Using Positive Spanning Sets to Achieve d-Stationarity with the Boosted DC Algorithm.

The Difference of Convex functions Algorithm (DCA) is widely used for minimizing the difference of two convex functions. A recently proposed accelerated version, termed BDCA for Boosted DC Algorithm, incorporates a line search step to achieve a larger decrease of the objective value at each iteration. Thanks to this step, BDCA usually converges much faster than DCA in practice. The solutions found by DCA are guaranteed to be critical points of the problem, but these may not be local minima. Although BDCA tends to improve the objective value of the solutions it finds, these are frequently just critical points as well. In this paper we combine BDCA with a simple Derivative-Free Optimization (DFO) algorithm to force the d-stationarity (lack of descent direction) at the point obtained. The potential of this approach is illustrated through some computational experiments on a Minimum-Sum-of-Squares clustering problem. Our numerical results demonstrate that the new method provides better solutions while still remains faster than DCA in the majority of test cases.

Gradient Methods on Strongly Convex Feasible Sets and Optimal Control of Affine Systems.

The paper presents new results about convergence of the gradient projection and the conditional gradient methods for abstract minimization problems on strongly convex sets. In particular, linear convergence is proved, although the objective functional does not need to be convex. Such problems arise, in particular, when a recently developed discretization technique is applied to optimal control problems which are affine with respect to the control. This discretization technique has the advantage to provide higher accuracy of discretization (compared with the known discretization schemes) and involves strongly convex constraints and possibly non-convex objective functional. The applicability of the abstract results is proved in the case of linear-quadratic affine optimal control problems. A numerical example is given, confirming the theoretical findings.

On the convergence of the gradient projection method for convex optimal control problems with bang-bang solutions.

We revisit the gradient projection method in the framework of nonlinear optimal control problems with bang-bang solutions. We obtain the strong convergence of the iterative sequence of controls and the corresponding trajectories. Moreover, we establish a convergence rate, depending on a constant appearing in the corresponding switching function and prove that this convergence rate estimate is sharp. Some numerical illustrations are reported confirming the theoretical results.

Venous bullet embolism to the right ventricle.

Bullet embolism is a rare complication of penetrating vascular trauma that requires a high index of suspicion for timely diagnosis and management. Delays in identification may result in poor early management and subsequent loss of limb or life [1]. There are two types of bullet embolism: arterial and venous. In this report, we discuss a rare case of venous bullet embolus to the right ventricle from the right femoral vein.

Fibromuscular dysplasia of the renal artery responsible for renovascular hypertension: a histological presentation based on a series of 102 patients.

BACKGROUND: Fibromuscular dysplasia (FMD) is a rare non-atherosclerotic and non-inflammatory disease in the arterial system. The purpose of the study was a retrospective analysis of FMD in the renal artery. PATIENTS AND METHODS: A total number of 102 patients (mean age: 36.9 years) who suffered from renovascular hypertension underwent a surgical therapy. The operative specimens of the renal arteries were analysed with the lightmicroscop using histological and immunohistochemical methods. RESULTS: 101 patients (99.02%) presented a medial FMD (extensive-medial subtype in 56 patients, 54.9%, subadventitial subtype in 29 patients, 28.4% and combined subtype in 16 patients, 15.7%). In 1 patient (0.98%) an adventitial FMD was found. We observed the following complications: true and dissecting aneurysms (75 patients, 74.5%), arterio-venous fistulae (2 patients, 1.96%) and chronic thrombosis (10 patients, 9.8%). CONCLUSIONS: With the progress in angioplasty, not all patients suffering from FMD undergo a primary surgical therapy and therefore this lesion is less seen in the daily work of the histopathologist.

Plasmodium chabaudi chabaudi chronic malaria and pathologies of the urogenital tract in male and female BALB/c mice.

