Otitis media with effusion in nasal polyposis and outcomes following surgery: A longitudinal observational study

OBJECTIVE

In patients with nasal polyposis (NP), otitis media with effusion (OME) seems to be a marker of severity of the inflammatory process occurring in those patients. The aim was to assess whether OME could represent a marker of resistance to the surgical treatment of NP.

DESIGN

Longitudinal observational cohort study including patients between January 1991 and January 2017. Mean follow-up was 7.4 years.

SETTING

Tertiary-care hospital centre.

PARTICIPANTS

Patients with NP who underwent surgery (radical bilateral sphenoethmoidectomy).

MAIN OUTCOME MEASURES

Four outcomes reflecting resistance to the surgical treatment: a clinical score of rhinologic symptoms, the mean number of systemic corticosteroids treatment per year, the recurrence rate of polyps and the rate of reoperation.

RESULTS

A total of 266 patients were included (63.9% of men, mean age 48 years). In multivariate linear mixed-effects regression, when compared to patients without OME, patients with OME presented a similar clinical score of symptoms (coefficient 0.09, 95% confidence interval (CI) -0.25 to 0.06, P-value = 0.24) and a borderline higher mean number of systemic corticosteroids treatments per year (coefficient 0.11, 95% CI 0.003-0.23, P-value = 0.04). In multivariate Cox regression analyses, patients with OME had a similar reoperation rate than patients without OME (hazard ratio (HR) 0.29, 95% CI 0.06-1.50) and a similar recurrence rate of polyps (HR 0.59, 95% CI 0.23-1.53).

CONCLUSION

In patients with NP, OME is not a marker of surgical resistance. Those patients should be managed similarly than patients without, and similar outcomes following surgery should be expected.

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models

Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

Electrophysiological exploration of hearing

Electrophysiologic hearing tests have been developed since the 1960s to determine hearing thresholds objectively. They are now implemented in newborn hearing screening. While they determine thresholds, interpretation requires subjective pure-tone and speech audiometry to determine the type of hearing loss. Each examination tests a different anatomic region, enabling the auditory system to be explored from the organ of Corti to the auditory cortex. Thus, the various objective audiometric examinations are complementary.

Short Communication: Birdsfoot trefoil as a preventative treatment for gastrointestinal nematodes in pastured dairy heifers

Shepley, E., Vasseur, E., Bergeron, R., Villeneuve, A. and Lachance, S. 2015. Short Communication: Birdsfoot trefoil as a preventative treatment for gastrointestinal nematodes in pastured dairy heifers. Can. J. Anim. Sci. 95: 533–537. Bioactive forages, such as birdsfoot trefoil, may serve as an alternative to anthelmintic drugs in pastured dairy heifers. Differences in parasite burden and growth were examined between eight treatment heifers fed a birdsfoot trefoil mixture and nine control heifer fed alfalfa silage 45-min per day for 12 wk. A significant 3.8- to 9.4-fold reduction in fecal egg counts was observed for treatment heifers at weeks 5, 9, 11 and 12. No treatment effect was found for weight gain. Our results suggest that birdsfoot trefoil may reduce parasite fecal egg counts in pastured dairy heifers without detrimental impact on growth.

The effect of the transducers on paediatric thresholds estimated with auditory steady-state responses

The objective of this study was to investigate the usefulness of auditory steady-state responses (ASSRs) for estimating hearing thresholds in young children, compared with behavioural thresholds. The second objective was to investigate ASSR thresholds obtained with insert earphones versus supra-aural headphones to determine which transducer produces ASSR thresholds most similar to behavioural thresholds measured with supra-aural headphones. This retrospective study included 29 participants (58 ears): 12 children (24 ears) in the insert group and 17 children (34 ears) in the supra-aural group. No general anaesthesia was used. For both groups, there was a strong correlation between behavioural and ASSR thresholds, with a stronger correlation for the insert group. When behavioural thresholds are difficult to obtain, ASSR may be a useful objective measure that can be combined with other audiometric procedures to estimate hearing thresholds and to determine appropriate auditory rehabilitation approaches.

Widely tunable mid-infrared generation via frequency conversion in semiconductor waveguides

Phase matching in a multilayer AlGaAs waveguide is used to generate mid-IR (7.5-8.5 μm) light through difference frequency generation (DFG) between a 1550 nm pump and 1950 nm signal. This represents the longest wavelength generated through DFG in a 2D waveguide mode in a semiconductor waveguide. It was produced with an efficiency of 1.2×10(-4) %/W in a 1 mm long sample. The process is shown to be tunable across >2 μm through appropriate tuning of the input pump and signal wavelengths and/or waveguide geometry, and is therefore a viable platform for monolithic, tunable, mid-IR sources.

