Primary productivity and trophic status of a Kashmir Himalayan Lake

The paper deals with general limnology, phytoplankton production and trophic status of a Himalayan lake of Kashmir. The primary production as measured by in situ ¹⁴C istope technique ranged from 36 to 906 mgC.m^–2 d^–1 with characteristic seasonal variation. The photosynthetic efficiency was from 0.02 to 0.48% during the same period. The yearly (1975–1976) production was estimated at 134 gC.m^–2 m^–2, which shows that the lake has not yet reached a high level of eutrophication. The waterbody has been classified as mesotrophic.Formed part of thesis for which Ph. D. was awarded to MAK by Kashmir University, India     

Application of ultrasound to selectively localize nanodroplets for targeted imaging and therapy

Lipid-coated perfluorocarbon nanodroplets are submicrometer-diameter liquid-filled droplets with proposed applications in molecularly targeted therapeutics and ultrasound (US) imaging. Ultrasonic molecular imaging is unique in that the optimal application of these agents depends not only on the surface chemistry, but also on the applied US field, which can increase receptor-ligand binding and membrane fusion. Theory and experiments are combined to demonstrate the displacement of perfluorocarbon nanoparticles in the direction of US propagation, where a traveling US wave with a peak pressure on the order of megapascals and frequency in the megahertz range produces a particle translational velocity that is proportional to acoustic intensity and increases with increasing center frequency. Within a vessel with a diameter on the order of hundreds of micrometers or larger, particle velocity on the order of hundreds of micrometers per second is produced and the dominant mechanism for droplet displacement is shown to be bulk fluid streaming. A model for radiation force displacement of particles is developed and demonstrates that effective particle displacement should be feasible in the microvasculature. In a flowing system, acoustic manipulation of targeted droplets increases droplet retention. Additionally, we demonstrate the feasibility of US-enhanced particle internalization and therapeutic delivery.     

Ultrastructural changes in testis of gobiid fish Glossogobius giuris (Ham) induced by fenthion

Pesticides are known to affect the testis in fishes and cause cytomorphological changes or gross physiological alterations due to changes in its histology, retard gonadotrophic secretions thereby causing regression of the gonads. Light and ultrastructural studies were made on control and fenthion treated testis, interstitial gland and sperms of G. giuris during spawning phase after exposing them to different sub-lethal concentrations (0.05, 0.25 and 0.5 ppm) fenthion for a short-term period (24, 48, 72 and 96 hr). The results indicated extensive cytotoxic damages in the testis including atrophy of testis, reduction in lipoidal material in the interstitial cell and degeneration of sperms. The alteration in histology of testis, interstitial cell and sperms progressively increased with the increase in the sub-lethal concentration of pesticides.     

Myasthenia gravis associated with penicillamine treatment for rheumatoid arthritis.

Four patients with rheumatoid arthritis (R.A.) developed myasthenia gravis after taking penicillamine. In one patient withdrawal of the drug was followed by spontaneous remission of the myasthenia, and in two the dose of anticholinesterase was subsequently reduced. In the fourth patient continuing penicillamine treatment was associated with increasingly severe myasthenic features, but on withdrawal of the drug these resolved. As myasthenia gravis rarely complicates R.A. its onset in these patients shortly after the start of penicillamine treatment suggested that penicillamine may have precipitated this condition.     

Targeting the dimerization interface for irreversible inhibition of HIV-1 protease

A novel strategy was used to irreversibly inhibit HIV-1 protease. The inhibitor was designed to form a disulfide bond with Cys95, present at the dimerization interface of HIV-1 protease. The inhibitor was shown to be active against HIV-1 protease with K(inact) = 3.7 microM and V(inact) = 0.012 min(-1).     

