Synthesis and biological evaluation of 5-deazaisofolic acid, 5-deaza-5,6,7,8-tetrahydroisofolic acid, and their N9-substituted analogues

Prompted by recent disclosures concerning the potent antitumor activities of 5-deaza-5,6,7,8-tetrahydrofolic acid and 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF), we have prepared 5-deazaisofolic acid (3a) and 5-deaza-5,6,7,8-tetrahydroisofolic acid (4a). Reductive condensation of 2,6-diamino-3,4-dihydro-4- oxopyrido[2,3-d]pyrimidine with di-tert-butyl N-(4-formylbenzoyl)-L-glutamate and subsequent deprotection with trifluoroacetic acid yielded 5-deazaisofolic acid in good yield. Catalytic hydrogenation of this analogue then gave 4a. The 9-CH3 and 9-CHO modifications of 3a and the 9-CH3 derivative of 4a were also synthesized. Each of the new analogues was evaluated with a variety of folate-requiring enzymes as well as MCF-7 cells in culture. Compound 4a had an IC50 of ca. 1 microM against MCF-7 cells and was nearly 100-fold less potent than DDATHF in this regard. The three oxidized isofolate analogues were all poor inhibitors of tumor cell growth.

Histologic changes in the mouse testis after treatment with gossypol tetra-acetic acid

The effect of oral administrations (20 or 40 mg/kg body weight/day, for 21 days) of gossypol tetraacetic acid on the testis of the Parkes strain mouse was investigated. Gossypol treatment did not affect the body weight or testicular weight, but caused a significant depression in the weight of the seminal vesicle. Histologically, the testes in mice treated with gossypol possessed regressed seminiferous tubules showing the exfoliation of germ cells, the occurrence of giant cells, a disorganization of the germinal epithelium, the degeneration of germinal elements, intraepithelial vacuolation and dislocation of the Sertoli cells into the luminal portion. However, the effect of gossypol was not uniform, and normal features were also observed in the majority of the tubules in the testes of the gossypol-treated mice. When quantitatively analysed, the frequency of regressed seminiferous tubules was significantly higher in the testes in the treated mice than the controls. The results suggest that the gossypol treatment induces non-uniform regressive changes in the seminiferous tubules in the mouse testis.

Effect of sub-chronic endosulfan exposures on plasma gonadotrophins, testosterone, testicular testosterone and enzymes of androgen biosynthesis in rat

Insecticide endosulfan significantly inhibited testicular androgen biosynthesis in adult rats, when fed (po) at 7.5 and 10 mg/kg body weight dose levels, consecutively for 15 and 30 days. No appreciable alterations were apparent in body weights, testicular wet weights, and cytosolic and microsomal protein contents of testis in treated rats. Profound decrease in the levels of plasma gonadotrophins (FSH and LH) along with plasma testosterone and testicular testosterone were observed at both the doses of endosulfan, particularly after the longer exposure of 30 days. Activities of steroidogenic enzymes studied (3 beta- and 17 beta-hydroxysteroid dehydrogenases) were considerably lowered on longer exposure of endosulfan. A significant decrease in the contents/activities of microsomal cytochrome P-450 and related mixed function oxidases (MFOs) in testis of treated rats was also observed, along with a marked inhibition in the activity of cytosolic conjugation enzyme, glutathione-S-transferase at both doses studied. These biochemical changes were reversed when the endosulfan treatment was withdrawn.

Anthelmintic profile of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate in experimental helminthiases

Biological evaluation of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate against Ancylostoma ceylanicum, Nippostrongylus brasiliensis, Syphacia obvelata, Hymenolepis nana, H. diminuta and Cysticercus fasciolaris in experimental animals is reported. The compound (mg/kg) causes 100% elimination of A. ceylanicum (25 x 1), N. brasiliensis (100 x 1), S. obvelata (50 x 1), H. nana (250 x 3) and C. fasciolaris (50 x 10). It was also effective against the developing larvae (L3, L4 and L5) of A. ceylanicum at a single oral dose of 100 mg/kg. Another study indicated that the compound elicits 100% response within 32 hr of drug administration. The drug is well tolerated and LD50 is greater than 4500 mg/kg.