Field study of the efficacy of halofuginone and decoquinate in the treatment of cryptosporidiosis in veal calves

Ninety, seven- to 10-day-old calves were allocated to three groups of 30 and treated daily for seven days with either 100 microg/kg halofuginone hydrobromide or 2.5 mg/kg decoquinate orally or left untreated as controls. The levels of diarrhoea and dehydration were monitored daily for 28 days from the first day of treatment (day 0) and samples of faeces were collected on days 0, 7, 14, 21 and 28, to quantify the excretion of Cryptosporidium parvum oocysts. The calves were weighed on days 3 and 28. The treatments had no effect on the levels of diarrhoea or dehydration, the proportions of diarrhoeic calves or the proportions of calves shedding oocysts. However, unlike decoquinate, halofuginone significantly reduced the excretion of oocysts on day 7 (P<0.0001), and decoquinate increased the average daily weight gain of the calves (P=0.049).

GermOnline, a cross-species community knowledgebase on germ cell differentiation

GermOnline provides information and microarray expression data for genes involved in mitosis and meiosis, gamete formation and germ line development across species. The database has been developed, and is being curated and updated, by life scientists in cooperation with bioinformaticists. Information is contributed through an online form using free text, images and the controlled vocabulary developed by the GeneOntology Consortium. Authors provide up to three references in support of their contribution. The database is governed by an international board of scientists to ensure a standardized data format and the highest quality of GermOnline's information content. Release 2.0 provides exclusive access to microarray expression data from Saccharomyces cerevisiae and Rattus norvegicus, as well as curated information on approximately 700 genes from various organisms. The locus report pages include links to external databases that contain relevant annotation, microarray expression and proteome data. Conversely, the Saccharomyces Genome Database (SGD), S.cerevisiae GeneDB and Swiss-Prot link to the budding yeast section of GermOnline from their respective locus pages. GermOnline, a fully operational prototype subject-oriented knowledgebase designed for community annotation and array data visualization, is accessible at http://www.germonline.org. The target audience includes researchers who work on mitotic cell division, meiosis, gametogenesis, germ line development, human reproductive health and comparative genomics.

Septic peritonitis due to colonic perforation associated with aberrant migration of a Gasterophilus intestinalis larva in a horse

An adult quarter horse mare was presented with acute colic and fever. Physical examination and abdominocentesis showed septic peritonitis, and the mare was euthanatized. Necropsy and histopathologic examination revealed a focal partial perforation of the right ventral colon, which contained a single bot fly larva, identified as a third-instar larva of Gasterophilus intestinalis. This larva was embedded deep within the muscularis and the submucosa. Although bot fly larvae are known to attach to aberrant sites within the digestive tract, this is the first known report of deep penetration of the colon by a gasterophilus larva, with the resulting leakage of intestinal content leading to septic peritonitis.

Failure of dogs to shed oocysts after being fed bovine fetuses naturally infected by Neospora caninum

Neospora caninum is a protozoan that causes abortion in cattle. The dog has recently been identified as a definitive host for N. caninum. To verify if bovine fetuses can infect dogs, nine 2-4-month-old dogs were fed bovine fetuses naturally infected by N. caninum. None of the dogs excreted oocysts, seroconverted, had clinical signs or lesions compatible with N. caninum infection. Additional studies will be necessary to determine the natural mode of infection of dogs by N. caninum.

Evaluation of a strategic deworming program in dairy heifers in Quebec based on the use of moxidectin, an endectocide with a long persistency

