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Biomedical subjects

M Aslam

Publications and source records attributed to M Aslam.

At least 145 records · Page 8Linked to original sources
PubMed1986

Enhancement of nitrate uptake and growth of barley seedlings by calcium under saline conditions.

The effect of Ca2+ on NO3- assimilation in young barley (Hordeum vulgare L. var CM 72) seedlings in the presence and absence of NaCl was studied. Calcium increased the activity of the NO3- transporter under saline conditions, but had little effect under nonsaline conditions. Calcium decreased the induction period for the NO3- transporter under both saline and nonsaline conditions but had little effect on its apparent Km for NO3- both in the presence and absence of NaCl. The enhancement of NO3- transport by Ca2+ under saline conditions was dependent on the presence of Ca2+ in the uptake solution along with the salt, since Ca2+ had no effect when supplied before or after salinity stress. Although Mn2+ and Mg2+ enhanced NO3- uptake under saline conditions, neither was as effective as Ca2+. In longer studies, increasing the Ca2+ concentration in saline nutrient solutions resulted in increases in NO3- assimilation and seedling growth.

Biological Transport↗
PubMed1986

The clinical significance of metal binding in convulsion control with sodium valproate.

The facility with which certain metal salts of physiological importance can bind to the anticonvulsant drug, sodium valproate, is demonstrated. The products are characterized in vitro and the clinical significance of these findings are discussed in terms of the hair loss side-effect exhibited by some patients who are prescribed the drug for the treatment of epilepsy. The first reports are also given of preliminary in vivo data on the copper and zinc status of paediatric patients on sodium valproate.

Chemical Phenomena↗
PubMed1986

Compliance and drug therapy in fasting Moslem patients.

The effects of fasting on the drug regimens of 81 Asian Moslem patients during the religious month of Ramadan have been examined. Twenty-two male and 15 female patients were found to change their drug dosage pattern while fasting: 35 missed doses; 8 took their tablets at different times and 4 patients took all their medication as one single daily dose after breaking fast in the evening. The consequences of these changes are discussed and ways in which the problems which arise may be overcome are examined.

Adolescent↗
PubMed1986

Repeated membrane plasma separation with on-line sorbent treatment of plasma in the conscious rat.

Repeated membrane plasma separation with on-line sorbent treatment of plasma was performed in unrestrained and conscious rats, thus avoiding the possible effects of repeated stress and exposure to anesthetic agents. The procedure was well tolerated, even after four consecutive perfusions. Blood flow was 0.7 ml/min, with a transmembrane pressure of 18.6 mm Hg and plasma filtration rate of 0.21 ml/min. This allowed 12 ml of plasma (greater than 1 plasma volume) to be treated within 1 h. Levels of albumin, immunoglobulin G, and C3 remained constant during each perfusion and were not significantly different from those of animals subjected to control procedures. Results obtained from filtrate were comparable at 15 and 60 min with values obtained from whole blood, with sieving coefficients of approximately 1. Leukocyte, erythrocyte, and thrombocyte counts remained unchanged during each plasma perfusion. A progressive rise in leukocyte counts occurred following successive perfusions, but this was true also of animals subjected to control procedures.

Animals↗
PubMed1986

Preclinical evaluation of haemosorbents.

The selection of assessment procedures for the preclinical evaluation of haemosorbents and the relationship between such procedures and the intended application are exemplified by examination of the design and utilization of procedures based on the rat. Procedures are described for haemoperfusion and for membrane plasma separation followed by on-line sorbent treatment of plasma (plasma perfusion). These procedures are suitable for single or repeated use, with the animal in an unrestrained and conscious state. The relevance to the intended application is demonstrated with respect to artificial liver support by the ability of rat extracorporeal circuits to provide information on the relationship between sorbent properties and liver regeneration as determined by the proliferative response following partial hepatectomy.

Adsorption↗
PubMed1984

Dependency of Nitrate Reduction on Soluble Carbohydrates in Primary Leaves of Barley under Aerobic Conditions.

