Liposomal amphotericin-B in the control of experimental aspergillosis in mice: Part I--Relative therapeutic efficacy of free and liposomal amphotericin-B

An animal model system for aspergillosis in BALB/c mice has been developed to evaluate the therapeutic efficacy of liposomal Amphotericin-B (Amp-B) and commercial Amp-B (Fungizone). Amp-B was intercalated into liposomes composed of egg phosphatidylcholine, phosphatidylethanolamine and cholesterol in a molar ratio of 6:1:3. A single dose (0.5 mg/kg body wt) of Amp-B both alone as well as in liposomal preparation was injected (i.v.) into animals infected with Aspergillus fumigatus. An increase in survival rate of animals and decrease in fungal count in lung, the most affected organ, were observed with liposomal formulation. Inclusion of Amp-B into liposomes also reduced the toxicity of the drug. Tissue distribution analysis of Amp-B by HPLC showed an increase in concentration of the drug in lung for both free and liposomal Amp-B in infected animals as compared to normal. Use of liposomal Amp-B increased the concentration of the drug in the disease affected organs such as lung, spleen. A longer persistence of the drug in the infected organs was also observed. The results suggest that inclusion of Amp-B in liposomes decreases its toxicity and improves therapeutic efficacy which at least in part could be due to more deposition and longer persistence of the drug in infected tissues.

Design of liposomes to improve delivery of amphotericin-B in the treatment of aspergillosis

The efficacy and toxicity of free and liposome intercalated amphotericin-B (Amp-B) in controlling Aspergillosis, caused by Aspergillus fumigatus in BALB/c mice were studied. Liposomal Amp-B had higher LD50 (8.1 mg/kg) as compared to that of the free drug (1.2 mg/kg). An improvement in the therapeutic index of the drug was observed with liposomal formulation of the drug. We also focussed on the effect of lipid composition and surface sugar in modulating the therapeutic potency of Amp-B. The most effective liposomal preparation was composed of egg phosphatidylcholine (EPC): L-alpha-phosphatidylethanolamine, dipalmitoyl (DPPE): cholesterol (Chol) in the molar ratio of 6:1:3. Amp-B intercalated into mannose grafted liposomes (LD50 = 9.3 mg/kg) was more effective as compared to the other formulation tested.

One-step sample preparation technique for broad spectrum gas chromatographic/mass spectrometric determination of organic priority pollutants in water

A rapid and cost-effective sample preparation technique is described for the qualitative and quantitative determination of a broad spectrum of organic contaminants in water. The technique involves simultaneous-in-situ acetylation of phenols with acetic anhydride and one-step extraction of phenol acetates and basic and neutral organic compounds from water. The extract is concentrated and analyzed by gas chromatography/mass spectrometry. The recovery and precision data of selected base, neutral, and phenolic compounds are given. The advantages and disadvantages of the in-situ acetylation/extraction technique are discussed.

Obesity- and sex-related alterations in growth hormone messenger RNA levels

The secretion of growth hormone (GH) is abnormal in genetically obese Zucker rats. Measurements of pulsatile GH release and circulating GH levels in lean (Fa/?) and obese (fa/fa) rats have shown that both are reduced in the latter. We have studied pituitary GH gene expression in order to understand the role of GH synthesis in this abnormality. Obese animals have lower pituitary GH mRNA levels than lean controls. Within each genotype a sex difference was observed with the female animals having lower GH mRNA levels than the males. It is unlikely that the GH abnormality is due to a generalized pituitary defect because prolactin mRNA levels were the same in all four groups of rats.

Photo-oxidation of sulphanilamide to blue product

Aqueous solutions of sulphanilamide undergo photolysis to produce several compounds including the blue oxidation product. The kinetics of the reaction leading to blue product has been studied and the apparent first-order rate constants for the formation of blue product at pH 1-11 have been calculated. Effect of certain antioxidants on this reaction at pH 7.0 and rates of inhibition have been determined. Ascorbic acid has been found to completely inhibit the formation of blue product. A reaction pathway for the photo-oxidation of sulphanilamide to blue product has been suggested. The blue product has been shown (James, 1940) to possess much higher antibacterial activity than sulphanilamide.