Two different deworming strategies based on the use of moxidectin, a broad spectrum endectocide with persistency against Ostertagia ostertagi, were evaluated in grazing dairy heifers. Eighty-four heifers unexposed to parasitic infection were randomly allocated to 3 different groups: untreated (Group 1), treated at 3 and 10 weeks after turnout with 0.5 mg/kg/body weight (BW) of topical moxidectin (Group 2), or treated at turnout and 10 weeks later with 0.5 mg/kg/BW of topical moxidectin (Group 3). The heifers were turned out on June 6 (Day 0) to a naturally contaminated pasture divided into 3 sections by an electrical fence. Each group of heifers was put on a different section of pasture. The trial ended when they were housed on October 29 (Day 143). The results of this experiment confirmed the beneficial effect of 2 strategic treatments with moxidectin pour-on under field conditions in Quebec. The parasitological parameters showed a statistical difference in terms of mean fecal egg counts between treated and control groups (ANOVA, P < or = 0.006). After turnout, pasture larval counts were consistently higher for Group 1 compared with counts for Group 2 or 3. All heifer groups gained weight during the trial period, but the weight gain profile of both treated groups was significantly higher than that of the untreated controls (ANOVA, P < 0.03). During the trial period, Group 2 and Group 3 gained 77.7 kg BW and 73.2 kg BW, respectively, while Group 1 gained only 57.9 kg BW, despite the fact that heifers of Group 1 received a greater quantity of supplementary feed while on pasture.

Optical field-induced mass transport in As2S3 chalcogenide glasses

We report the observation of a photorefractivelike nonlinearity responsible for the formation of giant relief modulations in amorphous semiconductor glasses. The photoinduced softening of the matrix, formation of defects with enhanced polarizability, and their drift under the optical field gradient force is believed to be the origin of the mass transport.

Glucocorticoids decrease endothelin-A- and -B-receptor expression in the kidney

Glucocorticoids play an important role in circulatory homeostasis and in excess they cause hypertension. These corticosteroids affect the expression of many genes involved in blood pressure control including preproendothelin-1 (PPET-1), the precursor of endothelin-1 (ET-1), a potent vasoactive peptide. We have previously shown that glucocorticoids increase PPET-1 mRNA levels in rat aorta. Moreover, they also affect ET(A)- and ET(B)-receptor expression in various in vitro and in vivo situations. Both ET-1 and glucocorticoids exert direct effects in the kidney and are involved in vascular resistance and sodium balance. We therefore sought to determine the effects of glucocorticoids on renal PPET-1, ET(A)- and ET(B)-receptor expression in an animal model of glucocorticoid-induced hypertension. Wistar rats were given 2.5 mg/l of dexamethasone, a glucocorticoid agonist, in their drinking water for 1 or 5 days. Our data reveal that dexamethasone administration increases systolic blood pressure (SBP) in rats. SBP rose from 120 +/- 3 to 139 +/- 4 and 150 +/- 5 mmHg after 1 and 5 days treatments, respectively (p < 0.05). Furthermore, dexamethasone administration decreased ET(A) and ET(B)-receptor expression in the rat kidney. This effect was observed after 1 day of dexamethasone treatment with ET(A) and ET(B)-receptor mRNA levels decreasing to 83 +/- 2% and 80 +/- 5% of control values. respectively (p < 0.01). Both ET(A)- and ET(B)-receptor mRNA levels further declined to 67 +/- 3 and 65 +/- 6% of control values after 5 days of dexamethasone treatment, respectively (p < 0.001). Interestingly, kidney PPET-1 expression was not affected by dexamethasone administration. Our results suggest a contribution of renal ET receptors in glucocorticoid actions on blood pressure control.

Toward soliton emission in asymmetric GaAs/AlGaAs multiple-quantum-well waveguide structures below the half-bandgap

We report what is to our knowledge the first experimental evidence of nonlinear beam displacement in a strip-loaded GaAs/AlGaAs multiple-quantum-well waveguide with an asymmetric, nonlinear cladding. An intensity-dependent spatial displacement of ~2 mum was observed for the guided mode at a wavelength of 1.55 mum. Numerical simulations that correspond to the experiment are also presented. The device has the potential of providing a soliton-emission-based, ultrafast all-optical switch.

Vertical and horizontal transmission of Neospora caninum in dairy herds in Québec

Neospora caninum is an important cause of abortion in dairy cattle. The objective of this observational study was to estimate the rate of vertical transmission of N. caninum in dairy herds in Québec and to investigate horizontal transmission in the same herds. The genealogy of cows from 23 dairy herds were examined. Prevalence of seropositive animals in herds studied varied from 4.3% to 61.8% (average, 21.9%). The overall rate of vertical transmission was estimated to be 44.4%, varying from 0% to 85.7%. Seven cases of horizontal transmission were identified in 6 of the 23 herds studied. Estimated vertical transmission rate varied from herd to herd, but appeared to be higher in herds with a high prevalence of seropositive animals. Although horizontal transmission was identified in 6 herds, it does not appear to be the major route of infection for N. caninum.

