulins; n = 14). In ten cryoprecipitates (two 'trace amount' cryoglobulins as well as seven of 19 type II and as one of five type III cryoglobulins by IF) polyclonal IgG were associated with a mixture of polyclonal and monoclonal IgM. These cryoglobulins were tentatively named type II-III cryoglobulins. A monoclonal IgM was observed in one cryoprecipitate (type I cryoglobulins). Two cryoglobulins presented unexpected 2-D patterns, characterized by the presence of oligoclonal IgM, with trace amounts of Igs of different isotypes (tentatively named type II-III(variant) cryoglobulins). A peptide of 44 kDa with a pI of 5.45 was observed in all cryoglobulins containing IgM (n = 40). This peptide was also present in purified monoclonal or polyclonal IgM fractions. N-terminal microsequencing (12 amino acid residues) revealed that this IgM-associated peptide was an unknown protein. Our results highlight the role of 2-D PAGE as an aid in the analysis of cryoglobulins.

Isolation of specific DNA fragments of Mycobacterium avium and their possible use in diagnosis

We cloned and sequenced two DNA fragments (DT1 and DT6) from Mycobacterium avium serotype 2 for use in the identification of members of the M. avium-M. intracellulare complex (MAC). Reference strains of MAC belonging to serovars 1 to 28 were examined by using these DNA fragments as probes. The study revealed that the DT6 probe hybridized with DNAs from M. avium strains (serovars 1 to 6, 8 to 11, and 21), while the DT1 probe hybridized with DNAs from serovars 2, 3, 7, 12 to 20, and 23 to 25. DT1- and DT6-derived oligonucleotides were selected for use as primers in a polymerase chain reaction test. Amplification of the DT1 and DT6 sequences may provide the basis for a rapid and reliable assay for the detection of mycobacteria belonging to MAC.

Pulsed field gel electrophoresis of representatives of Mycobacterium tuberculosis and Mycobacterium bovis BCG strains

Using field inversion gel electrophoresis (FIGE), different Mycobacterium tuberculosis strains, such as phage prototypes, exhibit different DNA restriction patterns which are easy to compare. Virulent and avirulent variants of M. tuberculosis H37, as well as daughter strains of M. bovis BCG, display characteristic DNA profiles. BCG strains isolated from suppurative adenitis following vaccination of French patients showed patterns identical to the BCG Pasteur strain used for vaccination. These results demonstrate that FIGE of DNA restriction fragments generated by DraI represents a suitable technique for the analysis of mycobacteria at a genomic level. The DraI profiles allow the differentiation and precise identification of the BCG Pasteur, Glaxo, Russian and Japanese strains.

Clonality of cold agglutinins in patients with hemolytic anemia: an analysis by high-resolution two-dimensional gel electrophoresis

High-resolution two-dimensional gel electrophoresis (2-DGE) was used to analyse plasma samples and partially purified cold agglutinins (CA) obtained from two selected patients. Both presented an acute hemolytic anemia with CA of high thermal amplitude, normal immunoglobulin levels, no detectable paraproteinemia, and no clinical evidence of a malignant B-cell disorder. The electrophoretograms of their plasma showed evident alternations of the "normal" protein profile, which were directly related to hemolysis (absence of the spots of haptoglobin and in one case of those of hemopexin), but no monoclonal gammopathy. The electrophoretograms of their purified CA revealed two clearly different spot patterns respectively corresponding to a monoclonal IgM and to polyclonal IgM. These results show that the clonality of CA associated with hemolytic anemia can be easily determined by 2-DGE. This technique may be very useful to discriminate chronic cold agglutinin disease in the early phase from "parainfectious" CA.

Genotypic and phenotypic evidence of T-cell leukemia in a patient successfully treated by interferon-alpha for typical hairy cell leukemia

A 53-year-old man was diagnosed to have typical hairy cell leukemia. Immunophenotyping of frozen splenic tissue showed clonality of hairy cells for mu lambda, confirmed by the corresponding immunoglobulin gene rearrangements. The patient was successfully treated with interferon-alpha (IF-alpha). In the fifth year of treatment with IF-alpha the morphology of peripheral blood mononuclear cells (PBMC) and of bone marrow infiltration changed with the appearance of numerous small to intermediate shaped lymphocytes of a T-helper phenotype. Frank leukemia, resistant to IF-alpha treatment and ultimately aggressive chemotherapy, developed. Emergence of this second clonal disease was confirmed by rearrangement studies performed on PBMC; rearrangements of both alleles of the TCR beta were identified, whereas the JH and lambda IVS genes were in germline configuration. The outgrowth of a second, malignant T-cell clone paralleled by the disappearance (down-regulation?) of the initial B-cell clone while under cytokine treatment is consistent with the possibility that IF-alpha favoured the emergence of this second clone.