A spectrophotometric procedure for measuring oxoglutarate and determining aminotransferase activities using nicotinamide adenine dinucleotide phosphate-linked glutamate dehydrogenase from algae

A new spectrophotometric procedure is described for determining glutamate-dependent activities of aspartate aminotransferase, alanine aminotransferase, and ornithine aminotransferase with NADPH-linked glutamate dehydrogenase (GDH) from nitrate-grown Stichococcus bacillaris. The algal NADPH-GDH is highly specific for oxoglutarate and can catalyze the reduction of this keto acid in the presence of high glutamate concentrations, and thus is suitable for the measurement of oxoglutarate produced in glutamate-dependent amino-transferase reactions. The alga produces large amounts of NADPH-GDH which can be adequately purified in a few simple steps. The purified enzyme can be stored at 4 degrees C for several weeks without any detectable loss of activity. The algal NADPH-GDH can also be used for the estimation of small amounts of oxoglutarate in aqueous extracts.

Sarcoidosis, cysticercosis and cryptococcosis: an unusual association

The association of sarcoidosis, cysticercosis, and cryptococcosis has not been reported before. We describe a 55-year old woman with this unusual association. The patient had a favorable outcome of cryptococcal meningitis.

Photo-oxidation of sulphanilamide to azo and azoxy compounds

The second-order kinetics for the photochemical formation of azobenzene-4, 4-disulphonamide has been studied at pH 1-11 and at pH 7.0 in the presence of five antioxidants. The rate constants are not affected by changes in pH in the region of 5-9 at which the molecule is predominantly in the unionised form. The rate of formation of azobenzene-4, 4'-disulphonamide is inhibited upto 80% by ascorbic acid. A scheme for the photo-oxidation of sulphanilamide to the azo and azoxy derivatives has been outlined.

Further studies of Mycoplasma gallisepticum serum plate agglutination antigen grown in medium with artificial liposomes substituting for serum

Frey's medium supplemented with artificial liposomes substituting for serum was evaluated for Mycoplasma gallisepticum (MG) serum plate agglutination (SPA) antigen. Antigens prepared in batch (static) culture were compared with antigens grown in a fermenter. All batch-grown MG liposome antigens were highly sensitive, specific, and resulted in a greater yield compared with fermenter-grown liposome antigens. Compared with antigens prepared in Frey's medium with 12% swine serum (regular FMS) or with commercial SPA antigens, liposome antigens had a higher degree of specificity; however, they were similar in sensitivity and antigen yield. The only growth parameter to affect the yield per liter of batch-grown liposome antigen was the concentration of liposomes in the growth medium. The reduced yield and sensitivity of antigens grown in a fermenter may have been due to autoclaving the medium instead of sterilizing by filtration. There was no obvious difference between patterns of serum-medium-grown, liposome-medium-grown, or commercial SPA antigens upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The Relationship between Inorganic Nitrogen Metabolism and Proline Accumulation in Osmoregulatory Responses of Two Euryhaline Microalgae