BALB/c mice of both sexes were infected with a non-virulent strain of Plasmodium chabaudi chabaudi and any pathologies occurring in the urogenital tract and its accessory glands were investigated. Organs and tracts were removed from infected and control mice at 15, 40 and 100 days post-injection, weighed and processed for macroscopical and histological analyses. The relative weights of preputial, clitoral glands and testes were modified in infected mice during the 40 days following infection. The preputial glands show a marked hypotrophy at 15 days post-infection. The bladders of half of the infected female mice and a few infected male mice displayed a conspicuous haemoglobinuria and frequent interstitial cystitis that worsened throughout the experiment. Also, several chronic inflammatory reactions were detected in the prostates, preputial and clitoral glands up to 100 days post-infection. A probable cause of such a divergence in the characteristics of the infection and in the nature of the pathologies identified in infected male and female mice is the interaction between the infection and the immune and endocrine systems of the host. The cause of the pathologies and their consequences on the host condition are discussed.

Histological study of Trichosomoides nasalis (Nematoda: Trichinelloidea) in the nasal cavities of the murid Arvicanthis niloticus, with associated pathology.

Histological study of the nasal cavities and upper maxillae of Arvicanthis niloticus naturally infected with Trichosomoides nasalis shows that the female worms reside in the epithelial monolayer of the nasal mucosa of the posterior and median cavities. Eggs laid by T. nasalis were infiltrated between the female body wall and the epithelial lining. Small groups of eggs, mixed with mucus and polymorphonuclear cells, were found in the nasal lumen, freed by rupture of the stretched epithelium. Two females and a few eggs were also found in the connective tissues. One male was found in a female uterus and two were apparently in the lumen of the nasal cavity but the surrounding tissues were disrupted. No male was identified in the lamina propria of the mucosa. However, significant inflammatory lesions occurred in the lamina propria, similar to those induced by the males of Anatrichosoma spp. which live in this part of the mucosa. In rodents, the lesions resulted in rhinosinusitis characterised by a lymphocytic infiltration leading to nasal obstruction.

Intestinal migrations of Trichostrongylus retortaeformis (Trichostrongylina, Trichostrongylidae) in the rabbit.

Observations were made on histological sections of the stomach and small intestine of seven rabbits infected with Trichostrongylus retortaeformis and from one uninfected control rabbit. At 12h post-infection, larvae were found in the small intestine. At first, only a few larvae were observed entering the mucosa through capillaries of the stroma of villi; the majority of larvae remained in the intestinal lumen, within mucus of the crypts. We consider that the presence of the worms in the stroma is the result of a larval migration. From a phyletic point of view, this migration is interpreted as an ancestral memory of the pulmonary migration seen in the primitive Strongylida.

[Necrotic eosinophilic angiitis with ileal perforation and peritonitis secondary to abdominal angiostrongyliasis]. / Angéite nécrosante à éosinophiles avec perforation iléale et péritonite secondaire à une angiostrongylose abdominale.

INTRODUCTION: Abdominal angiostrongyliasis caused by the filiform nematode Angiostrongylus costaricensis, is an endemic disease in Central and South America. A case of necrotic eosinophilic angeitis with ileum perforation and peritonitis due to abdominal angiostrongyliasis is reported. OBSERVATION: A 32 year-old man, living in a Paris suburb, underwent segmentary resection of the ileum with end to end anastomosis for perforation with generalized peritonitis. The anatomopathological examination revealed eosinophilic necrotic lesions with thrombosis on the borders of the ileum perforation. The discovery of a section of A. costaricensis in the lumen of a nearby muscular artery initiated an epidemiological survey, revealing that the patient had visited French Guyana 2 months earlier. DISCUSSION: Angiostrongylus costaricensis is a nematode parisiting certain forest rodents that become its permanent host. The intermediate hosts are earth molluscs or slugs of the same family. Humans are accidentally infected following ingestion of vegetables infested with L3 larvae or slugs carrying the disease. The clinical symptomatology is unspecific: prolonged fever, anorexia, and right iliac fossa pain with eosinophilia of the blood. Often benign, the progression of abdominal angiostrongylosis is punctuated by complications: occlusive syndrome, generalised peritonitis due to intestinal perforation and mass syndrome. Hemorrhage, infarct, pseudo-tumoural fibrosis and ulcers represent the surgical or macroscopic rearrangements. In the tissue, 4 lesions characterize abdominal angiostrongylosis: eosinophilic necrotic angeitis, foreign body granulomas, eosinophilia in the digestive wall, and the presence of A. costaricensis in the lumen of the vessels. There is presently no medical treatment and surgery is the only therapeutic option.

