Spatiotemporal resonances in a microfluidic system.

We report on the experimental observation of a spatiotemporal resonance phenomenon, in which a temporal excitation locks with a spatial pattern in an open flow system. The observation is made in a microfluidic system. We obtain the expected regimes--mixing and resonant patterns--in qualitative agreement with the theory. As an application, we realized a dual system particle extraction-micromixer.

[Hypothyroidism: clinical and etiological aspects in Cotonou (Republic of Benin)]. / Les hypothyroïdies: aspects cliniques et étiologiques à Cotonou (Bénign).

To evaluate the frequency of clinical manifestations and to study the etiological aspects of hypothyroidism in hypothyroid patients in Cotonou, we carried out a retrospective analysis of the medical reports on hypothyroid patients followed in our clinical practice. A total of 33 patients was thus studied, comprising 8 men (24%) and 25 women (76%) with mean age of 45,8 years for men and 40,4 years for women. The more frequent clinical manifestations observed were: face edema (45%), weight gain (45%), paresthesia (42%), fatigue (39%), lethargy (30%) and bradycardia (24%). Constipation (12%), sensation of cold (9%), depilation (6%) and dry skin (6%) were less frequently observed. Myalgia, hoarseness and menstrual irregularities were present in 15% of the cases respectively. Regarding the etiology, 82% of the cases were primary hypothyroidism and only 18% were of central origin. Thyroidectomy was the leading cause in our hypothyroid patients, representing 70% of all cases and 85% of primary hypothyroidism. Radioiodine treatment and autoimmune thyroiditis were equally found in 6% of the cases. Central hypothyroidism was related to a pituitary adenoma in four cases (12%) and to Sheehan syndrome in two cases (6%). As it can be expected, hypercholesterolemia was present in 82% of the patients but creatine phosphokinase elevation was more frequent (94% of the patients). Compared to the data reported in the literature, the frequency of the symptoms and signs of hypothyroidism seems to be underevaluated in our study and the frequency of autoimmune thyroiditis as a cause of hypothyroidism is low.

[A 4-year evaluation of ultrasonographic studies of liver pathology at the CNHU at Cotonou: apropos of 632 tests]. / Bilan de quatre années d'exploration échographique de la pathologie hépatique au CNHU de Cotonou: à propos de 632 examens.

This four year evaluation at the CNHU in Cotonou had the aim to assess the frequency and to define any particular aspects of liver disease as diagnosed by ultrasound examination. The study included 632 patients, aged from 15 to 87 years, who came from throughout Benin for examination by abdominal echography. Abdominal pains, abdominal masses and hepatalgia were the most common justifications for the examination. However, there was no clinical information for 8.08% of the patients. Homogeneous hepatomegalies were comprised of steatosis (3.78%), cardiac congestive liver (2.69%) and cirrhosis (2.53%) which could be diagnosed only in homogeneous forms. The heterogeneous cirrhosis forms were compounded with hepatocellular carcinoma (5.06%) in diffuse and micronodular forms. To improve the diagnosis of these two diseases it is necessary to develop the biopsy-puncture procedure as part of the pathological examination.

[Ultrasonography and amebic abscess of the liver at the CNHU at Cotonou: apropos of 33 cases]. / Echographie et abcès amibien du foie au CNHU de Cotonou: à propos de 33 cas.

From the 1st of March, 1991 to the 31st of December, 1995, 577 patients had abdominal echographic examinations which enabled the diagnosis of 33 cases of liver amebic abscesses. This study evaluated to what extent echography can facilitate the diagnosis and surveillance of patients during treatment in a region where immunological diagnosis of amebiasis is not yet performed and where percutaneous puncture is just beginning. Patients were suffering from chronic hepatic pain and fever in 28 cases. Seventeen patients had hepatomegaly and 14 patients had lost weight. Echographic images changed with time. In the beginning, there were diverse blurred structures which were 4 to 6 cm in diameter. Subsequently, the content of the abscesses became more homogeneous and in 3 cases the posterior area intensified. Also, the evolution of the disease during treatment by metronidazole could be followed by progressive echographic imaging. All the patients recovered without after-effects and only four of them showed hyperechogenic cicatrization. Two patients had an evacuation of their abscess which resulted in distinct improvement. The authors recommend generalization of that technique in all the hospitals across the country. Echography can thus improve both the diagnosis of liver amebic abscesses and the surveillance during the treatment.