Colonoscopic polypectomy. North Indian experience

Colonoscopic snare polypectomy was carried out in 70 patients (40 children, 30 adults). There was a male preponderance in both the groups with a combined male: female ratio of 4.4:1. The majority of patients (85%) were aged 20 years or below. All patients presented with intermittent bleeding per rectum, ranging from 2 months - 6 years (mean 1.2 +/- 1.1 years) in children and 1-14 years (1.9 +/- 2.3) in adults. The majority of patients polyps were located in the rectum (73%) or in the rectosigmoid region (21%). Polyps were significantly more common in the rectum (80% vs 63%; P less than 0.01) and less frequent in the rectosigmoid (15% vs 30%; p less than 0.01) in children as compared to adults. A single polyp was present in 49 (70%) patients; 17 (24%) had 2-10 polyps, while 4 patients (2 children, 2 adults) had more than ten polyps. Most patients (94%) had polyps of less than 2 cm size. Histologically, the most polyps (91.5%) were of the juvenile variety; 39 (97.5%) children and 25 (83%) adults had this variety of polyp. The remaining 5 (17%) adults and one (2.5%) child had adenomatous polyps. The difference in the polyp histology between the two age groups was statistically significant (p less than 0.05). Only one patient (1.4%) had excessive bleeding following polypectomy. The present study suggests two important differences in the nature of polyps as compared to the West: 1) our patients were much younger, and polyps were rare after 40 years; and (2) histologically, the commonest polyps were of the juvenile variety (91.5%) while adenomatous polyps were rare (8.5%).

Psycho-social study of cigarette smoking

The present study has been carried out to assess the smoking habit among medical students and its relationship to demographic, social and psychological characteristics. Prevalence of smoking was found to be 30.79% in 854 students who responded to the questionnaire adequately. Smoking habit was more common among student who were married hailed from rural areas and the intensity of smoking increased with advancement in the career in medical profession. A strong association was observed between the habit and family history of smoking. The psychological factors associated with smoking were worry about examination unhappiness without justified cause and failure in friendship.

Identification of tachistoscopically presented alphanumeric stimuli in schizophrenia

Schizophrenics, general medical patients and non-patient controls were compared for their ability to identify tachistoscopically presented alphanumeric stimuli at six exposure durations. Schizophrenics did not differ from general medical patients but both were inferior to controls - a difference that increased as the exposure duration decreased.

Paralinguistic characteristics of speech in schizophrenics and depressives

Schizophrenics, depressives, patients with anxiety neurosis and normal controls were asked to comment freely for 2 min on photographs depicting seven facial emotional expressions. Schizophrenics commented for the shortest duration of time with characteristic vocalization; depressives' speech was characterized by low initiative time latency, greater duration of utterance but fewer word-counts.

Oral clonidine: an effective growth hormone provocative test

Twenty normal statured healthy children (8 M; 12 F) aged 9-16 years were subjected to growth hormone (GH) provocative tests. The mean basal GH level was 2.0 +/- 0.42 ng/ml (+/- SEM). The mean peak levels of GH were 11.9 +/- 2.19 ng/ml (+/- SEM) after exercise, 9.82 +/- 2.81 ng/ml (+/- SEM) after insulin and 15.2 +/- 2.54 ng/ml (+/- SEM) after oral clonidine. A significant rise (peak level greater than 7 ng/ml) of serum GH was found in 70, 80 and 85% of children after exercise, insulin and oral clonidine tests, respectively. The observation in the present study indicates that oral clonidine test, a safer, easier and more economical test than insulin hypoglycemia, is equally potent and can be done in out patients.

Toxicity of endosulfan on kidney of male rats in relation to drug metabolizing enzymes and microsomal lipid peroxidation

Endosulfan administration (po, 15 and 30 days at 7.5 and 10 mg/kg body wt respectively) inhibited the activity of microsomal mixed function oxidases in kidney tissue of male rats. Microsomal and cytosolic protein contents of kidney were significantly increased following 30 days endosulfan exposures. Profound induction in the activity profiles of alcohol dehydrogenase and cytosolic glutathione s-transferase was noticed, however, no such change was apparent in the activity of aldehyde dehydrogenase. Microsomal preparations from treated animals showed a dose and duration dependent increase in spontaneous lipid peroxidation. The observed biochemical changes persisted even after 7 days normalcy allowance provided after the endosulfan (10 mg/kg body wt) withdrawl. The results suggest a substantial renal toxicity of endosulfan to male rats in relation to microsomal mixed function oxidases and associated functions which possibly resulted from lipid peroxidative damage of microsomal membrane in treated animals.

Differential effects of chronic endosulfan exposure to male rats in relation to hepatic drug metabolism and androgen biotransformation

Chronic endosulfan exposure in rats led to considerable increase in the activities of drug metabolizing enzymes, whereas it had inhibitory effect on the activities of enzymes involved in the androgen biotransformation. Endosulfan also produced a dose- and duration-dependent increase in microsomal lipid peroxidation. The alterations produced after shorter duration showed much variation with respect to the dose levels and exposure period of endosulfan studied. The above biochemical changes were reversed after endosulfan withdrawal.