Adenosine induces cyclic-AMP formation and inhibits endothelin-1 production/secretion in guinea-pig tracheal epithelial cells through A(2B) adenosine receptors

1. The adenosine receptor subtype mediating adenosine 3' : 5'-cyclic monophosphate (cyclic AMP) formation and the effect of its activation on endothelin-1 (ET-1) secretion were studied in primary cultures of tracheal epithelial cells. 2. Adenosine analogues showed the following rank order of potency (pD(2) value) and intrinsic activity on the generation of cyclic AMP by tracheal epithelial cells: 5'-N-ethylcarboxyamidoadenosine (NECA, A(1)/A(2A)/A(2B), pD(2): 5.44+/-0.16)>adenosine (ADO, non selective, pD(2): 4.99+/-0. 09; 71+/-9% of NECA response) >/=2-Cl-adenosine (2CADO, non selective, pD(2): 4.72+/-0.14; 65+/-9% of NECA response)>>>CGS21680 (A(2A); inactive at up to 100 microM). 3. Cyclic AMP formation stimulated by NECA in guinea-pig tracheal epithelial cells was inhibited by adenosine receptor antagonist with the following order of apparent affinity (pA(2) value): Xanthine amine congeners (XAC, A(2A)/A(2B), 7.89+/-0.22)>CGS15943 (A(2A)/A(2B), 7.24+/-0. 26)>ZM241385 (A(2A), 6.69+/-0.14)>DPCPX (A(1), 6.51+/-0. 14)>3n-propylxanthine (weak A(2B), 4.30+/-0.10). This rank order of potency is typical for A(2B)-adenosine receptor. 4. Adenosine decreased basal and LPS-stimulated irET production in a concentration-dependent manner. Moreover, NECA but not CGS21680 inhibited LPS-induced irET production. 5. The inhibitory effect of NECA on LPS-induced irET production was reversed by XAC (pA(2)=8.84+/-0. 12) and DPCPX (pA(2)=8.10+/-0.22). 6. These results suggested that adenosine increased cyclic AMP formation and inhibited irET production/secretion by guinea-pig tracheal epithelial cells through the activation of a functional adenosine receptor that is most likely the A(2B) subtype. This adenosine receptor may be involved in the regulation of the level of ET-1 production/secretion by guinea-pig tracheal epithelial cells in physiological as well as in pathophysiological conditions.

Genome-wide search for linkage of bipolar affective disorders in a very large pedigree derived from a homogeneous population in quebec points to a locus of major effect on chromosome 12q23-q24

We completed a genome-wide scan for susceptibility loci for bipolar affective disorders in families derived from a rather homogeneous population in the Province of Québec. The genetic homogeneity of this population stems from the migration of founding families into this relatively isolated area of Québec in the 1830s. A possible founder effect, combined with a prevalence of very large families, makes this population ideal for linkage studies. Genealogies for probands can be readily constructed from a population database of acts of baptism and marriage from the early 1830s up to the present time (the BALSAC register). We chose probands with a DSM III diagnosis of bipolar affective disorder and who may be grouped within large families having genealogical origins with the founding population of the Saguenay-Lac-St-Jean area. Living members (n approximately 120) of a very large pedigree were interviewed using the Structured Clinical Interview for DSM III (SCID I), SCID II, and with a family history questionnaire. A diagnostic panel evaluated multisource information (interview, medical records, family history) and pronounced best-estimate consensus diagnoses on all family members. Linkage, SimAPM, SimIBD, and sib-pair analyses have been performed with 332 microsatellite probes covering the entire genome at an average spacing of 11 cM. GENEHUNTER and haplotype analyses were performed on regions of interest. Analysis of a second large pedigree in the same regions of interest permitted confirmation of presumed linkages found in the region of chromosome 12q23-q24.

Nonevaluative social support reduces cardiovascular reactivity in young women during acutely stressful performance situations

We tested whether the presence of a stranger reduces cardiovascular responses during stressful tasks if the evaluation potential of the stranger is minimized and whether cardiovascular responses are affected by the quality of support in a friendship. Undergraduate women performed stressful tasks in one of three conditions: Alone, with a same-sex Stranger, or with a same-sex best Friend. The stranger and friend could not hear participants' responses. Alone women had the greatest increases in SBP and HR while women in the Stranger and Friend conditions did not differ in their responses. In the Friend condition, HR responses were smallest in women who were highly satisfied with the support that they generally received from their friend. We conclude that the presence of a nonevaluative friend or stranger can reduce cardiovascular responses and that the quality of supportive ties modulates the impact of those ties on responses to stress.

