Fahad J. Al-Shammary

Plasmid profile and antibiotic resistance in coagulase-negative staphylococci isolated from polluted water.

Four different species of coagulase‐negative staphylococci (CNS) were isolated from polluted waters in Fez, Morocco and found to be Staphylococcus simulans, Staph. lenticus, Staph. hyicus and Staph. xylosus. Eight isolates belonging to these four species were analysed for their plasmid content. Southern blot hybridizations were performed to define the resistance determinants of the plasmids harboured by these species. These determinants were found to be carried mainly by Class I staphylococcal plasmids (1–5 kb). A plasmid (4·3 kb) carrying a tetracycline resistance gene was present in five isolates from all identified species. Plasmids carrying a chloramphenicol resistance gene were more frequently encountered and found to be of different sizes. Plasmids carrying erythromycin, neomycin, and streptomycin resistance genes were less frequent and were the same size. The results indicate that the occurrence of multi‐resistant CNS in polluted waters may constitute a reservoir for disseminating antibiotic‐resistance into the community.

Determination of lomefloxacin in biological fluids by high-performance liquid chromatography and a microbiological method

A high‐performance liquid chromatographic method (HPLC) was developed for the determination of lomefloxacin in plasma and urine and was compared to a microbiological assay. Lomefloxacin and norfloxacin (internal standard) were extracted from plasma and urine samples using chloroform. Measurements were carried out with a fluorescence detector using an excitation wavelength of 280 nm and an emission wavelength of 430 nm with a mercury lamp. Quantification was achieved by the measurement of the peak‐height ratio and the analytical recovery of the drug from plasma and urine was found to be (mean±SD) 99·3 ± 3·74% and 95·7%±3·82%, respectively. In the microbiological assay, E. coli ATCC 1346 was the test organism using an agar diffusion technique. The coefficients of variation for within‐day analysis for both the HPLC method and microbiological assay from plasma samples were less than 7%. The minimum detectable concentration for both the HPLC and the microbiological method was 50 ng/ml and 100 ng/ml, respectively. Both methods were used to determine the lomefloxacin level in plasma following intravenous administration to mice. Excellent agreement was obtained between the results of the two methods. The HPLC method offers significant advantages in accuracy, precision, speed of analysis and turnover‐time.

GB virus C/Hepatitis G virus infection in Saudi Arabian blood donors and patients with cryptogenic hepatitis

Summary. Viral hepatitis is a common infection in the developing countries. Aside from Hepatitis A–E viruses, a novel hepatitis virus termed GBV-C, or HGV, was recently described. We have studied the prevalence of this virus among Saudi Arabian healthy blood donors (n = 200) and patients with cryptogenic (non-A–E) hepatitis (n=71). After serum extraction and RNA reverse transcription, amplification was carried out by the polymerase chain reaction (PCR), using primers for the 5′ noncoding region (NCR), NS5A region and NS3 helicase region. Among the patients with cryptogenic hepatitis, PCR-positivity was 18/71 (25.4%) for the 5′ NCR, 14/71 (19.7%) for the NS5A region, and 15/71 (21.1%) for the NS3 helicase region. Among the healthy blood donors, PCR-positivity was 4/200 (2%) for the 5′ NCR, 0/200 (0%) for the NS5A region, and 1/200 (0.5%) for the NS3 helicase region. Since the 5′ NCR is considered the most conserved segment of the virus genome, it is not unusual to find higher positivity rate when that region is used for amplification. It is noted that the positivity rate is not far different among the three amplified regions, indicating that the heterogeneity of GBV-C/HGV is not as extensive as in hepatitis C virus. Phylogenetic analysis of 5′NCR DNA sequences showed that all isolates in this study belong to genotype 2. We conclude that the prevalence of GBV-C/HGV is similar to what is reported worldwide among the general Saudi population but relatively higher among Saudi patients with cryptogenic hepatitis.