EVALUATION OF ANTIOXIDANT DEFENSE RESPONSES TO LEAD STRESS IN HAPALOSIPHON FONTINALIS‐3391

Lead (Pb) is a heavy metal and a potentially hazardous environmental pollutant. In this study, the potential of lead to induce oxidative stress in biological systems was assessed using the cyanobacterium Hapalosiphon fontinalis‐339 as model test organism. The impact of lead toxicity on the cellular antioxidant system and the biochemical modulations that result in generation of antioxidant defense responses were also studied. To determine the effect of Pb toxicity, the test organism was grown in the presence of various concentrations (0.05, 0.10, 0.20, 0.40, 0.80, 1.0, 1.20, and 1.25 mg · L^?1) of exogenous lead chloride (PbCl₂), and its effects on growth were observed in terms of the change in chl content. There was a significant increase in metal uptake by the alga with a concomitant decrease in growth. Lead stress appeared to significantly up‐regulate the levels of stress‐related antioxidant enzymes—such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)—while a decrease in catalase (CAT) levels was observed. In addition, the levels of nonenzymatic antioxidants, oxidized and total glutathione, were changed. Our results suggest the existence of a potent antioxidant defense machinery in H. fontinalis‐339 and this organism can be employed to monitor lead toxicity in the environment.     

Comparative limnology of nine lakes of Jammu and Kashmir Himalayas

Two lakes in the lower Siwalik Himalayas, five in the Kashmir valley and two situated in the high mountains of the Kashmir Himalayas were investigated for their physico-chemical and biological features. The lakes, differing significantly in their morphology and in thermal behaviour, rank from the subtropical monomictic to the dimictic type. The lakes at high altitudes (> 3000 m) have very low electric conductivity which increases with the decrease in altitude. The most dominant ions in water are calcium and bicarbonate. The macrophytic vegetation of the lakes does not show any definite relationship either with altitude or with physico-chemical milieu. In the lakes with low fertility the phytoplankton is dominated by diatoms and Chlorophyceae but in eutrophic lakes Cyanophyceae predominate. The zooplankton population of the lakes is mainly comprised of rotifera. On the basis of general limnological features and the rates of phytoplankton production most of the lakes may be categorized either as eutrophic or in the process of rapid evolution. Only one lake is oligotrophic.     

Piperine modulation of carcinogen induced oxidative stress in intestinal mucosa

The plasma-borne long-chain free fatty acids (FFA) enter skeletal muscle cells. Upon entering they are oxidized or esterified and a fraction remains free (non-esterified). The data on free fatty acids in skeletal muscles remain highly controversial. Furthermore, the composition of individual fatty acids in various lipid fractions including free fatty acids, monoglyceride and diglyceride in muscles has not been characterized. Also data on the composition of fatty acids esterified into muscle triglycerides and phospholipids are incomplete. The present study was undertaken to examine a composition of fatty acids in lipid fractions of different skeletal muscle types. For this purpose, samples of the rat soleus, red and white portions of gastrocnemius were excised, trimmed of visible fat and fascias and immediately frozen in liquid nitrogen. Samples were then pulverized and, lipids were extracted and fractionated by thin-layer chromatography. Individual long-chain fatty acids in different fractions were identified, characterized and quantitated by gas-liquid chromatography. FFA composition in the plasma was also determined. The total FFA content in the soleus, red and white gastrocnemius was 69.1 ± 10.8, 49.0 ± 13.6 and 22.7 ± 8.6 nmol/g, respectively. Palmitic and oleic acids were the major fatty acids in the muscles FFA fraction. Monoglyceride fraction of each muscle contained palmitic, stearic and linoleic acid as the major fatty acids, Diglyceride fraction contained mostly palmitic and oleic acid whereas triglyceride fraction mostly palmitic and linoleic acid.. The fraction of phospholipids was composed mostly of palmitic and linoleic acid but contained also considerable percentage of archidonic acid. Total plasma FFA/muscle FFA ratio depended on a muscle type and was: 2.4 in the soleus, 3.5 in the red and 7.4 in the white gastrocnemius. This assured transport of FFA to the myocytes. However, there were great differences in the ratio between particular FFA within the same muscle as well between the muscles. It indicates that individual FFA are either selectively transported from the plasma to the muscles or selectively used within the myocytes or both.