Nitrate reduction was studied as a function of carbohydrate concentration in detached primary leaves of barley (Hordeum vulgare L. cv Numar) seedlings under aerobic conditions in light and darkness. Seedlings were grown either in continuous light for 8 days or under a regimen of 16-hour light and 8-hour dark for 8 to 15 days. Leaves of 8-day-old seedlings grown in continuous light accumulated 4 times more carbohydrates than leaves of plants grown under a light and dark regimen. When detached leaves from these seedlings were supplied with NO(3) (-) in darkness, those with the higher levels of carbohydrates reduced a greater proportion of the NO(3) (-) that was taken up. In darkness, added glucose increased the percentage of NO(3) (-) reduced up to 2.6-fold depending on the endogenous carbohydrate status of the leaves. Both NO(3) (-) reduction and carbohydrate content of the leaves increased with age. Fructose and sucrose also increased NO(3) (-) reduction in darkness to the same extent as glucose. Krebs cycle intermediates, citrate and succinate, did not increase NO(3) (-) reduction, whereas malate slightly stimulated it in darkness.In light, 73 to 90% of the NO(3) (-) taken up was reduced by the detached leaves; therefore, an exogenous supply of glucose had little additional effect on NO(3) (-) reduction. The results indicate that in darkness the rate of NO(3) (-) reduction in primary leaves of barley depends upon the availability of carbohydrates.

Journal Article↗
PubMed1984

Early effects of salinity on nitrate assimilation in barley seedlings.

The effect of NaCl and Na(2)SO(4) salinity on NO(3) (-) assimilation in young barley (Hordeum vulgare L. var Numar) seedlings was studied. The induction of the NO(3) (-) transporter was affected very little; the major effect of the salts was on its activity. Both Cl(-) and SO(4) (2-) salts severely inhibited uptake of NO(3) (-). When compared on the basis of osmolality of the uptake solutions, Cl(-) salts were more inhibitory (15-30%) than SO(4) (2-) salts. At equal concentrations, SO(4) (2-) salts inhibited NO(3) (-) uptake 30 to 40% more than did Cl(-) salts. The absolute concentrations of each ion seemed more important as inhibitors of NO(3) (-) uptake than did the osmolality of the uptake solutions. Both K(+) and Na(+) salts inhibited NO(3) (-) uptake similarly; hence, the process seemed more sensitive to anionic salinity than to cationic salinity.Unlike NO(3) (-) uptake, NO(3) (-) reduction was not affected by salinity in short-term studies (12 hours). The rate of reduction of endogenous NO(3) (-) in leaves of seedlings grown on NaCl for 8 days decreased only 25%. Nitrate reductase activity in the salt-treated leaves also decreased 20% but its activity, determined either in vitro or by the ;anaerobic' in vivo assay, was always greater than the actual in situ rate of NO(3) (-) reduction. When salts were added to the assay medium, the in vitro enzymic activity was severely inhibited; whereas the anaerobic in vivo nitrate reductase activity was affected only slightly. These results indicate that in situ nitrate reductase activity is protected from salt injury. The susceptibility to injury of the NO(3) (-) transporter, rather than that of the NO(3) (-) reduction system, may be a critical factor to plant survival during salt stress.

Journal Article↗
PubMed1984

Lead-induced convulsions in young infants--a case history and the role of GABA and sodium valproate in the pathogenesis and treatment.

A detailed case history of lead poisoning in a young infant is presented. Attention is directed towards the nature of the induced convulsions observed in such cases and the possible role of the GABAergic neuroinhibitory system. In vitro data demonstrating direct lead-GABA interaction is presented and sodium valproate, an effective anticonvulsant which affects GABA function, is shown to be an appropriate agent for medication in lead-induced convulsions. The hypothesis is presented that lead interacts with GABA which thereby reduces the neuroinhibition and that this may be counteracted by the action of sodium valproate.

Chemical Phenomena↗
PubMed1984

Practical miniaturized membrane oxygenator for isolated organ perfusion.

