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At least 163 records · Page 9Linked to original sources
PubMed2005

Mass spectrometric study to characterize thioisoindole derivatives of aminoglycoside antibiotics.

Aminoglycoside antibiotics are widely used to treat serious Gram-negative and Gram-positive bacterial infections. The lack of a UV chromophore presents a problem in the analysis of aminoglycosides. Derivatization with 1,2-phthalic dicarboxaldehyde (OPA) in the presence of a thiol made it possible to introduce a UV chromophoric thioisoindole moiety. A qualitative mass spectrometry study was carried out to confirm the molecular identity of the products formed. The conditions described earlier to derivatize gentamicin and kanamycin yielded products in which all primary amino groups are fully derivatized. On the other hand, with tobramycin and amikacin, there was also formation of incompletely derivatized products that contained one thioisoindole group less than the fully derivatized product. This study has therefore brought an additional insight into the nature of the OPA-aminoglycoside derivatives studied.

Aminoglycosides↗
PubMed2001

Analysis of synthetic chemical drugs in adulterated Chinese medicines by capillary electrophoresis/electrospray ionization mass spectrometry.

Sixteen synthetic chemical drugs, often found in adulterated Chinese medicines, were studied by capillary electrophoresis/UV absorbance (CE/UV) and capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS). Only nine peaks were detected with CZE/UV, but on-line CZE/MS provided clear identification for most compounds. For a real sample of a Chinese medicinal preparation, a few adulterants were identified by their migration times and protonated molecular ions. For coeluting compounds, more reliable identification was achieved by MS/MS in selected reaction monitoring mode. Micellar electrokinetic chromatography (MEKC) using sodium dodecyl sulfate (SDS) provided better separation than capillary zone electrophoresis (CZE), and, under optimal conditions, fourteen peaks were detected using UV detection. In ESI, the interference of SDS was less severe in positive ion mode than in negative ion mode. Up to 20 mM SDS could be used in direct coupling of MEKC with ESI-MS if the mass spectrometer was operated in positive ion mode. Because of better resolution in MEKC, adulterants can be identified without the use of MS/MS.

Anti-Inflammatory Agents↗
PubMed2000

Resistance of vaccinia virus to inactivation by solvent/detergent treatment of blood products.

The inactivation of enveloped viruses by two different solvent/detergent combinations, i.e. tri-n-butyl phosphate (TNBP)/Triton X-100 or TNBP/Tween 80, has been investigated using a high purity factor VIII (Replenate) and factor IX (Replenine) respectively. Treatment with TNBP/Triton X-100 rapidly inactivated all the typical enveloped viruses tested, i.e. Sindbis, semliki forest virus (SFV), herpes simplex virus type-1 (HSV-1) and vesicular stomatitis virus (VSV), by 3.7-5.8 log within 15 seconds. While virus inactivation with TNBP/Tween 80 was slower, effective inactivation of Sindbis, HSV-1, VSV and human immunodeficiency virus type-1, i.e. 4.1-->6.3 log, occurred within 30 minutes. In contrast, vaccinia virus was relatively resistant to inactivation in either of these solvent/detergent combinations. Incubation times of 10 minutes for TNBP/Triton X-100 or 6-24 hours for TNBP/Tween 80, were required to reach inactivation levels of about 4 log.

Animals↗
PubMed1981

Effects of polychlorinated terphenyls and paraffins on rat liver microsomal cytochrome P-450 and in vitro metabolic activities.

The polychlorinated terphenyl Aroclor 5460 and the polychlorinated paraffins Witaclor 171 P and Witaclor 149 increased to different degrees the total microsomal concentration of cytochrome P-450 in the rat liver after intraperitoneal injection of 0.3, 1.0, and 1.0 g . kg-1 body weight, respectively, each day for four days. The multiple forms of cytochrome P-450 were affected differently with an induction of RLvMc P-450(50) and RLvMc P-450(54) by all chemicals, and an additional induction of RLvMc P-450(55) by the polychlorinated terphenyl. The rat liver weights were extensively increased after treatment with the polychlorinated paraffins. Alterations were found in the in vitro metabolism of biphenyl, benzo(a)pyrene and the steroid hormones, 4-androstene-3,17-dione and 5 alpha-androstane-3 alpha, 17 beta-diol, after exposure to all chemicals. Changes in the in vitro formation of benzo(a)pyrene metabolites were found to correlate with changes in the multiple forms of cytochrome P-450. The present study demonstrate that only limited information can be obtained from alterations in the total concentration of cytochrome P-450 and show the importance of studying changes in the multiple forms and the metabolism of different substrates. Our results further indicate that exposure to any of the investigated polychlorinated chemicals may alter the biological effects of other environmental contaminants, drugs and endogenous substances which are metabolized by the cytochrome P-450 enzyme system.

Animals↗
PubMed1977

Carcinogenicity of trichloroethylene: fact or artifact?

Technical trichloroethylene has been found carcinogenic in mice after high daily doses per os. A GC-MS analysis of this technical sample revealed the presence of considerable amounts of epichlorohydrin and 1.2-epoxibutane as stabilizers. These epoxides are highly mutagenic in the Ames test and are, most probably, responsible for the carcinogenic effect found in mice. The question whether trichloroethylene is carcinogenic or not remains open.

Carcinogens↗
PubMed1991

Toxigenic Aspergillus flavus and aflatoxins in Sri Lankan medicinal plant material.