Triton: stratospheric molecules and organic sediments

Hydrocarbons and nitriles are produced in Triton's stratosphere by energetic electrons from Neptune's magnetosphere and other charged particle sources. Laboratory plasma experiments reported here show a substantial yield of molecules from low pressure flows of 10(-3) CH4 in N2 appropriate to Triton if both CH4 and N2 are saturated at the surface. An active magnetosphere similar to that of Uranus would result in a flux approximately 0.3 erg cm-2 s-1 of 0.1-1 MeV electrons in Triton's stratosphere; molecular production rates are then 10(6)-10(8) cm-2 s-1 for NH3, C2H2, HCN, and NCCN; tens of hundreds of gm cm-2 of these compounds per 10(9) yr (and lesser quantities of at least eight other molecules experimentally detected) would freeze to fine-grained white condensates in the lower stratosphere and sediment to the surface. Along with dark/colored organic haze produced in the stratosphere and other heteropolymers produced at the surface, these condensates are subjects to redistribution by aeolian processes and may appear as lag deposits and/or sediment layers. A simple eddy diffusion model indicates abundances approximately 10(19) molec cm-2 for HCN and C2H2, and > 10(17) molec cm-2 for NCCN, CH3CCH, CH2CCH2, and CH3CN in the stratosphere; these and other organic molecules will be detectable by IRIS if the stratosphere is (as expected) heated through ultraviolet and visible light absorption by the haze.

Inhibition of mammalian folylpolyglutamate synthetase and human dihydrofolate reductase by 5,8-dideaza analogues of folic acid and aminopterin bearing a terminal L-ornithine

Six new 5,8-dideaza analogues of folic acid and aminopterin containing a terminal L-ornithine residue were prepared by using multistep synthetic sequences. Each was evaluated as an inhibitor of hog liver folylpolyglutamate synthetase and human dihydrofolate reductase. Structural modifications at positions 2, 4, 5, and 10 were included to help define structure-activity relationships for compounds of this type. The compound N alpha-(4-amino-4-deoxy-5-chloro-5,8-dideazapteroyl)-L-ornithine (3f) was identified as the most potent inhibitor of mammalian folylpolyglutamate synthetase reported thus far (Ki congruent to 2 nM). Its 4-oxy counterpart, N alpha-(5-chloro-5,8-dideazapteroyl)-L-ornithine, was only 5-fold less inhibitory than 3f toward folylpolyglutamate synthetase but was found to be a much weaker inhibitor of dihydrofolate reductase than 3f.

Purification and characterization of guanosine diphospho-D-mannose dehydrogenase. A key enzyme in the biosynthesis of alginate by Pseudomonas aeruginosa

Alginate-producing Pseudomonas aeruginosa are usually associated with the cystic fibrosis lung environment and contribute to the high mortality rates observed among these patients. The present paper describes the purification and enzymatic properties of guanosine diphospho-D-mannose dehydrogenase (EC 1.1.1.132), a key enzyme in alginate biosynthesis by mucoid P. aeruginosa. The enzyme was overproduced using a plasmid vector containing algD (the gene encoding this enzyme) under control of the tac promoter. It was purified from cell-free lysates by lowering the pH to 5.0, heating the extract to 57.5 degrees C for 10 min, and discarding the protein pellet. The enzyme was selectively precipitated from the supernatant fraction with 45% acetone, resuspended in a 100 mM triethanolamine acetate buffer, pH 7.6, and ultimately purified by Bio-Sil TSK-400 gel filtration chromatography. The subunit molecular weight (Mr 48,000) as well as the N-terminal amino acid sequence corresponded to those predicted from the DNA sequence of algD. The native protein migrated as a hexamer of 290,000 molecular weight upon Bio-Gel A-1.5m gel filtration chromatography. Kinetic analysis demonstrated an apparent Km of 14.9 microM for the substrate GDP-D-mannose and 185 microM for the cofactor NAD+. GDP-D-mannuronic acid was identified as the enzyme reaction product. Several compounds (including GMP, ATP, GDP-D-glucose, and maltose) were found to inhibit enzymatic activity. GMP, the most potent of these inhibitors, exhibited competitive inhibition with an apparent Ki of 22.7 microM. Enzyme activity was also sensitive to the sulfhydryl group modifying agents iodoacetamide and p-hydroxymercuribenzoate. The addition of excess dithiothreitol restored enzyme activity, suggesting a possible involvement of cysteine residues in enzymatic activity.