Silastic membrane tubing oxygenators possess valuable atraumatic properties, but no satisfactory miniature system for isolated organ perfusion has been achieved. We describe the construction of a new type of miniaturized Silastic membrane tubing oxygenator, 1.5 m long, 1.5-mm diameter, 75-micron wall thickness, incorporated in a single self-supporting unit readily applicable to isolated organ perfusion because of its simplicity, durability, and small prime volume of less than 3 ml. In vitro experiments using out-dated human banked blood demonstrated that the unit can effectively oxygenate blood of hematocrit 35% at flow rates of at least 10 ml/minute and that higher flow rates may be used to oxygenate blood or perfusates of a lower hematocrit. The results were verified in three different practical experimental applications: isolated rat liver, rabbit heart, and rat free skin flap perfusion.

Animals↗
PubMed1982

Differential effect of tungsten on the development of endogenous and nitrate-induced nitrate reductase activities in soybean leaves.

The effect of tungsten on the development of endogenous and nitrate-induced NADH- and FMNH(2)-linked nitrate reductase activities in primary leaves of 10-day-old soybean (Glycine max [L.] Merr.) seedlings was studied. The seedlings were grown with or without exogenous nitrate. High levels of endogenous nitrate reductase activities developed in leaves of seedlings grown without nitrate. However, no endogenous nitrite reductase activity was detected in such seedlings. The FMNH(2)-linked nitrate reductase activity was about 40% of NADH-linked activity. Tungsten had little or no effect on the development of endogenous NADH- and FMNH(2)-linked nitrate reductase activities, respectively. By contrast, in nitrate-grown seedlings, tungsten only inhibited the nitrate-induced portion of NADH-linked nitrate reductase activity, whereas the FMNH(2)-linked activity was inhibited completely. Tungsten had no effect on the development of nitrate-induced nitrite reductase activity. The complete inhibition of FMNH(2)-linked nitrate reductase activity by tungsten in nitrate-grown plants was apparently an artifact caused by the reduction of nitrite by nitrite reductase in the assay system. The results suggest that in soybean leaves either the endogenous nitrate reductase does not require molybdenum or the molybdenum present in the seed is preferentially utilized by the enzyme complex as compared to nitrate-induced nitrate reductase.

Journal Article↗
PubMed1982

In Vivo Nitrate Reduction in Roots and Shoots of Barley (Hordeum vulgare L.) Seedlings in Light and Darkness.

In vivo NO(3) (-) reduction in roots and shoots of intact barley (Hordeum vulgare L. var Numar) seedlings was estimated in light and darkness. Seedlings were placed in darkness for 24 hours to make them carbohydrate-deficient. During darkness, the leaves lost 75% of their soluble carbohydrates, whereas the roots lost only 15%. Detached leaves from these plants reduced only 7% of the NO(3) (-) absorbed in darkness. By contrast, detached roots from the seedlings reduced the same proportion of absorbed NO(3) (-), as did roots from normal light-grown plants. The rate of NO(3) (-) reduction in the roots accounted for that found in the intact dark-treated carbohydrate-deficient seedlings. The rates of NO(3) (-) reduction in roots of intact plants were the same for approximately 12 hours, both in light and darkness, after which the NO(3) (-) reduction rate in roots of plants placed in darkness slowly declined. In the dark, approximately 40% of the NO(3) (-) reduction occurred in the roots, whereas in light only 20% of the total NO(3) (-) reduction occurred in roots. A lesser proportion was reduced in roots because the leaves reduced more nitrate in light than in darkness.

Journal Article↗
PubMed1982

Lead sulphide and traditional preparations: routes for ingestion, and solubility and reactions in gastric fluid.

Lead sulphide frequently occurs as a fallacious materia medica in traditional preparations used throughout the Moslem world. Although one of the least soluble lead compounds, use of this material as an eye powder has been directly associated with elevated blood-lead levels in children. Data are presented from animal studies which show the primary route for ingestion of the eye cosmetic is not transcorneal transport. Conversion of the sulphide to the more soluble (and hence more readily absorbed) chloride form is shown to occur in gastric fluid and, significantly, a marked dependence of the rate of dissolution on particle size is found. This may explain the disparity in previous reported values for the extent of absorption of ingested lead sulphide.

Animals↗