The fungal flora of 6 Asian medicinal plants, Aerva lanata (Linn.) Juss. Alyssicarpus vaginalis D.C., Tribulus terrestris Linn. Adhatoda vasica Nees., Centella asciatica (L.) Urb., Cardiospermum halicacabum Linn. was determined. After surface disinfection Aspergillus spp. were most frequently observed. Aspergillus flavus, isolated from Alyssicarpus vaginalis and Aerva lanata produced aflatoxins in culture. Aflatoxin B1 was also detected in a sample of Aerra lanata at a level of 0.5 micrograms/g. Plant material destined for medicinal use should be stored carefully prior to its use to prevent growth of naturally occurring toxigenic mold fungi.

Aflatoxins↗
PubMedDate not supplied

Fungi associated with herbal drug plants during storage.

Samples of sundried herbal drug plant parts stored for sale were purchased from four herbal markets located in Ibadan, Nigeria. The plant parts were analysed for mycoflora associated with their storage. Fungal colony counts ranged from 0.60 x 10(2) to 3.50 x 10(2) within the period of the survey. Twenty eight fungal species were isolated with the species of Aspergillus niger, A. flavus, Fusarium moniliforme, Trichoderma viride, Penicillium expansum and Mucor fragilis being the dominant ones. There were marked differences between the flora obtained on fresh plant parts and those stored for sale. The results obtained showed that herbal drug plant pieces stored for sale in the markets are hazardous for human health. There is therefore the need for some form of quality control and decontamination before they are used for herbal drug preparations.

Aspergillus↗
PubMed1977

Agranulocytosis during treatment with chlozapine.

Within six months of the introduction of the new antipsychotic drug clozapine in Finalnd, 17 cases of neutropenia or agranulocytosis were recorded amongst about 3000 patients treated. Agranulocytosis was fatal in eight patients, and in addition, two patients developed thrombocytopenia, and one patient leukaemia. As additional cases might well have been overlooked as banal infections, the risk of developing agranulocytosis during clozapine treatment was at least 0.5%. Impaired elimination of the drug or increased susceptibility of granulocyte precursors to clozapine, possibly due to some inherited characteristic, might explain the high incidence of complications.

Adolescent↗
PubMed1985

Misoprostol preclinical pharmacology.

Misoprostol, a synthetic derivative of prostaglandin E1, was tested and shown to be an effective gastric antisecretory agent against histamine-, pentagastrin-, and meal-stimulated acid secretion in dogs. Misoprostol reduced the volume of acid secretion as well as the hydrogen ion concentration. Misoprostol did not reduce gastric mucosal blood flow, nor did it alter meal-stimulated serum gastrin levels. Misoprostol inhibited acid secretion in histamine-stimulated isolated gastric glands indicating a direct antisecretory effect on parietal cells. The potency of misoprostol was greatest when administered in direct contact with the gastric mucosa indicating local absorption and action. Misoprostol strengthened the gastric mucosal barrier as shown by the attenuation of aspirin-induced lowering of transmucosal electrical potential differences. Misoprostol protected the gastric mucosa of rats subjected to ethanol-, taurocholate-, pyloric ligation-, stress- and indomethacin-induced damage. Misoprostol also protected against indomethacin-induced intestinal lesions in rats and reduced duodenal ulcer formation in guinea-pigs and cats. The doses of misoprostol required to protect against gastric damage were about one-tenth of those required to inhibit acid secretion. The results of these and other studies indicate that misoprostol is a safe agent with unique properties that should provide a new approach for treatment of ulcer diseases of the gastrointestinal tract.

Airway Resistance↗
PubMed1994

The preservation of some oral liquid preparations. The replacement of chloroform by other preservatives.

Chloroform should be considered as an obsolete preservative for pharmaceutical preparations, because of its toxicological implications and its physical instability. The effectiveness of possible alternatives for chloroform in three oral liquid pharmaceutical preparations was investigated, using a microbiological challenge test. Magnesium trisilicate mixture (British Pharmacopoeia) can be adequately preserved with methylparaben (2 g/l). Only insignificant amounts of methylparaben were absorbed by the solids present in the magnesium trisilicate mixture. Ferrous sulfate mixture (British Pharmacopoeia) can be preserved with a mixture of methylparaben (1.8 g/l) and propylparaben (0.2 g/l). Sorbic acid (1 g/l) is a suitable preservative for promethazine hydrochloride syrup.

Administration, Oral↗
PubMed1995

Hepatitis E probably contracted via a Chinese herbal medicine, demonstrated by nucleotide sequencing.

Hepatitis E is endemic in developing countries and may occur as imported hepatitis in industrialized countries. A 46-year-old Japanese man developed immunoserologically diagnosed acute hepatitis E in Japan 4 months after he had made a trip to China. He had bought a Chinese herbal medicine there, taking it occasionally until approximately 6 weeks prior to the onset of acute hepatitis. Nucleotide sequencing of the 3' terminal region of the viral cDNA amplified from the patient's serum by polymerase chain reaction revealed a high degree of homology (99.8% of 752 nucleotides) with the Chinese strain. Thus, the results of sequencing suggest that his hepatitis E was caused by infection with the Chinese strain, via the Chinese herbal medicine.

Acute Disease↗
PubMedDate not supplied

A survey of the quality of generic clarithromycin products manufactured in Slovenia and Israel.

This study evaluated the quality of 11 generic clarithromycin products obtained in Poland, Slovakia, Slovenia, or Israel and manufactured in Slovenia or Israel. The generic products were examined visually, assayed by high-pressure liquid chromatography for clarithromycin content and impurities, tested for dissolution properties, and compared with the innovator product manufactured by Abbott Laboratories. Fifty-five percent of generic products fell short of the specifications for the innovator product. Ten percent of the generic products did not contain the amount of clarithromycin claimed in the label; 18% released less drug than did the branded tablets in the standard dissolution assay. In light of these results, it is not possible to conclude that all generic tablets are of the same quality as the innovator product; clinical trial results achieved with branded clarithromycin should not be extrapolated to generic products.

Anti-Bacterial Agents↗