PubMed Health⌕ Search

Biomedical subjects

S L Ali

Publications and source records attributed to S L Ali.

12 recordsLinked to original sources
PubMed2006

Tail hair as an indicator of environmental exposure of cows to lead and cadmium in different industrial areas.

This study examines the use of tail hair from cows as a possible biomarker of environmental exposure to lead and cadmium around different industrial areas. Respective blood and tail hair samples were collected from a total of 317 apparently healthy cows above 3 years of age. This includes 287 cows reared in industrial and urban areas and 30 cows from areas free from polluting sources. Significantly (P<0.05) higher lead and cadmium residues were recorded in hair from cows reared around lead-zinc smelter and closed lead cum operational zinc smelter. However, cows from those areas had significantly (P<0.05) higher blood lead but not cadmium concentration as compared to respective control value. Although mean blood lead concentration in cows around aluminum processing plant and urban cum small industrial areas and that of cadmium around steel processing plant were significantly (P<0.05) higher than respective control, the mean hair lead and cadmium content remained statistically (P>0.05) comparable to that of respective control values. The blood lead was significantly correlated with hair lead (r = 0.672, P<0.01) and cadmium (r = 0.309, P<0.05). There was a significant correlation between lead and cadmium concentration (r = 0.610, P<0.01) in hair and a nonsignificant correlation between blood and hair cadmium suggesting that cadmium accumulation in hair was influenced by blood and hair lead concentrations in cows environmentally exposed to lead.

Animals↗
PubMed1996

Biotransformation of aflatoxin B1 in human lung.

In addition to being a potent hepatocarcinogen, aflatoxin B1 (AFB1) is a pulmonary carcinogen in experimental animals, and epidemiological studies have shown an association between AFB1 exposure and lung cancer in humans. This study investigated AFB1 bioactivation and detoxification in human lung tissue obtained from patients undergoing clinically indicated lobectomy. [3H]AFB1 was bioactivated to a DNA binding metabolite by human whole lung cytosols in a time-, protein concentration-, and AFB1 concentration-dependent manner. Cytosolic activation of [3H]AFB1 correlated with lipoxygenase (LOX) activity and was inhibited by the LOX inhibitor nordihydroguaiaretic acid (NDGA; 100 microM), indicating that LOXs were largely responsible for the observed cytosolic activation of AFB1. In whole lung microsomes, low levels of indomethacin inhibitable prostaglandin H synthase (PHS)-mediated [3H]AFB1-DNA binding and cytochrome P-450 (P450)-mediated [3H]AFB1-DNA binding were observed. Cytosolic glutathione S-transferase (GST)-catalyzed detoxification of AFB1-8,9-epoxide, produced by rabbit liver microsomes, was minimal at 1 and 10 microM [3H]AFB1. With 100 microM [3H]AFB1, [3H]AFB1-8,9-epoxide conjugation with reduced glutathione was 0.34 +/- 0.26 pmol/mg/h (n = 10). In intact, isolated human lung cells, [3H]AFB1 binding to cellular DNA was higher in cell fractions enriched in macrophages than in either type II cell-enriched fractions or fractions containing unseparated cell types. Indomethacin produced a 63-100% decrease in [3H]AFB1-DNA binding in macrophages from five of seven patients, while NDGA inhibited [3H]AFB1-DNA adduct formation by 19, 40 and 56% in macrophages from three of seven patients. In alveolar type II cells, NDGA decreased [3H]AFB1-DNA binding by 30-100% in cells from three patients and indomethacin had little effect. SKF525A, an isozyme non-selective P450 inhibitor, enhanced [3H]AFB1 binding to cellular DNA in unseparated cells, macrophages, and type II cells, suggesting that P450-mediated bioactivation of AFB1 is not a major pathway by which AFB1-8,9-epoxide is formed in human lung cells. Overall, these studies suggest that P450 has a minor role in the bioactivation of AFB1 in human lung. Rather, LOXs and PHS appear to be important bioactivation enzymes. Co-oxidative bioactivation of AFB1, in combination with the low conjugating activity displayed by human lung cytosolic GSTs, likely contributes to human pulmonary susceptibility to AFB1.

Aflatoxin B1↗
PubMed1996

[The relative bioavailability of paracetamol in suppositories in comparison to tablets].