Respiratory nematodiases in raptors in Quebec

This is a retrospective study on wild raptors submitted to the Université de Montréal (Quebec, Canada) from 1989 to 1996. Cyathostoma spp. (Nematoda: Syngamidae) adults and/or eggs were found in air sacs, lungs, bronchi, and trachea of 12 raptors (Falconiformes and Strigiformes) from Quebec, Canada, belonging to eight different species, five of which are first host records for this parasite: barred owl (Strix varia), snowy owl (Nyctea scandiaca), northern harrier (Circus cyaneus), northern goshawk (Accipiter gentilis), and broad-winged hawk (Buteo platypterus). The infection was considered fatal in four birds, while no significant clinical signs were observed in the other cases. Major pathologic changes included diffuse pyogranulomatous air sacculitis, pneumonia, and bronchitis. A few unidentified larval nematodes embedded in a granuloma were found in the lungs of an additional Coopers' hawk (Accipiter cooperii); they were not considered clinically significant. A dead nematode, surrounded by necrotic inflammatory cells, was found in the air sac of a northern goshawk. The presence of nematodes in air sacs or lungs should be considered in wild raptors demonstrating respiratory problems.

Glucocorticoids increase preproendothelin-1 expression in rat aorta

Glucocorticoids play an important role in circulatory homeostasis. They modulate peripheral resistance by their direct action on blood vessels. We have previously shown that glucocorticoids increase preproendothelin-1 gene transcription rate in vascular smooth muscle cells (Morin C et al. 1998, BBRC 244:583). Endothelin-1 is a potent vasoactive peptide involved in the maintenance of vascular tone as well as in pathophysiological states. In this report we show that glucocorticoids increase preproendothelin-1 expression in rat aorta. The rise in preproendothelin-1 steady state mRNA level is dose-dependent with a maximal 2.3-fold stimulation 8 hours following a 0.35 and a 2.5 mg/kg dexamethasone injection. A lower dose of dexamethasone (0.13 mg/kg) also increased preproendothelin-1 expression in rat aorta. Since endothelin-1 levels are regulated at the transcriptional step, the increase in mRNA is likely to be paralleled by increased protein synthesis and vasoconstrictor action. Moreover, systolic blood pressure was significantly elevated in rats who received the 0.35 and 2.5 mg/kg doses of dexamethasone. Together, our results strongly suggest that the increase in preproendothelin-1 expression by glucocorticoids contributes to the regulatory action of these corticosteroids on blood pressure in health and disease.

Soliton-emitting AlGaAs waveguide

Simulations of soliton emission and propagation in a linear AlGaAs waveguide with one nonlinear cladding are presented. The device, which has realistic parameters, operates below half the bandgap and emits light into the cladding for a given input power. The use of selective disordering of the MQW guiding layer to realize the linear/nonlinear sections is discussed.

Evaluation of the protective efficacy of doramectin against sucking lice of cattle

The protective efficacy of doramectin against sucking lice was evaluated under natural challenge conditions in Canada. Two studies with a similar experimental design were conducted in sequence. In each study, two groups of louse-free cattle received either doramectin at a dose of 200 micrograms/kg by subcutaneous injection or no treatment and were then mixed with louse-infested animals for the winter housing period. All animals were examined for lice on treatment day and thereafter at weekly intervals for 13 weeks. In the preliminary study, acquisition of infestation in the face of a very mild challenge of Linognathus vituli was delayed by a mean period of 49 days in doramectin-treated animals compared with untreated controls. The difference in the delay between the groups was significant (P < or = 0.04). In the second study, test animals experienced a moderate challenge of a mixed infestation of L. vituli and Solenopotes capillatus. Acquisition of infestation was delayed by a mean period of 25.6 days in doramectin-treated animals compared with controls, the difference between the two groups being highly significant (P < or = 0.0001). These studies confirmed the protective efficacy of doramectin against sucking lice under natural challenge conditions showing that infestation is prevented for a period of about 4 weeks following administration of the drug at its recommended dose.