Chlorella autotrophica, a euryhaline marine alga, and Stichococcus bacillaris, a salt-tolerant soil alga, grow in the presence of methionine sulfoximine (MSX), an inhibitor of glutamine synthetase, by maintaining high levels of NADPH-glutamate dehydrogenase. Nitrate reductase showed no change in MSX-adapted cells. For both species, MSX-adapted cells retained their capacity to accumulate proline in response to salinity, and in S. bacillaris no major shift was observed in the presence of MSX toward the accumulation of sorbitol. Following transfer from 33 to 150% artificial seawater (ASW), both algae exhibited increases in organic solute levels without a lag. Within 6 h of this sudden increase in salinity, the levels of proline in C. autotrophica and of proline and sorbitol in S. bacillaris were similar to those found in steady state 150% ASW cultures. Following transfer from 33 to 150% ASW, S. bacillaris continued [(14)C] bicarbonate photoassimilation at a normal rate and maintained active enzymes of nitrogen assimilation. The incorporation of [(14)C]phenylalanine into proteins was inhibited for about 30 minutes in MSX-free cells and 90 minutes in MSX-adapted cells following transfer from 33 to 150% ASW; the recovery after these lag periods was almost complete.

Stability-indicating assay of sulphacetamide in thermally degraded solutions

A stability-indicating assay method for the determination of sulphacetamide in thermally degraded solutions is reported. The method is based on the difference in the absorption maxima of sulphacetamide and sulphanilamide at pH 4.0 and their simultaneous determination by a two component assay using the analytical wavelengths of 258 nm and 268 nm the reproducibility of the method lies within +/- 4%. It is rapid and specific for the assay of sulphacetamide in degraded opthalmic preparations.

Sensitivity and specificity of Mycoplasma gallisepticum agglutination antigens prepared from medium with artificial liposomes substituting for serum

Three batches of strain A5969 Mycoplasma gallisepticum (MG) serum-plate-agglutination (SPA) antigen grown in regular Frey's medium with 12% swine serum, three batches grown in Frey's medium containing artificial liposomes instead of serum, and one commercial SPA antigen were evaluated for sensitivity and specificity. Sensitivity was measured using chickens exposed to MG by intraocular and intranasal inoculation. Specificity was measured in uninoculated controls and in groups inoculated with the oil-emulsion vaccines Haemophilus paragallinarum, infectious bursal disease inactivated virus vaccine, or Staphylococcus aureus. Sera were tested 1 to 8 weeks postinoculation. All SPA antigens had a perfect sensitivity score, except one liposome-grown antigen batch (LC). The two other liposome-grown antigen batches (LA and LB) maintained significantly higher specificity by yielding significantly (P less than 0.01) fewer false positive (FP) agglutination reactions than did the other antigens. The three antigen batches produced in medium with serum had intermediate levels of FP agglutination reactions. When known MG-negative sera were tested, MG SPA antigens LC and commercial SPA antigen yielded significantly (P less than 0.01) higher numbers of FP agglutination reactions than the other SPA antigens.

EFFECT OF pH ON THE PHOTOSTABILITY OF SULPHACETAMIDE EYE-DROP SOLUTIONS

The photolysis of aqueous solutions of sulphacetamide and sulphanilamide has been studied at pH 3-11. The rate of phatolysis appears to be the highest around pH 5.0 and 3.0 for sulphacetamide and sulphanilamide respectively. The log k-pH profiles of both compounds in the buffered and unbuffered solutions are presented. Various buffer ions e.g. citrate and phosphate catalyase the photodegradation reactions. Sulphacetamide eye-drop solutions prepared at pH 7 to 9 have ideal stability and clinical efficacy.

Pesticide burden on some insects of economic importance in Lucknow (India)

Some insects of economic importance from Lucknow (India) have been investigated for their pesticide burden. Chlorinated pesticide residues of DDT, BHC and aldrin along with their metabolites and isomers have been detected in crop pollinating insects, honeybees (Apis indica) and butterflies (Danais chrysippus and Eurema sp.) and predators, dragonfly (Platythemis sp.) and wasps (Polistes herebreus). DDT and their metabolites were present in concentrations which varied from 231-796 ng g(-1), followed by BHC (10-60 ng g(-1)), and aldrin (0.26-6.68 ng g(-1)). This finding is likely to stimulate newer interest in the area of pesticide research and start meaningful investigation to find if bioaccumulated pesticides would have adverse impact on otherwise beneficial potentials of such insects in our ecosystems.