Primary squamous cell carcinoma of the endometrium: case history, pathologic findings, and discussion.

Primary squamous cell carcinoma of the endometrium (PSCCE) is an exceedingly rare tumor. Rarely are cytological criteria discussed. We report our experience in the cytological diagnosis of a case. A postmenopausal, 64-yr-old woman suffered from pyometria. An endometrial Pap smear displayed some malignant squamous cells. Curettage of the cervix and the uterine cavity only recovered some fragments of atypical squamous epithelium whose origin could not be precisely identified. A hysterectomy with bilateral adnexectomy was decided upon. Pathological study evidenced a primary squamous cell carcinoma in the uterine cavity while the cervix was tumor-free and the lymph nodes were devoid of metastases (pT1, pN0, pM0). The patient died 46 mo PO with multiple pulmonary and renal metastases. The histological feature of PSCCE is identical to that of any tumor of a similar nature, whatever the site, especially the cervix. Confirmation of the primary endometrial nature is only possible on the hysterectomy specimen.

[Visceral lesions in mammals and birds exposed to agents of human cercarial dermatitis]. / Lésions viscérales de mammifères et oiseaux, exposés aux agents de dermatite cercarienne humaine.

Over the past few years, the cercarial dermatitis has become a new problem of public health, obviously linked to the prolonged stay of migrant birds on our territory. This is a skin affection characterized by pruriginous and papulous eruptions caused by penetration of avian bilharzian larvae under the skin. These larvae are emitted by molluscs, mostly limneids. In aquatic birds, especially in migrating Anatidae, these larvae reach the visceral vessels, become adults in a few weeks, lay eggs, then degenerate. Corresponding miracidia contaminate new limneids. Since 1993, the total number of annual cases of cercarial dermatitis has increased from only ten to thousands in France and the affection rages in pools where limneids, migrating water birds and swimmers gather together. Fever, respiratory and/or digestive allergic symptoms appear in some cases. This clinical pattern has encouraged to undertake research on the future of these bilharzian larvae in mammals organism. A preliminary investigation on a rodent model showed that, once the skin barrier had been crossed, the schistosomulae migrated into the lungs of the host; there they survived a week and induced lesions. The goal of this study is to carry on the research, over a longer period, after exposure to cercariae, simultaneously in mammals and birds, with two species of bilharziae present in France. The selected models are the gerbil Meriones unguiculatus for mammals, and the ducks Anas platyrhynchos and Cairina moschata, for birds. 5 M. unguiculatus and 2 A. platyrhynchos were exposed to cercariae emitted by Radix auricularia; 2 gerbils and 5 A. platyryhnchos to larvae of R. peregra, 3 C. moschata to larvae emitted by two species of molluscs: 70-230 from R. auricularia and 330-585 from R. peregra. 5 gerbils died between 2 and 5 weeks after exposure, 2 gerbils sacrificed early, served as control animals for skin manifestations. Eight ducks were sacrificed between 2 and 4 weeks after; the 2 last ones, exposed several times, were sacrificed respectively 7 and 13 weeks after the first exposure. Visceral and skin samples were submitted to histological study. The control gerbils developed skin dermatitis. In ducks, R. auricularia was the vector of Trichobilharzia franki, whose selective dwelling site was the mesentery; R. peregra was the vector of an indeterminate species found in the lungs and nose. This species is called Bilharzia sp. in this study. The ducks, exposed to two kinds of larvae, displayed worms in these two main locations. In gerbils, T. franki induced lesions in the mesenteric veins and the peritoneum. Bilharzia sp. gave rise to lesions in lung arteries, pleura and liver veins. Vascular changes encompassed endothelitis and lymphocytic vasculitis, while serosa displayed mesothelial hyperplasia. The types of lesions observed in gerbils were noticed in ducks, and, according to the species of bilharzia, in the homologous viscera. Additional foreign body granulomas centred on worm's debris or their eggs, and vascular thromboses were present, too. In addition, ducks displayed lesions involving several other viscera including the intestine, the kidneys and the peripheral nerves. These changes were multiple and diffuse in C. moschata exposed to two species of bilharziae. They were observed mainly in mesenteric and intestinal vessels, pulmonary arteries and hepatic veins. In gerbils, the lesions persisted 2 to 5 weeks after exposure, but worms were not identified in the neighbouring tissues near the damaged vessels. In ducks, lesions were important between 2 and 7 weeks after exposure; they co-existed with live or dead worms, sometimes paired, with or without eggs. The hepatic lesions regressed 13 weeks, after exposure. In mammals and birds, young worms could migrate into the same visceral vessels, and stimulating formation of persistent lesions. In individuals exposed to the same cercariae, development of similar lesions would be probable.