Compensating for dispersion and the nonlinear Kerr effect without phase conjugation

We propose the use of a dispersive medium with a negative nonlinear refractive-index coefficient as a way to compensate for the dispersion and the nonlinear effects resulting from pulse propagation in an optical fiber. The undoing of pulse interaction might allow for increased bit rates.

Bright temporal solitonlike pulses in self-defocusing AlGaAs waveguides near 800 nm

We report the experimental observation of bright temporal solitonlike pulses propagating in a material with a negative nonlinearity and positive (normal) dispersion. We believe this to be the first observation of bright solitonic pulses in a material with a negative Kerr nonlinearity. We have observed a gradual narrowing of the output pulse width as a function of increasing input power, and our results agree well with simulations.

Degenerate four-wave mixing geometry in thin-film waveguides for nonlinear material characterization

We demonstrate experimentally a new degenerate four-wave mixing (DFWM) geometry in waveguides that permits the simultaneous determination of the nonlinear refractive index, the absorption, and the response time of the thin-film materials. The geometry consists of two guided pumps in a planar waveguide with an unguided probe. We achieve nonlinear characterization by measuring only the DFWM signal and the guided pump power at the waveguide output. The technique has been tested on a polymeric film (di-alkylaminonitro- stilbene).

All-optical switching in two cascaded nonlinear directional couplers

We report on what is to our knowledge the first demonstration of all-optical switching in two integrated nonlinear directional couplers cascaded together in series. The directional couplers were fabricated from AlGaAs and operated at a wavelength of 1.53 microm, which corresponded to the half-band gap. The two devices were fabricated on the same chip, thereby eliminating coupling and reflection losses. We also report on the effects of pulse breakup.

Pathophysiology and treatment of negative symptoms

The assessment and clinical characterization of the negative symptoms of schizophrenia are reviewed. While negative symptoms may be secondary to positive symptoms, extrapyramidal side-effects, depressive illness, chronic institutionalization or other factors, they may also be primary, i.e., integral to the disease process itself. Recent literature has suggested that negative symptoms may represent a distinct pathophysiological process mediated in part by serotonergic mechanisms. Atypical neuroleptics, which have dual effects on D2/5-HT2 receptors, have demonstrated clinical efficacy on both negative and positive symptoms of schizophrenia, and might help to clarify the pathogenesis of these symptom clusters.

Determination of neutralizing epitopes in variable domains I and IV of the major outer-membrane protein from Chlamydia trachomatis serovar K

Chlamydia trachomatis is a leading cause of sexually transmitted diseases and a number of strategies have been developed to produce vaccines to prevent its transmission. The purpose of this study was to map the neutralizing epitopes of C. trachomatis major outer-membrane protein (MOMP) serovar K by using anti-MOMP antibodies and synthetic peptides. Seven anti-MOMP monoclonal antibodies and three polyclonal antisera were produced and characterized. Their fine specificity was defined by direct binding assay on 15 peptides of 10 amino acid residues, overlapping by five residues, corresponding to the four variable domains (VDI-VDIV: residues 64-85, 139-160, 224-237 and 287-319) of MOMP serovar K. Our data confirmed that a neutralizing epitope is found in VDIV, defined by peptides K12 and K13. This epitope is 296TTLNPTIAG304, which has never been reported as a neutralizing epitope of serovar K. Another neutralizing epitope, defined by peptide K2, has been identified in VDI. This epitope is in the same position as 71VAGLEK76, a peptide with neutralizing activity found in serovar A, but they are not identical because antibodies against peptide K2 do not bind to this epitope. No neutralizing epitope was found in the two other variable domains (VDII and III). In summary, two neutralizing sites, one in variable domain I and one in variable domain IV, were identified in serovar K.

Characterization of the humoral response induced by a synthetic peptide of the major outer membrane protein of Chlamydia trachomatis serovar B

The major outer membrane protein of Chlamydia trachomatis has been extensively studied and is still considered one of the most promising candidates for development of a synthetic vaccine. Neutralizing epitopes in variable domains I, II, and IV have already been reported. In variable domain I, residues 69 to 78 have been identified as a neutralizing epitope for some of the C- and C-related complex serovars (A, C, I, J, L3, and K). It is not known whether epitopes located at the same position in B-complex serovars are neutralizing. To clarify this point, rabbit polyclonal antibodies directed against the peptide 69TTTGNAVAPS78 from the B serovar were produced. Rabbit antisera were further rendered peptide specific by purification on a peptide-bovine serum albumin-Sepharose affinity column. Peptide-specific rabbit immunoglobulin reacted with five of the B-complex serovars (B, Ba, E, L1, and L2) by immunoblot and by direct-binding enzyme-linked immunosorbent assay. Furthermore, this peptide-specific rabbit immunoglobulin neutralized the chlamydial infectivity of both serovars B and E for HaK cells in a complement-independent in vitro assay. The importance of these results stems from the fact that peptide 69TTTGNAVAPS78 was able to induce an antibody response directed against B- and B-related complex serovars, including serovar E, which is responsible for a high proportion of genital infections. This peptide could therefore be considered for the construction of a multivalent synthetic vaccine.