Leishmania infecting man and wild animals in Saudi Arabia. 9. The black rat (Rattus rattus) a probable reservoir of visceral leishmaniasis in Gizan province, south-west Saudi Arabia

Twenty-two black rats (Rattus rattus) were captured in houses where parasitologically confirmed cases of human visceral leishmaniasis had been recorded in Al-Arda Emara, Gizan province, south-west Saudi Arabia. Four of the rats were found to be infected with Leishmania; isoenzyme characterization showed that 3 were infected with L. donovani sensu lato zymodeme LON42 and the fourth with L. infantum zymodeme LON49. L. donovani s.l. LON42 has also been isolated from human visceral leishmaniasis patients living in this area, while dogs, but not humans, have been found to be infected with L. infantum LON49 in this part of Saudi Arabia.

Production of superoxide anion by polymorphonuclear leukocytes from diabetic patients with or without diabetic retinopathy

Oxygen free radicals have been implicated in the pathogenesis of diabetic microangiopathy. The production of superoxide anion (O2−.) by polymorphonuclear leukocytes (PMNs) from 45 insulin-dependent diabetes mellitus patients in the resting state and in response to a soluble stimulus (phorbol myristate acetate) was measured spectrophotometrically and compared with that of 15 age and sex matched controls. The resting superoxide anion production by PMNs from diabetic patients was significantly higher than that of controls (2.17 ± 1.32 and 1.35 ± 0.6 nmol/105 cells/60 min respectively; p=0.037). In contrast, PMNs from diabetic patients released significantly lower levels of superoxide anion compared to controls in response to phorbol myristate acetate stimulation (2.33 ± 2.04 and 3.55 ± 0.98 nmol/105 cells/60 min respectively; p = 0.044). The stimulated superoxide anion production was significantly higher in diabetic patients with retinopathy compared to diabetic patients without retinopathy (2.71 ± 2.08 and 1.3 ± 1.6 nmol/105 cells/60 min respectively; p = 0.02). Furthermore, stimulated PMNs from diabetic patients with proliferative retinopathy generated superoxide anion at significantly higher rates than did those from diabetics with nonproliferative retinopathy or without retinopathy (3.8 ± 1.5, 2.08 ± 2.1 and 1.3 ± 1.6 nmol/ 105 cells/60 min respectively; p= 0.005). These results suggest that reactive oxygen species produced by PMNs may play a role in the progression of diabetic retinopathy.

Leishmania major: in vitro ultrastructural study of the paraxial rod of promastigotes.

The flagellum of Leishmania major promastigotes has an intraflagellar structure known as the paraxial rod (PAR) which extends from a point halfway in the flagellar pocket to the tip of the flagellum, lying opposite the axonemal microtubule doublets 4-7. An expansion of the axonemal plasma membrane envelops the PAR and may provide desmosomal attachment at the orifice of the flagellar pocket. The complex organization of the 4-6 nm thick filaments in the PAR was studied by us in cross, oblique, longitudinal and tangential sections by electron microscope. These filaments are disposed in two parallel lamellae, one alongside the axoneme (ca. 45 nm thick), and the other alongside the plasma membrane (ca. 65 nm thick), with an interlamellar gap of about 22-28 nm. In each lamella, 8-12 parallel series of longitudinal filaments at ca. 30 nm intervals interdigitate with coplanar parallel series of oblique filaments at ca. 25 nm intervals and inclined to the long axis of the flagellum at ca. 48 degrees, and ca. 55 degrees, in the inner (paraxonemal) and outer lamella, respectively. The parallel filaments in each of the longitudinal and oblique series are spaced at ca. 8 nm intervals. They are cross-striated at ca. 30 nm intervals by transverse filaments which terminate occasionally on adjacent axonemal microtubules 5 and 6 in the inner lamella, and the plasma membrane in the outer lamella. Extending across the interlamellar gap is a set of parallel rows of 7-12 nearly parallel filaments at ca. 20 nm intervals. The part of the flagellar plasma membrane enclosing the PAR has a subplasmalemmal cytoskeleton consisting of a layer of longitudinal 2 nm filaments at 8 nm intervals, obliquely striated by parallel 2 nm filament doubles at ca. (-65) degrees with the long axis of the flagellum and ca. 20 nm periodicity. Each filament doublet stria apparently gives origin to collinear short filament doublet extensions that curve into juxtaposed meshes of the outer lamella. Microtubules of the axonemal doublets 5 and 6 are connected to electron-dense (ca. 12 nm thick) strips of the inner lamella of the PAR by longitudinal series of ca. 4 nm cross-links across a ca. 12 nm cleft.