[Remodelling the aortic root by resection of the ascending aorta and non-coronary sinus in annular dilatation of the aorta and acute dissection of the descending aorta. 29 observations]. / Remodelage du culot aortique par résection de l'aorte ascendante et du sinus non coronaire dans la maladie annulo-ectasiante aortique et la dissection aiguë de l'aorte ascendante. 29 observations.

The first conservative surgical procedures of the native aortic valve in annular dilatation were performed by Yacoub and David [1, 2]. These so-called remodelling and inclusion procedures provided hope for a normal life without long-term anticoagulant therapy for patients with Marfan's syndrome, with protection from the complication of an acute dissection of the ascending aorta. The authors reported their experience in the Archives des Maladies du Coeur et des Vaisseaux in 1999, with excellent results [3]. However, a certain number of cases are encountered in which the Yacoub and David procedures cannot be performed because of the presence of a pseudo-bicuspid valve, isolated asymmetrical dilatation of the non-coronary sinus or acute dissection of the aorta without dilatation of the aortic root. In these forms, the authors have developed a technique of remodelling the aortic root with conservation of the native valve by resecting the ascending aorta and non-coronary sinus, rather than carrying out a Bentall procedure. Twenty-nine cases of this type have been treated in this way for three different indications: aneurysm of the ascending aorta with bicuspid aortic valve, aneurysm of the ascending aorta with aortic insufficiency and extension to the posterior sinus, and type A acute dissection of the aorta.

The migration and localization of Loa loa infective and fourth-stage larvae in normal and immunosuppressed rodents.

The migration and localization of the human filarial parasite Loa loa in laboratory mice (BALB/c and Swiss) and jirds (Meriones unguiculatus) was investigated. The rodents, either left immunocompetent or immunosuppressed with hydrocortisone, were each inoculated subcutaneously or intraperitoneally with 50 or 200 infective, third-stage larvae (L(3)) of L. loa. Groups of the rodents were killed at various times post-infection, up to day 40, to enable histological studies and permit developing larvae to be recovered. Larvae survived and developed for only 1 week in the immunocompetent rodents but for a mean of 3 weeks in the immunosuppressed. Most of the larvae were found in the subcutaneous tissues (81.9%), peritoneal cavity (14.9%), pleural cavity (1.8%) or the lungs and heart (1.3%) and none was detected in the spleen, kidney, intestine, liver or pancreas. Localization of the larvae appeared unaffected by the site of inoculation, the rodent species or strain, or the dose of L(3) used. The recovery of larvae (as a percentage of the number inoculated) was better among the rodents inoculated with 50 L(3) each than among those given four times as many L(3). The results of the histological studies not only confirmed the presence of larvae in the subcutaneous tissue (72.5%), muscles (11.7%) and peritoneal and pleural cavities (7.8%) of the infected rodents but also revealed worms in the lymphatic vessels of the mesentery and spinal cord (7.3%). These results indicate that most L. loa L(3) inoculated into a mammalian host localize in the cutaneous sites and that only a small proportion of them might migrate, using the lymphatic system, into the internal organs. The observation of migrating L. loa larvae in the lymphatic vessel of the meningeal envelope of the spinal cord, albeit in an experimental host, may explain why, in areas where human loiasis is endemic, neurological manifestations occasionally occur in those with L. loa infections.

