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F Roy

Publications and source records attributed to F Roy.

At least 19 recordsLinked to original sources
PubMed2006

VimA is part of the maturation pathway for the major gingipains of Porphyromonas gingivalis W83.

The authors have shown previously that the vimA gene, which is part of the bcp-recA-vimA operon, plays an important role in protease activation in Porphyromonas gingivalis. The gingipain RgpB proenzyme is secreted in the vimA-defective mutant P. gingivalis FLL92. An important question that is raised is whether the vimA gene product could directly interact with the proteases for their activation or regulate a pathway responsible for protease activation. To further study the mechanism(s) of VimA-dependent protease activation, the vimA gene product was further characterized. A 39 kDa protein consistent with the size of the predicted VimA protein was purified. In protein-protein interaction studies, the VimA protein was shown to interact with gingipains RgpA, RgpB and Kgp. Immune sera from mice immunized with P. gingivalis immunoreacted with the purified VimA protein. Taken together, these data suggest an interaction of VimA with the gingipains and further confirm the role of this protein in their regulation or maturation.

Adhesins, Bacterial↗
PubMed2006

HtrA in Porphyromonas gingivalis can regulate growth and gingipain activity under stressful environmental conditions.

In several micro-organisms, HtrA, a serine periplasmic protease, is considered an important virulence factor that plays a regulatory role in oxidative and temperature stress. The authors have previously shown that the vimA gene product is an important virulence regulator in Porphyromonas gingivalis. Further, purified recombinant VimA physically interacted with the major gingipains and the HtrA from P. gingivalis. To further evaluate a role for HtrA in the pathogenicity of this organism, a 1.5 kb fragment containing the htrA gene was PCR-amplified from the chromosomal DNA of P. gingivalis W83. This gene was insertionally inactivated using the ermF-ermAM antibiotic-resistance cassette and used to create an htrA-deficient mutant by allelic exchange. In one randomly chosen isogenic mutant designated P. gingivalis FLL203, there was increased sensitivity to hydrogen peroxide. Growth of this mutant at an elevated temperature was more inhibited compared to the wild-type. Further, in contrast to the wild-type, there was a significant decrease in Arg-gingipain activity after heat shock in FLL203. However, the gingipain activity in the mutant returned to normal levels after a further 30 min incubation at room temperature. Collectively, these data suggest that HtrA may play a similar role in oxidative and temperature stress in P. gingivalis as observed in other organisms.

Adhesins, Bacterial↗
PubMed2004

Aneurysm of the pancreaticoduodenal arteries with a celiac trunk lesion: current management.

OBJECTIVE: We report a ruptured aneurysm of the pancreaticoduodenal arteries without acute or chronic pancreatitis but associated with a median arcuate ligament division that compressed the celiac trunk, an exceptional event, thus far described in only 11 patients. We also conducted a targeted review to seek information about clinical presentation, to hasten diagnosis and assist in therapeutic management. METHODS: A 54-year-old man with retroperitoneal hemorrhage associated with an arcuate ligament division, documented on computed tomographic scans, underwent diagnostic arteriography and embolization to treat the bleeding aneurysm. In a second elective operation the causative arcuate ligament was sectioned to decompress the celiac artery, to prevent aneurysm recurrence. RESULTS: Embolization stopped the aneurysmal bleeding, and arteriograms showed that surgical sectioning resolved the celiac trunk stenosis. At 1-year follow-up the patient had no signs of complications or recurrence of disease. CONCLUSION: Ruptured aneurysm of the pancreaticoduodenal arteries associated with stenosis of the celiac trunk is a surgical emergency. Although a literature review disclosed no significant difference between outcomes after open surgery and radiologic arterial embolization, our experience in this case suggests immediate embolization during arteriography as the most effective treatment. Later, to prevent recurrence, the arcuate ligament should be surgically sectioned and the celiac artery stenosis treated.

Aneurysm, Ruptured↗
PubMed2003

[Immune response to equine Chorionic Gonadotropin used for the induction of ovulation in goats and ewes].

In dairy goats and ewes the use of equine Chorionic Gonadotropin (eCG) as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination (AI). Treatment for induction and synchronization of ovulation consists of a progestagen delivered by vaginal sponge, followed by an eCG injection. In some females, the first injection of eCG induces a humoral response with high concentrations of anti-eCG antibodies in contrast to other females displaying a very low concentration of anti-eCG antibodies. Females eliciting a low response were also poor responders after the following treatments. Conversely, high responders at the first treatment systematically yielded high immune responses upon the following treatment. By a molecular genetic approach using microsatellites we showed that the anti-eCG immune response phenotypes were associated with MHC class II polymorphism. Females with high residual antibody concentrations at the time of eCG injection exhibited a much lower kidding rate than other females did. Lower fertility of these females, inseminated at a fixed time after eCG treatment (43H for goats and 55H for ewes), might be due to the delay in estrus occurrence and the pre ovulatory LH surge. Consequently, under field conditions old females selected for AI are only those with low residual anti-eCG antibody concentrations and old females with high residual antibody concentration are culled from AI breeding because of their low fertility during the previous year. So we have undertaken comparative studies to establish if the anti-eCG immune response is correlated with the global immunity in animals.

