Anticonvulsant activity and selective inhibition of NAD-dependent oxidations by 1,4-disubstituted piperazines

Several 1-(1-aryl-3-ethylthiocarbamido)-4-(arylaminothiocarbonyl)piperazines were synthesized, characterized by their sharp melting points and elemental analyses and evaluated for anticonvulsant activity. All disubstituted piperazines at a dose of 100 mg/kg i.p. provided 10-90% protection against pentylenetetrazol-induced convulsions in mice. These disubstituted piperazines selectively inhibited the in vitro oxidation of nicotinamide adenine dinucleotide (NAD)-dependent oxidation of pyruvate, alpha-ketoglutarate, beta-hydroxybutyrate and NADH by rat brain homogenates. The NAD-independent oxidation of succinate remained unaltered. The anticonvulsant activity possessed by disubstituted piperazines was unrelated with their ability to selectively inhibit respiratory activity of rat brain homogenates. Amongst 1-(substituted benzyl)-4-(substituted benzoyl)piperazines exhibiting central nervous system (1, 2) depressant activity it was found that 1-(2-chlorobenzyl)-4-(2-chlorobenzoyl)piperazine possessed maximum activity (2). The ability of piperazine carbamides (3) and piperazinothiocarbamides to possess anticonvulsant activity (4) prompted synthesis of 1-(1-aryl-3-ethylthiocarbamido)-4-(arylaminothiocarbonyl)piperazines and evaluation of their anticonvulsant activity. The effects of these disubstituted piperazines were also investigated on the in vitro respiratory activity of rat brain homogenates in an attempt to elucidate the biochemical mechanism of action for their anticonvulsant activity.

Anticonvulsant activity and inhibition of cellular respiratory activity by substituted imidazolocarbamides

Several 1-(1-aryl-2-mercaptoacetylimidazole)-3-alkylcarbamides were synthesized and characterized by their sharp melting points, elemental analyses, and IR spectra. These substituted imidazolocarbamides possessed anticonvulsant activity, which was reflected by the 20-80% protection observed with these compounds against pentylenetetrazol-induced convulsions in mice. These substituted imidazolocarbamides selectively inhibited the in vitro oxidation of nicotinamide adenine dinucleotide (NAD)-dependent oxidations of pyruvate, alpha-ketoglutarate, beta-hydroxybutyrate, and NADH by rat brain homogenates. However, NAD-independent oxidation of succinate was not affected. The anticonvulsant activity possessed by 1-(1-aryl-2-mercaptoacetylimidazole)-3-alkylcarbamides had no relationship to their ability to inhibit cellular respiratory activity.

CNS depressant activity of pyrimidylthiazolidones and their selective inhibition of NAD-dependent pyruvate oxidation

Several 1-aryl-3-(2-pyrimidyl)thiocarbamides and their corresponding cyclized 2-arylimino-3-(2-pyrimidyl)thiazolid-4-ones were synthesized and characterized by their sharp melting points and elemental analyses. These thiocarbamides and thiazolidones possessed anticonvulsant activity against pentylenetetrazol-induced convulsions and potentiated pentobarbital-induced hypnosis in mice. Most of these thiocarbamides and thiazolidones selectively inhibited nicotinamide adenine dinucleotide (NAD)-dependent oxidation of pyruvate, where the use of added NAD dether hand, remained unaltered. The anticonvulsant activity of thiocarbamides and thiazolidones was unrelated to their ability to inhibit the respiratory activity of rat brain homogenates during oxidation of sodium pyruvate. Cyclization of thiocarbamides to the corresponding thiazolidones in general enhanced their CNS depressant and enzyme inhibitory effectiveness.

The conjunctival impression cytology between the diagnosed cases of dry eye and normal individuals

Background: The dry eye or tear film dysfunction is a common ophthalmic syndrome. Objective: To compare the results of conjunctival impression cytology between dry eye patients and normal individuals.Subjects and methods: A case control study including consecutive cases of dry eye syndrome was carried out. Individuals without dry eye were taken as control. Impression of conjunctiva with cellulose acetate filter paper was taken from inferonasal bulbar conjunctiva and was stained with Periodic Acid- Schiff (PAS) and counter-stained with haematoxylin and eosin. Main outcome measure: goblet cell density. Results: There was a female preponderance in dry eye disease. Of 114 dry eye cases, 49.2% eyes showed decreased or absent goblet cell density. In 72 normal individuals 73.7% eyes showed normal goblet cell density and 26.3% of eyes showed decreased or absent goblet cells (p < 0.001). The tear break-up time (TBUT) test was significantly more likely to be less than 10 seconds in cases as compared to the controls ( OR = 19.36, 95% CI = 7.56 – 52.52). Similarly, the goblet cell density was likely to be significantly reduced in cases with dry eye syndrome (OR= 2.25, 95% CI = 1.26 – 4.02, p = 0.003). Conclusion: Goblet cell density significantly reduces in dry eye syndrome. The impression cytology is a useful test for the diagnosis of dry eye syndrome. Key words: impression cytology; conjunctiva; dry eyes; tear filmDOI: 10.3126/nepjoph.v3i1.4277Nepal J Ophthalmol 2011;3(5):39-44

Management of corneal vascularization

DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5284 Nepal J Ophthalmol 2011; 3(2): 218-219