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Biomedical subjects

M Farah

Publications and source records attributed to M Farah.

At least 19 recordsLinked to original sources
PubMed2002

Rheological characterization of Poloxamer 407 lidocaine hydrochloride gels.

Thermal gelation of Poloxamer 407 lidocaine hydrochloride gels was characterized by rheological studies. Lidocaine, a local anesthetic used for treatment of acute and chronic pain, presents short duration action; thus a long-action single-dose injection would be of clinical importance. Poloxamer 407 gel can extend the release and the action of lidocaine. In the present work, aqueous gels with lidocaine containing different concentrations of Poloxamer 407 and additives like inorganic salts (NaCl, NaH(2)PO(4), Na(2)CO(3)) and PEG 400 were obtained. Viscosity measurements and the optimal sol-gel transition temperature were obtained by these rheological studies. Poloxamer 407 gels are viscoelastic materials because they have elastic modulus (G'), characteristic of solid materials, and viscous modulus (G"), characteristic of liquid materials. Poloxamer 407 gels are pseudoplastic; therefore, when shear deformed, their viscosity decreases. Increase of the polymer concentration increases the viscosity of the gels, which can change the releasing process of lidocaine from the gel. The sol-gel transition temperature was decreased by increasing the polymer concentration and by the presence of additives. The rheological behaviour of Poloxamer gels characterized in this work can be useful for understanding further studies of drug release.

Chemistry, Pharmaceutical↗
PubMed1996

Isolation of two new antiinflammatory biflavanoids from Sarcophyte piriei.

Two new flavano flavanone glycosides, diinsininol (1) and diinsinin (2), have been isolated from the rhizome of Sarcophyte piriei, together with one known flavanone glycoside, naringenin 5-glucoside. Their structures were elucidated on spectroscopic evidence as 5,7,3',4'-tetrahydroxyflavanyl-7-O-beta-glucosyl-(4beta-8; 2beta-O-7)-eriodietyol (1) and 5,7,3',4'-tetrahydroxyflavanyl 7-O-beta-glucosyl-(4beta-8;2beta-O-7)-naringenin (2), respectively. The compounds were tested for their ability to inhibit prostaglandin synthesis, with 1 and 2 giving IC50 values of 9.20 microM and 13.14 microM, respectively, and in the inhibition of platelet-activating-factor-induced exocytosis, IC50 values of 49 and 39 microM.

Animals↗
PubMed1991

Microperfusion of sheep bronchioles.

We isolated segments of sheep bronchioles (length 406 +/- 46 microns, diameter 227 +/- 53 microns, n = 27). These segments were placed in a 37 degree C bath and cannulated at both ends with glass micropipettes. The proximal end was cannulated and held by three concentrically arranged micropipettes that delivered perfusion solution by gravity. The distal end was cannulated and held by two concentrically arranged micropipettes for fluid collection. When both the lumen and the bath contained oxygenated Krebs-Henseleit buffer (pH 7.40), spontaneous potential difference (PD) was 2.46 +/- 0.39 mV, lumen negative. KCN in the bath diminished PD by 1.48 +/- 0.29 mV (P = 0.00003, n = 25). The isolated bronchiole was depolarized when the luminal solution was Na free (delta PD -1.78 +/- 0.11 mV, P = 0.00007, n = 5) or when the submucosal bath was Cl free (delta PD -2.63 +/- 0.81, P = 0.018, n = 7). In preparations pretreated with 10 microM indomethacin, 1 microM isoproterenol raised PD by 0.75 +/- 0.29 mV (P = 0.03, n = 8), whereas 0.1 mM submucosal bumetanide reduced PD by 0.21 +/- 0.04 mV (P = 0.0005, n = 8). The data show that microperfusion technique is applicable for investigating ion transport by distal bronchioles and that the bronchiolar epithelium probably has both Na and Cl conductive pathways.

Acetazolamide↗
PubMed1989

Serological evidence of dengue fever among refugees, Hargeysa, Somalia.

Epidemics of a malaria-like illness affected several thousand residents of the Dam Camp, a refugee camp near Hargeysa in Somalia, during 1985, 1986, and 1987. The disease was characterized by fever, chills, sweats, headache, back and joint pains for as long as 10 days in some patients. Blood smears from acutely ill patients were negative for malaria. Of 28 acute and 10 convalescent sera tested by the indirect fluorescent antibody (IFA) and by the hemagglutination inhibition (HI) tests, all were negative for antibody to Rift Valley fever, Crimean-Congo hemorrhagic fever, Sindbis, Chikungunya, yellow fever, and Zika viruses. However, antibody reactive to dengue 2 virus was detected by the IFA test in 39% (15/38), and 11 of 29 (38%) of the same sera were antibody positive by the HI test. Also, IgG antibody reactive to dengue 2 was demonstrated in 60% (17/28) of the same sera by the enzyme immunoassay (EIA), and 14% (4/28) were positive for IgM antibody. Of ten patients for which acute and convalescent sera were available, two developed four fold or greater rises in antibody titer evidencing infection. These data suggested that dengue virus may have been the cause of the epidemic among the Dam Camp refugees.

Antibodies, Viral↗
PubMed1987

Histopathologic and immunohistopathologic features of subretinal fibrosis and uveitis syndrome.

We studied histopathologic and immunohistopathologic features of an eye from a patient who had hypopigmented choroidal lesions with subsequent development of progressive subretinal fibrotic tissue associated with minimal signs of vitreal inflammation. A 24-year-old woman had a rapid and severe onset of the disease, which led to blindness within a few months despite treatment with corticosteroids and cyclophosphamide. Histopathologic studies disclosed a marked gliotic retina and thick subretinal fibrotic tissue as well as a granulomatous lymphocytic infiltration in the choroid. Electron microscopy demonstrated that the subretinal tissue was derived from retinal pigment epithelial cells. The immunoperoxidase staining showed similar proportions of T and B lymphocytes, indicating a relative increase of B cells. There was a predominance of the helper/inducer T lymphocyte subset in the infiltrating area. The Müller cells in the retina expressed class II antigens of the major histocompatibility complex.

Adult↗
PubMed1985

Two visual systems in mental imagery: dissociation of "what" and "where" in imagery disorders due to bilateral posterior cerebral lesions.

We studied two patients with impaired visual perception and imagery caused by bilateral posterior cerebral lesions. The first had prosopagnosia and achromatopsia, and the imagery disorder involved the description of objects from memory, especially faces and animals, and colors of objects. The second had visual disorientation; the imagery problem involved the description of spatial relations from memory. Impairments of visual imagery, like disorders of visual perception, can be dissociated. Object and color imagery may be dissociated from imagery for spatial relations. A given imagery deficit tends to be associated with the corresponding type of perceptual deficit.

Adolescent↗
PubMed1981

[Sodium and potassium content of various Chilean foods].

Sodium and potassium contents of 40 high-protein dietary products were determined in order to complete the Table de Composición Química se Alimentos Chilenos (Chemical Composition Table of Chilean Foods). These cations' level must be strictly controlled in diets of many renal and heart patients. In Chile, Nutritionists who are in charge of preparing these diets, do not have a national composition table related to the sodium and potassium content for most of the food products. Samples of fluid cow's milk, dried milk with different fat contents, some cheeses, hen eggs, bovine entrails, some meat derivates and several meat cuts, including bovine, pork, lamb and chicken were studied.

Animals↗