Animals↗
PubMed2000

[Ultrasonographic diagnosis and prenatal management of fetal ovarian cysts].

OBJECTIVE OF THE STUDY: To evaluate the outcome of fetal ovarian cysts in relation to their ultrasonic appearance and size. To define, on that basis, the contribution of intrauterine aspiration. MATERIAL AND METHODS: Retrospective study of all ovarian fetal cysts detected by prenatal ultrasound examination (n = 25) during a 4 year period. All these cysts were followed during pregnancy and after delivery until spontaneous or surgical resolution. RESULTS: At the time of prenatal sonographic detection at the mean gestational age of 32 1/2 weeks, the mean cyst diameter was 43+/-17 mm and 36% of all these cysts were already complicated (fluid-debris level, septa or finding of a retracting clot). Among the 16 non-complicated cysts (echolucent and thin-walled) 44% became twisted during the perinatal period irrespective of the size or the time of discovery. At birth, all these complicated cysts underwent surgical treatment and needed oophorectomy or adnexectomy. Surgery was therefore performed in a total of 56% of neonates. The pathologic reports confirm in all cases the benign follicular or follicular lutein nature of the cysts. CONCLUSION: Due to this high rate of mechanical complications, cyst decompression may be considered at the time of diagnosis in case of an anechoic fetal ovarian cyst. The safety and efficacy of this approach, on the cases reported in the literature seem encouraging. Although, a prospective randomized evaluation is needed.

Female↗
PubMed2000

[An unusual thoracic opacity].

We report a case of a paraspinal meningocele in a 37-year-old man with no other clinical manifestation. The diagnosis was established on the basis of the computed tomography and magnetic resonance imaging features.

Adult↗
PubMed1999

The negative effect of repeated equine chorionic gonadotropin treatment on subsequent fertility in Alpine goats is due to a humoral immune response involving the major histocompatibility complex.

In dairy goats, the use of eCG as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination. However, repeated eCG treatments are followed by decreased fertility in goats inseminated at a fixed time after treatment. In this report, we show the presence of anti-eCG antibodies in plasma of treated goats. A 500 IU eCG injection induces a humoral response, with variable concentrations of anti-eCG antibody being produced in individual goats. The analysis of successive anti-eCG immune responses over several years has demonstrated the existence of different populations of goats, defined as low, medium, and high responders. By the use of two caprine microsatellites located inside (OLADRB) and outside (BM1258) the major histocompatibility complex (MHC), a significant association (p < 0.05) between the anti-eCG antibody response and some MHC-DRB alleles was found. Goats with high antibody concentrations at the time of eCG injection (> 2.5 microg/ml) exhibited a much lower kidding rate than did other females (41.3% vs. 66.7%). Lower fertility of these goats, inseminated at a fixed time after eCG treatment, might be due to the observed delay in estrus occurrence and the preovulatory LH surge.

Animals↗
PubMed1999

Humoral immune response to equine chorionic gonadotropin in ewes: association with major histocompatibility complex and interference with subsequent fertility.

In dairy ewes, the use of eCG as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination (AI). In this report we show the presence of anti-eCG antibodies in plasma of treated ewes. The major histocompatibility complex (MHC) was involved in the individual variability of the humoral immune responses to eCG. We found significant associations between the anti-eCG response phenotype and some MHC class II alleles. The low immune response phenotype was associated with one MHC class II allele only in Lacaune ewes, and the high immune response phenotype was associated with one MHC class II allele both in Manech and in Lacaune ewes. In herds, the impact of residual anti-eCG antibodies on subsequent fertility after AI seems minimal because of an indirect elimination of high-responder ewes from AI breeding. Therefore, the true magnitude of the association between residual anti-eCG antibody concentration and fertility has been underestimated. An additional experiment without any high-responder female elimination showed a significant correlation between high residual antibody concentrations and lower lambing rate after AI at a fixed time, possibly because of a delayed preovulatory LH surge. The results suggest that anti-eCG antibody concentration is one risk factor for infertility after AI.

Aging↗
PubMed1999

[Idiopathic granulomatous mastitis. Review of the literature illustrated by 4 cases].