[Achondrogenesis. Ultrasonic diagnosis and clinical and anatomopathologic comparison]

The authors report two cases of achondrogenesis, the first of which was diagnosed in utero. Ultrasonographic abnormalities suggested the diagnosis, which was confirmed radiographically. The diagnosis of achondrogenesis in utero made it possible to avoid a Cesarian. It is always difficult to extract the malformed fetus. The histopathology findings make it possible to codify this rare type of congenital and lethal chondrodysplasia. Achondrogenesis is probably inherited in a recessive and autosomic fashion.

[The treatment of acute lymphatic leukemia in adults: pilot project with intensive early therapy without a maintenance phase]

Acute lymphoblastic leukemia (ALL) is conventionally treated in three phases: remission induction, consolidation and maintenance. In adults initial remission rates of nearly 80% can be achieved. The 3 to 5 year leukemia free survival is 20 to 40%. Most relapses occur during maintenance, despite continuous therapy for 2 to 3 years. The value of maintenance therapy following intensive induction in adults is not documented. In this pilot study we treated 34 patients with ALL in five Swiss centers between 1986 and 1989 with intensive induction/consolidation therapy alone. Three induction/consolidation courses were applied: course I, 43 days, consisting of daunomycin, vincristine, prednisone, methotrexate, L-asparaginase and intrathecal CNS prophylaxis; course II, 6 days, consisting of high dose cytosine arabinoside and VP-16; course III, three non randomized arms, either allogeneic or autologous bone marrow transplantation (BMT) or high dose cyclophosphamide and repeated intrathecal therapy alone. 32 patients (94%) reached complete remission (CR): 24 after course I (71%), 7 after course II (cumulative 91%) and one after course III only (cumulative 94%). 3 patients had early, relapses before course III, 3 died of infection, and 2 of graft-versus-host disease. One patient had refractory leukemia in all three courses. 26 patients (76%) were in CR after completion of therapy. 16 relapsed within 1 to 17 months (median 5). 10 patients are free of disease after 10 to 44 months (median 24): 5 had had allogeneic BMT, 3 autologous BMT and 2 cyclophosphamide in course III.(ABSTRACT TRUNCATED AT 250 WORDS)

[Abrikossoff's tumor with bronchial localization. Contribution of x-ray computed tomography in a new case]

The authors present a case of Abrikossoff's tumor located in the segmental bronchus and detected on a systematic chest radiography, diagnosed during an endoscopy is reported. The CT study specified the tumoral extension. Bronchial distal affections is very rare. A confrontation with the anatomopathological data allowed a better understanding scanographic aspect.

[Monoclonal gammopathies of undetermined significance called "MGUS"]

While the discovery of a monoclonal gammopathy in the blood of a patient sometimes leads to the diagnosis of multiple myeloma, immunocytoma or other B-cell lymphoproliferative syndromes, "secondary" monoclonal dysproteinemia is seldom considered. In most cases "monoclonal gammopathy of undetermined significance" (MGUS) is diagnosed. After ten years about 25% of these cases evolve to true multiple myeloma or Waldenström's disease. Other MGUS usually remain asymptomatic, though sometimes a complication such as amyloidosis or cryoglobulinemia may occur as a result of the "perverse" effect of the monoclonal protein. Some cases are described.