Molecular analysis and repair of a defective Ef alpha gene

The molecular basis for the defective expression of Ef alpha was determined by analysis of the 5' region of a full length Ef alpha gene. The gene was isolated from a genomic library prepared from the A.CA/SnDv mouse strain. DNA sequence analysis of the 5' portion of the Ef alpha gene, which encodes the 5' regulatory sequences and the signal peptide, revealed the presence of a stop codon in the exon encoding the signal peptide. The remainder of the sequences were highly related to sequences found in previously characterized, functional E alpha alleles. Previous studies indicate that the f allele is transcribed at rates comparable to the rates of functional alleles and that mRNA accumulates in the cytoplasm. Primer extension analysis demonstrated that Ef alpha transcripts initiate identically to the functional Ek alpha allele, mapping the defect in the Ef alpha gene 3' of the transcriptional initiation site. To determine whether the stop codon in the signal peptide was the only major defect in this gene, reciprocal chimeric genes were constructed in which the 5' regions, including the first exons, of the defective f allele and the functional k allele were exchanged. The hybrid genes were inserted into an SV40 promotor driven expression vector for cotransfection with an Ek beta gene. Surface I-E expression was demonstrated using I-E specific mAb in Cos-7 and L cell lines transfected with the hybrid gene consisting of the 5' region of the k allele and the 3' portion of the f allele. Therefore, the single stop codon present in the exon encoding the leader peptide of the Ef alpha gene appears to be the only defect preventing this gene from expressing a functional E alpha-chain.

Molecular analysis and repair of a defective Ef alpha gene

The molecular basis for the defective expression of Ef alpha was determined by analysis of the 5' region of a full length Ef alpha gene. The gene was isolated from a genomic library prepared from the A.CA/SnDv mouse strain. DNA sequence analysis of the 5' portion of the Ef alpha gene, which encodes the 5' regulatory sequences and the signal peptide, revealed the presence of a stop codon in the exon encoding the signal peptide. The remainder of the sequences were highly related to sequences found in previously characterized, functional E alpha alleles. Previous studies indicate that the f allele is transcribed at rates comparable to the rates of functional alleles and that mRNA accumulates in the cytoplasm. Primer extension analysis demonstrated that Ef alpha transcripts initiate identically to the functional Ek alpha allele, mapping the defect in the Ef alpha gene 3' of the transcriptional initiation site. To determine whether the stop codon in the signal peptide was the only major defect in this gene, reciprocal chimeric genes were constructed in which the 5' regions, including the first exons, of the defective f allele and the functional k allele were exchanged. The hybrid genes were inserted into an SV40 promotor driven expression vector for cotransfection with an Ek beta gene. Surface I-E expression was demonstrated using I-E specific mAb in Cos-7 and L cell lines transfected with the hybrid gene consisting of the 5' region of the k allele and the 3' portion of the f allele. Therefore, the single stop codon present in the exon encoding the leader peptide of the Ef alpha gene appears to be the only defect preventing this gene from expressing a functional E alpha-chain.

Induction of pulmonary and hepatic cytochrome P-450 species by coal fly ash inhalation in rats

The effect of fly ash inhalation on xenobiotic metabolizing enzymes and heme metabolism in lung and liver has been studied in rats. Fly ash inhalation induced pulmonary and hepatic cytochrome P-450 content, aryl hydrocarbon hydroxylase and glutathione S-transferase activity. Induction of cytochrome P-450 was accompanied by induction of delta-amino levulinic acid synthetase in lung and inhibition of heme oxygenase in both lung and liver. Fly ash inhalation induced those species of cytochrome P-450 which closely resembled cytochrome P-448 in spectral properties and electrophoretic mobility.

Case report : grave's disease presenting as paranoid schizophrenia

The case of a 37 year old male is described who initially presented as paranoid schizophrenia unresponsive to anti-psychotic drug treatment and subsequently developed features of Grave's disease. Treatment with carbimazole alone improved his psychiatric symptoms.

Smoking habits of the medical students

Smoking habits of the medical students, both undergraduates and postgraduates, were evaluated by self-administering a predesigned proforma. 854 (66.05%) of the 1293 students responded, of whom, 30.7% of them were smokers. The number of smokers and the intensity of smoking increased with the advancement of their career at college. There were more smokers amongst the married and those with a history of smoking in their family. There was no systematic correlation between the socio-economic or rural/urban background and the smoking habit.

Gonadal toxicity of short term chronic endosulfan exposure to male rats

Endosulfan was studied for its effect on rat testicular toxicity in relation to the enzymes of androgen biosynthesis, viz. 3 beta-hydroxysteroid dehydrogenase (EC 1.1.1.145, 3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (EC 1.1.1.64, 17 beta-HSD); cytosolic conjugation enzyme, glutathione-S-transferase (EC 2.5.1.18); and testicular as well as serum testosterone levels at the dose levels of 2.5, 5.0, 7.5 and 10 mg/kg body weight fed orally for 7 and 15 days. Organ and body weights of the treated animals did not change significantly, however, the testicular protein contents were found to be increased appreciably after 7 days treatments. The activity profile of cytosolic conjugation enzyme showed much remained low during 7 days treatment, however, the two steroidogenic enzymes showed much individual variations in response to endosulfan treatments. An overall varied response with respect to testosterone biosynthesis and its secretion to serum was observed suggesting nevertheless, a profound hormonal imbalance caused by this insecticide to male gonads on short term chronic exposures.