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) was described as a specific entity in 1972 by Kessler and Wolloch. Despite the 120 cases reported in the international literature, this pathology remains quite unknown. MATERIAL AND METHODS: Four cases of idiopathic granulomatous mastitis are reported in this article in order to outline the main clinical features of this affection. Data in the literature were used to discuss diagnostic and therapeutic particularities. DISCUSSION: The histologic findings of a non-caseating granulomatous inflammation, centered on breast lobules, composed of epithelioid cells and multinucleated giant cells, allow establishing the diagnosis of granulomatous mastitis (GM). The main presenting symptom of GM is a single inflammatory mass of the breast; the diagnosis is thus often mistaken for breast carcinoma (more than 50% of the reported cases). Radiologic and cytologic findings alone do not enable reaching certain diagnosis because they cannot resolve the differential diagnosis of inflammatory process and malignancy. The diagnosis of IGM can be established after the etiological work up remains negative. A course of oral corticosteroid therapy, non-steroidian anti-inflammatory drugs, or colchicine can be used in order to shrink the breast mass, allowing more conservative surgery. Local excision is of limited benefit as there is a strong tendency for recurrence. CONCLUSION: Different therapeutic options of IGM are explained by its clinical variability. A more pragmatic therapeutic approach would be enabled by a new classification based on course and severity.

Adrenal Cortex Hormones↗
PubMed1999

Implications of recent advances in reproductive physiology for reproductive management of goats.

The control of reproduction in goats is interesting for technical reasons (synchronization of kiddings, adjustment to forage availability or to economy), and for genetic reasons (identification and dissemination of improved genotypes). The use of short-light rhythms leads to markedly increased production of semen per buck and prevents occurrence of a 'resting' season. Recent identification of a bulbourethral lipase in goat spermatozoa opens new perspectives in sperm preservation. Light plus 'short day' treatments also allow induction of out-of-season oestrous cycles and ovulations leading to enhanced fertility. Repeated use of eCG provokes the production of antibodies, delays the timing of ovulation and causes a reduction in fertility after fixed-time artificial insemination. All steps of embryo production, freezing and transfer are now controlled and allow the attainment of satisfactory numbers of kids born per donor female, which are compatible with the development of the technique for exchanging genotypes between countries. In vitro production of embryos allows high development rates to be achieved after in vitro maturation and fertilization of oocytes, and will ensure the production of synchronous populations of one-cell zygotes at the stage required by new biotechnologies.

Animal Husbandry↗
PubMed1998

International collaborative calibration of a preparation of equine chorionic gonadotrophin (eCG NZY-01) proposed as a new standard.

A batch of partially purified equine chorionic gonadotrophin (eCG NZY-01) was freeze-dried in vials of 500 iu and characterized in a large number of in vivo and in vitro assays. These assays were performed in eight laboratories in seven countries (Argentina, Belgium, England, France, Germany, Holland and USA). Four of these laboratories were in universities or government research organizations and four were those of pharmaceutical companies. Good correlation between in vivo and in vitro assays was found for unknown samples and for commercial preparations from different sources when performed against eCG NZY-01 as the standard. This result suggests that, in contrast to the WHO IRP2 international standard, the eCG NZY-01 preparation contains all eCG isoforms in proportions roughly similar to those found in serum and commercial preparations. The consistency of the data when using eCG NZY-01 as the reference in all types of in vivo and in vitro assays validates the wide use of in vitro assays which are cheaper, quicker and ethically preferable to in vivo assays. Vials of 500 iu eCG NZY-01 are available to researchers and manufacturers.

Animals↗
PubMed1996

Immobilized metal ion affinity capillary electrophoresis of proteins--a model for affinity capillary electrophoresis using soluble polymer-supported ligands.

An affinity capillary electrophoresis method has been developed that employs small ligands covalently bound to a replaceable soluble polymer matrix. The metal chelate iminodiacetate-Cu(II) coupled to polyethylene glycol was used as a model system and the interactions of different model proteins, namely ribonucleases, cytochromes c, chymotrypsin, and kallikrein, were investigated. The method allowed for easy determination of dissociation constants using a modified Langmuir adsorption isotherm equation which is applicable to interactions with fast on/off kinetics. It is shown that the general rules for protein interaction with matrix-bound metal chelates established for immobilized metal ion affinity chromatography (IMAC) are maintained in immobilized metal ion affinity capillary electrophoresis (IMACE). In contrast to gel electrophoresis, IMACE allowed for using similar conditions as in IMAC, especially regarding the high salt concentrations, usually employed with the latter technique. The usefulness of the method for quantification of low-affinity interactions and studying protein surface structure and structure/function relationship using the metal affinity is demonstrated.

Animals↗
PubMed1993

Extracellular matrix analogs as carriers for growth factors: in vitro fibroblast behavior.