Relative Bioavailability Studies on Paracetamol in Suppositories as Compared to Tablets. Relative bioavailabilities of 250 mg paracetamol (CAS 103-90-2) in ben-u-ron 125 mg and ben-u-ron 250 mg suppositories were determined in comparison with that of cut-in-half Benuron tablets 500 mg in an open intraindividual 3-period-changeover-study in 18 healthy volunteers. Plasma concentrations of paracetamol were analyzed by means of a specific and sensitive HPLC-method with UV-detection. For the assessment of the bioavailability AUC, Cmax, tmax and HVD (half value duration) were used as pharmacokinetic characteristics. Relative bioavailability of paracetamol was 102% for 125 mg and 93% for 250 mg suppositories, compared with that of cut-in-half 500 mg tablets. Mean maximum paracetamol plasma concentrations (Cmax) were determined as 2.1 micrograms/ml (CV = 31%; (CV = Coefficient of Variation), 2.0 micrograms/ml (CV = 27%) and 3.5 micrograms/ml (CV = 27%) after administration of 125 mg and 250 mg suppositories and 500 mg cut-in-half tablets, respectively. These maximum concentrations were achieved 2.2 +/- 0.7, 1.8 +/- 0.7 and 0.6 +/- 0.3 h (tmax) after administration of the respective preparations. The corresponding HVD-values were 3.8 +/- 1.0, 3.5 +/- 0.9 and 1.8 +/- 0.8 h, respectively. Extent of bioavailability of paracetamol (dose: 250 mg) following administration of 125 mg as well as 250 mg suppositories in comparison with 500 mg tablets was shown to be equivalent. The results obtained in this study confirm the adequate bioavailability of both suppositories compared with tablets. On the other hand both suppository preparations were assessed as being bioequivalent concerning AUC and Cmax.

Acetaminophen↗
PubMed1994

[Relative bioavailability of paracetamol in suppositories preparations in comparison to tablets].

Relative Bioavailability of Paracetamol as Suppositories Compared to Tablets. The relative bioavailability of paracetamol (CAS 103-90-2) in ben-u-ron 500 mg and ben-u-ron 1000 mg suppositories (test formulations) was compared with that of Benuron tablets 500 mg (reference product) in an open, intraindividual, 3-period-changeover-study in 18 healthy subjects. Plasma concentrations of paracetamol were determined using a specific and sensitive HPLC method with UV detection. For the assessment of bioavailability AUC, Cmax, tmax and HVD were used as pharmacokinetic characteristics. Bioequivalence of the rectal formulations was tested by calculating 90% confidence intervals using the Two-one-sided-t-tests-procedure and log-transformed data of AUC and Cmax. For AUC the confidence intervals were required to be in the 80 and 125% range, for Cmax between 70 and 143% (inclusion rule). Data from 17 subjects could be evaluated. Bioavailability of paracetamol was 89 and 90% for the 500 and 1000 mg suppositories, respectively compared with that of the 500 mg reference tablets. Mean maximum paracetamol plasma concentrations (Cmax) were 3.55 and 6.02 or 7.16 mg/l after administration of the 500 and 1000 mg suppositories or the 500 mg tablets, respectively. These maximum concentrations were achieved 2.0, 2.7 and 0.6 h (tmax) after administration of the respective preparations. The corresponding HVD values were 4.3, 5.2 and 2.0 h, respectively. After dose adjustment of the results for the 1000 mg suppositories relative bioavailabilities of paracetamol from both rectal formulations exceeded 80% of that from the tablets.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗
PubMed1987

Determination of chlormezanone in human plasma after administration of chlormezanone formulations.

In the course of a bioavailability study some 800 plasma samples were analysed by means of HPLC after administration of 5 different chlormezanone formulations to 10 healthy male volunteers. A metabolic product of chlormezanone (I) could not be detected in any of the samples. The results were further verified through mass spectrometric measurements of chlormezanone, extracted from the plasma sample and separated through HPLC, in off-line mode. Chlormezanone is found as an intact molecule in human plasma samples.

Adult↗
PubMed1983

Atomic absorption spectrometry in pharmaceutical analysis.

A short review of the principles of atomic absorption spectrometry (AAS) - sources, atomizers, background correction, instrumentation, sample preparation, sensitivity, limit of detection, etc. - is given. The technique can be applied for impurity tests for trace metals as well as for assay of various commonly occurring elements in pharmaceuticals. The application of AAS in pharmaceutical analysis is illustrated with 17 examples.

Journal Article↗
PubMed1976

Application of gas-liquid chromatography and high-performance liquid chromatography to the analysis of trace amounts of salicylic acid, acetylsalicylic anhydride and acetylsalicylsalicylic acid in aspirin samples and aspirin formulations.

The gas-liquid chromatographic (GLC) determination of salicylic acid (SA) in 12 commercial acetylsalicylic acid (aspirin, ASA) samples and 12 ASA formulations is reported. The GLC determination of SA as an impurity in ASA, utilising methylation with methyl iodide in the presence of potassium carbonate, requires a column chromatographic separation of SA prior to derivatization. Trace amounts of SA in ASA have also been determined by high-performance liquid chromatography (HPLC) on a Sil-X-I adsorption column using light petroleum-ethyl acetate-acetic acid as the mobile phase. Acetylsalicylic anhydride (ASN) and acetylsalicylsalicylic acid (ASSA) were determined by HPLC on a reversed-phase C18 column with water-methanol mixtures as the mobile phase. GLC was also applied to the determination of ASN as an impurity in ASA formulations.

Anhydrides↗