Integrated ultrafast saturable absorber

An ultrafast saturable absorber was demonstrated experimentally in AlGaAs, operated with a photon energy below half the band gap, near 1555 nm. Both the saturation intensity and the linear transmission can be independently designed in the structure. The device is based on spatial soliton emission from a tapered channel waveguide with a corresponding increase in transmission of 50%. The experimental data compare favorably with numerically simulated results.

Mimicry of a neutralizing epitope of the major outer membrane protein of Chlamydia trachomatis by anti-idiotypic antibodies

The major outer membrane protein (MOMP) is a primary target antigen for the development of chlamydial vaccine. This protein is composed of four variable domains (I to IV) flanked by constant regions. Some of the variable domains contain antigenic determinants that elicit a neutralizing antibody response. Murine monoclonal antibodies (MAbs) against three nonoverlapping epitopes of MOMP were developed. One of these, called DP10, bound to all serovars, as shown by immunoblot analysis, and neutralized chlamydial infectivity for hamster kidney (HaK) cells in a complement-independent in vitro assay. Furthermore, analysis of the fine specificity of this MAb showed that it recognized a synthetic peptide contained within variable domain IV of the MOMP. Anti-idiotypic antibodies (aId) directed against this anti-MOMP MAb were produced in rabbits. These aId specifically bound to the relevant idiotype (DP10) and inhibited the binding of anti-MOMP MAb (DP10) to MOMP preparations in a dose-dependent fashion. The specificity of our aId for the binding site of anti-MOMP MAb is further suggested by the binding inhibition of affinity-purified aId to DP10 by the synthetic peptide defined by the idiotype. In addition, these aId also reacted with anti-MOMP antisera from rats and mice, suggesting an idiotypic cross-reactivity between these species. Finally, immunization of naive mice with aId induced an antibody response directed against the peptide defined by our anti-MOMP MAb and with neutralizing activity. Taken together, these data suggest that aId mimic a neutralization site on MOMP and could serve as a surrogate antigen to induce protective immunity against Chlamydia trachomatis.

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.

[Mediastinal parathyroid adenomas on a 5th ectopic gland. 2 case reports]

Mediastinal parathyroid adenoma located on the 5th ectopic gland is rare. We report here two new cases diagnosed by scintigraphy. In one case the adenoma was found to be located in the mediastinum prior to cervicotomy. The modern imaging methods capable of locating parathyroid adenomas are evaluated.

[Duration of antidepressive treatments]

In spite of the considerable amount of research undertaken in the field of biological psychiatry, there is currently no reliable guide allowing us to predict with accuracy the response of a patient to an antidepressant treatment. Moreover, owing to the heterogeneity of the spectrum of affective disorders, to the importance of eliminating the various factors involved in an apparent resistance to an antidepressant therapy, it seems aleatory, particularly for an individual patient, to foresee precisely the length of an antidepressant treatment, except may be in unipolar disorders. The quality of the physician-patient therapeutic relationship should never be neglected. The recent hypotheses pertaining to the etiopathogenesis of affective disorders, the advent of new psychotropic agents such as the specific serotonin uptake inhibitors, or other agents not acting through this mechanism and the MAOI, type A, as well as the utilization of corticosuppressor drugs, may pave the way to new therapeutic avenues that could, in the future, modify the prognosis and the duration of the treatment of the depressive affective disorders.

Effects of threephoton absorption on nonlinear directional coupling

The effects of three-photon absorption on nonlinear directional coupling in semiconductors below half the gap are studied for both cw and sech(2) pulse signals. The figure of merit associated with three-photon absorption includes not only material properties but also device design parameters. Numerical results show that at high powers, three-photon absorption significantly degrades nonlinear coupling, reduces throughput, and distorts output pulses. Good agreement is found between the theoretical model and experimental data.