Repair of connective tissue involves interactions between growth factors (GFs) and extracellular matrix (ECM) molecules. On the other hand, biological biomaterials could be used to carry and deliver GFs to stimulate wound healing. In the present study, fibroblasts were cultivated in a serum-free culture medium onto collagen (type I), hyaluronic acid, chondroitin sulfate, fibronectin, or fibrin. FGF, EGF, or PDGF was incorporated within those substrates. Using immuno- and radiolabeling assays, the distribution of GFs within the ECM analogs was relatively uniform and GFs retained in substrates were dependent on the substrates. Fibroblast replication was determined by the incorporation of [3H]-thymidine and compared to control groups. On collagen or chondroitin sulfate, the incorporation of GFs did not significantly improve cell proliferation. On hyaluronic acid, the incorporation of FGF and PDGF enhanced cell replication at 48 h. The incorporation of PDGF in fibronectin enhanced cell replication. On fibrin, the incorporation of PDGF, EGF, and FGF significantly enhanced cell replication. However, cell replication on FGF-incorporated fibrin was higher by 48 h than that on fibrin in the presence of FGF-supplemented culture medium. Fibrin sustains the biological activity of GFs, FGF in particular, and can be a carrier for GF that stimulates cell replication.

Biocompatible Materials↗
PubMed1990

Cardiovascular properties of LF 2.0254, a new potent vasoselective calcium channel blocker with a slow onset of action.

The effects of LF 2.0254, a new 1,4-dihydropyridine derivative, were studied in rabbit aorta stimulated by various contractile agents and in isolated guinea pig atria. LF 2.0254 inhibited in a time-dependent fashion K(+)- and CA2(+)-induced contractions of rabbit aorta with respective IC50 of 2.7 nM and 1.7 nM. An action of LF 2.0254 at the voltage operated calcium channel was consistent with the finding that LF 2.0254 antagonized 45Ca2(+)-uptake induced by depolarisation of smooth muscle, and since contractile responses evoked by (-) norepinephrine and the calcium ionophore A23187 were insensitive to the drug. In isolated paced left atria and spontaneously beating right atria of guinea pig, LF 2.0254 added for 60 min at 1 microM only slightly decreased the contractile force and beating rate. In anesthetized open-thorax dogs, LF 2.0254 (1 to 100 micrograms/kg, iv) dose-dependently lowered systemic blood pressure and increased cardiac output with a slower onset of action than nifedipine. LF 2.0254 and nifedipine decreased total peripheral, coronary, femoral and vertebral resistance. In marked contrast to nifedipine, LF 2.0254 induced only a slight decrease in left ventricular dP/dt. In conscious hypertensive dogs LF 2.0254 (0.1 and 0.3 mg/kg per os) decreased blood pressure and concomitantly increased heart rate and plasma renin activity. It is concluded that LF 2.0254 differ markedly from nifedipine in its more gradual onset of action and greater selectivity for the vasculature with respect to the myocardium.

Anesthesia↗
PubMed1988

Clinical efficacy of levamisole in the treatment of primary nephrosis in children.

The purpose of the study was to evaluate the efficacy and the toxicity of levamisole given for 1 year to 16 children suffering from minimal change primary nephrosis who were relapsing frequently. The overall results showed that under levamisole the relapse rate decreased by 55% and the steroid requirements by 50%. After cessation of levamisole administration, most children (11/16) relapsed again. A second course of levamisole treatment reduced the relapse rate significantly once again. At the dosage of 2.5 mg/kg given every other day for 1 year or more, no side effects of levamisole does not cure nephrosis but reduces the incidence of relapses for the period it is administered. It also reduces the steroid requirements without any important side effects.

Adolescent↗
PubMed1987

Comparative antihypertensive effects of nifedipine and nicardipine in adult and aged spontaneously hypertensive rats.

Effects of two dihydropyridine derivatives, nifedipine and nicardipine, on systolic blood pressure and heart rate in adult (4- to 5-month-old) spontaneously hypertensive rats (SHR) were studied in comparison with those in aged (11- to 12-month-old) SHR. Both calcium channel blockers induced similar dose-dependent hypotensive effects in 4- to 5-month- and 11- to 12-month-old SHR. The maximal hypotensive action of both calcium channel blockers was delayed in aged SHR compared to adult SHR. Nicardipine induced a similar reflex tachycardia in adult and aged SHR. In contrast to nicardipine there was no increase in heart rate after administration of nifedipine in aged SHR at same hypotensive effects. It is concluded that nifedipine and nicardipine are potent antihypertensive agents in aged SHR which differently affect heart rate.

Aging↗
PubMed1986

The effect of Bay K 8644 on angiotensin II-induced contractions of rabbit aortic strips.

The effect of Bay K 8644 on contractile responses to angiotensin II (AII) was investigated in rabbit aorta. Bay K 8644 alone did not elicit contraction while contractile responses to AII were enhanced at low concentrations (10(-8), 3 X 10(-8), 10(-7) M) and depressed at a higher concentration (10(-6) M). The potentiating effect was always observed and increased after treatment by phentolamine. These findings suggest that Bay K 8644 activates calcium channels operated by angiotensin receptors.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