B-cell deficiency suppresses vaccine-induced protection against murine filariasis but does not increase the recovery rate for primary infection.

To establish the role of B cells and antibodies in destroying filariae, mice lacking mature B cells and therefore unable to produce antibodies were used. Litomosoides sigmodontis offers a good opportunity for this study because it is the only filarial species that completes its life cycle in mice. Its development was compared in B-cell-deficient mice (BALB/c muMT mice) and wild-type BALB/c mice in two different in vivo situations, vaccination with irradiated larvae and primary infection. In all cases, mice were challenged with subcutaneous inoculation of 40 infective larvae. Vaccine-induced protection was suppressed in B-cell-deficient mice. In these mice, eosinophils infiltrated the subcutaneous tissue normally during immunization; however, their morphological state did not change following challenge inoculation, whereas in wild-type mice the percentage of degranulated eosinophils was markedly increased. From this, it may be deduced that the eosinophil-antibody-B-cell complex is the effector mechanism of protection in vaccinated mice and that its action is fast and takes place in the subcutaneous tissue. In primary infection, the filarial survival and growth was not modified by the absence of B cells. However, no female worm had uterine microfilariae, nor did any mice develop a patent infection. In these mice, concentrations of type 1 (gamma interferon) and type 2 (interleukin-4 [IL-4], IL-5 and IL-10) cytokines in serum were lower and pleural neutrophils were more numerous. The effects of the muMT mutation therefore differ from those in B1-cell-deficient mice described on the same BALB/c background, which reveal a higher filarial recovery rate and microfilaremia. This outlines B2-cell-dependent mechanisms as favorable to the late maturation of L. sigmodontis.

Variable extension of the transitional zone in the medial structure of carotid artery tripod.

BACKGROUND: The goal of our study was to demonstrate the extension of the transitional zone (TZ) between elastic and muscular medial structure in carotid artery tripod. PATIENTS AND METHODS: A histologic study of 56 probes from 8 carotid artery tripods was performed. The probes were obtained from autopsies of 4 adults (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 different topographic sites. RESULTS: At each level of the CCA (at 1 cm and 2 cm proximal to the bifurcation as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view field (200 x magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arterial type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) muscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sections (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions have prevented the assessment of the arterial type in 4 probes (7.1%). The TZ in the medial structure of carotid artery tripods is exclusively localized in the ICA/ECA but not in the CCA. The ICA/ECA presented a TZ with a length up to 0.5 cm (4 probes; 25%), up to 1.5 cm (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%). CONCLUSIONS: In this study we confirmed that in the carotid artery tripod, a TZ--an arterial segment with transition from elastic to muscular type--does exist, involving a variable length. Furthermore studies on the impact of the biomechanical properties of the TZ as a potential factor in atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ should be considered prior to interventional procedures.

Arterial calcifications: morphological aspects and their pathological implications.

Morphological aspects of calcifications are identical whatever their site in the arterial layers: fine granular deposits, plates, rings. Occurrence of complications: fibrosis with foreign body type granuloma, thrombosis, and embolism mainly depend on the site and the amount of calcification. Clinicians should be aware of these complications when performing angioplasty.

Fatal myocardial infarction in a young man caused by a right megadolicho-coronary artery with thrombosis: a case report.

A case of fatal myocardial infarction in a young man, secondary to thrombosis of an isolated ectatic coronary artery, is reported. Histological study of this abnormal artery demonstrated that it was of elastic type in its proximal two centimeters. This abnormal arterial structure supports the hypothesis of a congenital defect.