[Propofol and thoracic surgery]

20 patients undergoing thoracic surgery were studied. Before anaesthesia either a catheter was placed in the intercostal space, at the same level as the thoracotomy (16 patients) or an epidural catheter was inserted if there was a contraindication of intercostal blockade (4 patients). Marcaine 0.5--was injected. Anaesthesia was induced with propofol 2.5 mg.kg-1, vecuronium 0.1 mg.kg-1, dextromoramide 50 mcg.kg-1. It was maintained with propofol 9 mg.kg-1.h-1 for 30 mn, then 4.5 mg.kg-1.h-1 for following hours (by a syringe pump) and vecuronium 0.1 mg.kg-1.h-1. Cardio vascular effects were studied only in the 16 patients with intercostal blockade: during induction bradycardia in 3 patients, and systolic arterial pressure (S.A.P.) decrease of 30% in 8 patients were observed. After the incision, heart rate and S.A.P. became steady. The average duration of anaesthesia was 214 min +/- 74. The time from the end of propofol infusion to the moment of extubation was 15.4 min +/- 33 and the time to recover all mental faculties was 46 mn +/- 11. 30 min after the end of anaesthesia the maxima minute ventilation was equal to the post operative value at 48 H. Propofol anaesthesia allows a fast awakening, without cumulative effects.

Studies on clofazimine-resistance in mycobacteria: is the inability to isolate drug-resistance mutants related to its mode of action?

This study showed that clofazimine was not radiomimetic, it was not a mutagenic compound, it was not an inducer of prophage-lambda, and it did not eliminate plasmids from appropriate host bacteria. The drug caused an effective inhibition of the growth of Mycobacterium aurum, and also inhibited the growth cycle of the mycobacteriophage D29. Cross-resistance between clofazimine, streptomycin and rifampicin could not be demonstrated. Drug-resistance mutants towards clofazimine could not be isolated, and it was found that the existing clofazimine-resistant strains of Mycobacterium tuberculosis were rather susceptible organisms requiring clofazimine in their growth medium to maintain their drug-resistance. Ultrastructural studies showed that clofazimine did not act by cell wall lysis, nor did it act on bacterial ribosomes. Higher concentrations of the drug resulted in bacterial plasmolysis. These findings are discussed in the light of its known properties and proposed mode of action.

Structure of the cell envelope of Mycobacterium avium

In this report the cell wall of Mycobacterium avium is shown as a triple-layered structure where the outermost layer was stained by the ruthenium red staining for polysaccharides. The outermost layer hindered the diffusion of chemotherapeutic agents across the wall thus causing multiple drug-resistance by exclusion. The concerted electron microscopy and chemical analysis of chloroform-methanol and Triton X-100 extracts indicated that the outer layer was made of diverse amphiphil glycolipids (mycosides C, glycolipids, peptidolipids, phospholipids) that formed a matrix in which proteins were embedded. The examination of a spontaneous rough mutant indicated that mutations blocking the synthesis of one or several of the amphiphils must leave unsubstituted mycolic acid residues, thus causing surface hydrophobicity and roughness. Judging from our data, a model describing the overall cell envelope of M. avium was proposed. From the comparative analysis of M. avium, its spontaneous rough mutant, and its spheroplasts, some of the functions of the outermost layer were disclosed.

Action of colistin (polymyxin E) on the lytic cycle of the mycobacteriophage D29 in Mycobacterium tuberculosis

The antibiotic colistin (polymyxin E) inhibited the lytic cycle of the mycobacteriophage D29 in the tubercle bacilli, but not the D29 adsorption. The protein and nucleic acid synthesis in D29-infected bacteria were not affected significantly. The inhibitory activity was reversed by washing off the antibiotic, and by addition of Ca++, but not in media made iso-osmotic by addition of NaCl or sucrose. Transmission electron microscopy revealed an asymmetric to symmetric transition in the staining profile of the cytoplasmic membrane. Though no mature phage particles were ever observed in colistin-treated, D29-infected tubercle bacilli, loosely arranged aggregates resembling phage proheads were occasionally found. Judging from the above data, it was concluded that colistin inhibited D29 lytic cycle by causing molecular displacements in the inner leaflet of the cytoplasmic membrane, and consequently, the binding sites for D29 structural proteins were not available.

[Treatment of multiple myeloma]

Multiple myeloma comprises widely varying clinical varieties of a more or less evolutive character. Establishment of an effective therapeutic plan requires inter alia an analytical study of tumor mass (stages) and cytokinetics. Thus, "indolent", "slow" or "aggressive" myelomas have been reported. 19 consecutive symptomatic patients (12 with stage II, 6 with stage III) have been treated, with overall 5-year survival of 42%. In the light of these observations and the recent literature it appears essential to adopt a flexible therapeutic approach which allows a rapid switch from simple chemotherapy to heavy polychemotherapy when necessary, or postponement of treatment or halting of chemotherapy under selected conditions.