Apport de l'ELISA et du Test Immunoblot deuxieme generation dans le diagnostic des hepatopathies virales C : a propos de 13 cas colliges au C.N.H.U. de Cotonou

Treize patients presentant une hepathopathie ont ete soumis au depistage des marqueurs seriques du virus de l'hepatite C (VHC) par la methode ELISA suivie de la confirmation par un test immunoblot de deuxieme generation. Cinq patients sur les treize etaient porteurs d'anticorps specifiques anti-VHC. Ce resultat preliminaire suggere que le VHC jouerait un role non negligeable dans le developpement des hepatopathies au Benin

Helicobacter pylori et pathologie gastrique au Benin

Une etude prospective conduite du 2/01/1994 au 31/08/1994 au Centre National Hospitalier et Universitaire et au Centre Medical Saint Luc de Cotonou a determine la prevalence de l'infection a Helicobacter pylori (HP) chez 202 patients atteints de differentes affections gastriques. Le diagnostic des lesions gastriques a ete histologique. HP a ete identifie dans la muqueuse gastrique par le test a l'uree et la culture. La combinaison des 2 methodes montre que l'infection a HP est associee a la gastrite chronique dans 66;5 pour cent; a l'ulcere gatrique dans 64;7 pour cent et a la dyspepsie non ulcereuse dans 9 pour cent des cas. La pathologie gastrique et duodenale en Afrique est largement dominee par les gastrites; les duodenites et ulceres. Dans l'ethiopathogenie de ces lesions; de nombreux facteurs sont incrimines dont le plus recent est Helicobacter pylori decouvert en 1983. Si en France et aux U.S.A; ce microorganisme a fait l'objet de nombreuses etudes; en Afrique; par contre; le caractere assez recent de cette decouverte; l'absence d'Unite d'Endoscopie Digestive et de laboratoires equipes pour les recherches sur HP dans bon nonmbre d'hopitaux africains expliquent le nombre reduit des travaux qui lui sont consacres. Les travaux liminaires de HOOUNGBE et KODJOH au Benin; DIOMANDE en Cote d'Ivoire; LACHLAM au Kenya; HOLCOMBE au Nigeria et ROUVROY au Rwanda donnent une idee de l'ampleur du probleme. Le present travail se propose de determiner la place de HP dans la survenue des affections gastriques en s'aidant au mieux des techniques modernes de diagnostic

[The contribution of endoscopy in the diagnosis of esophago-gastro-duodenal disorders in a tropical milieu. Experience in Benin with 930 examinations]. / Apport de l'endoscopie au diagnostic des affections oeso-gastro-duodénales en milieu tropical. Expérience béninoise à propos de 930 examens.

The authors analyse the results of esophago-gastro-duodenal fibroscopy in 930 symptomatic patients. Ninety one per cent of them had lesions. Inflammatory pathology was predominant: esophagitis, gastritis and duodenitis were seen in 21.5%, 47% and 29.08% respectively of the patients investigated. Gastritis accompanied 75.13% of cases of esophagitis and 76.4% of duodenitis, and was associated with the demonstration of the presence of Helicobater pylori in gastric biopsies in 56.41% of patients with that lesion. The relatively high incidence of carcinoma of the esophagus (2.7%) is a particular feature of this study, while that of carcinoma of the stomach (1%) was in accordance with classical data. Duodenal ulcer was found in 18% of patients as compared with 5.16% for gastric ulcer. From a pathophysiological standpoint, mention is made of traditional diet (hot, highly spiced), self-medication and intestinal parasite infestation in causing inflammatory lesions. Finally, emphasis is placed upon the role of Helicobacter infection in the development of chronic gastritis. The high rate of infection with this organism and its involvement in the mechanisms of duodenal ulcerogenesis could explain the high incidence of duodenal ulcers in our group and in studies emanating from developing countries.