Analytical Profile of Furosemide

Publisher Summary This chapter discusses the analytical profile of furosemide. Its generic names are frusemide, fursemide, aisemide, beronald, desdemin, diural, dryptal, errolan, and mita. It is a white to slightly yellow in color, odorless, almost tasteless crystalline powder. Its melting range is 206°C. It is slightly soluble in water and chloroform and ether. It is soluble in acetone, methanol, dimethyl formamide and in solutions of alkali hydroxides. Furosemide injection should be stored at temperature of 15-3O°C and protected from light, injections having yellow color should not be used. Exposure of furosemide tablets to light may cause discoloration; discolored tablets should not be dispensed. Tablets should be stored and dispensed in well closed, light resistant containers.

Serum factor from diabetic patients with or without retinopathy stimulates superoxide anion production by normal polymorphonuclear leukocytes

Oxygen free radicals (OFRs) have been implicated in the pathogenesis of diabetic microangiopathy. The effects of serum from insulin-dependent diabetes mellitus patients with or without retinopathy on the production of superoxide anion by normal polymorphonuclear leukocytes (PMNs) were measured spectrophotometrically and compared with that of age matched controls. Superoxide anion production by PMNs incubated with serum from retinopathy-free patients or patients with retinopathy was significantly higher than that of controls (P=0.0002 and 0.0001, respectively). Furthermore, superoxide anion production by PMNs incubated with serum from patients with retinopathy was significantly higher than retinopathy-free patients (P=0.02). These observations suggest that a diabetic serum factor provoked a significant generation of superoxide anion in normal PMNs, a phenomenon found parallel to the presence of retinopathy, indicating that OFRs may play a role in the progression of diabetic retinopathy. The nature of this serum factor remains to be clarified.

Analytical Profile Of Folic Acid

Publisher Summary This chapter discusses the analytical profile of folic acid. The generic names of folic acids are: acidum; cytofol; folsavre; folacin; foldine; folaemin; foliamin; folicet; folipac; foletts; and folsan. It appears in a yellowish to orange in color, in the form of crystalline powder, almost odorless, tasteless microcrystalline powder, containing 5 to 8.5% of H 2 O. It is very slightly soluble in cold water, soluble to about 1% in boiling water; slightly soluble in methanol, appreciably less soluble in ethanol and butanol; insoluble in acetone, chloroform, ether, and benzene; relatively soluble in acetic acid, phenol, pyridine, solutions of alkali hydroxides and carbonates. It is soluble in hot diluted HC1 and H 2 S0 4 . It is soluble in HC1 and H 2 S0 4 yielding very pale yellow solutions. Folic acids are widely distributed in plants, animals and microorganisms. Donald Mastropaolo et al reported the crystal structure of folic acid. A stereoscopic view of the molecule shows folic acid to be an extended conformation. Folic acid is absorbed rapidly from the GI tract following oral administration; the vitamin is absorbed mainly from the proximal portion of the small intestine.

Analytical Profile of Thiamine Hydrochloride

Publisher Summary This chapter discusses the analytical profile of thiamine hydrochloride. Its generic names are thiamine hydrochloride and vitamin B1. Its trade names are vitamin B hydrochloride, thiamine chloride hydrochloride, aneurine hydrochloride, and thiaminium-chloride. Its molecular weight is 337.25. It is colourless crystals or white crystalline powder with a characteristic somewhat meat-like odor and a bitter taste. It occurs in plants and in animal tissues, notably in rice husk, cereal grains, yeast, liver, eggs, milk, green leaves, roots and rice bran. Its melting range is 248° with decomposition. Its one gram dissolves in about 1 ml of water, 18 ml glycerol, 100 ml 95% alcohol, 315 ml abs. alcohol, more soluble in methanol soluble, in propylene glycol. It is practically insoluble in ether, benzene, hexane, chloroform.