The effects of aflatoxin B1 on rat fetal lung lipids

The administration of aflatoxin B1 to rats on days 17 and 19 of pregnancy caused increased synthesis of the total lipids and the fatty acids, and decreased synthesis of the phosphatidyl choline in 21-day-old fetal lung. Aflatoxin B1 caused toxicity in the fetal lung as evidenced by the excessive accumulation of the lamellar bodies and the osmiophilic spheroids in the type II cells and the alveolar lumen, respectively. The rearrangement of the lamellar form to the continuous sheet-like tubular myelin form was reduced in the alveolar lumen of the treated lung.

Serological and biochemical investigations among five endogamous groups of Delhi, India

Phenotype and gene frequencies for four blood group systems (ABO, MN, Rh and P) and haptoglobin among five endogamous groups of Delhi, India, are reported. All the systems are polymorphic in all the population groups. The average heterozygosity per locus in high (in the range 48-52 per cent) for all the groups. The extent of genic variability among the groups in terms of net codon differences per locus has been studied; the heterogeneity within the groups is large as compared to the between-group heterogeneity. There is no definite clustering of the of the groups with respect to their biological rank.

Mechanism of T5-induced DNA polymerase. I. Replication of short primer templates

Bacteriophage T5-induced DNA polymerase shows an initial phase of rapid synthesis, followed by a slower steady rate for much longer periods, with short DNA primer-templates (400 to 600 nucleotides long), in vitro. On extrapolating the line of steady rate back to 0 min, an intercept is obtained on the ordinate. With large DNA primer-templates, such as denatured T5 DNA (average chain length approximately 50,000 bases), the rate of synthesis remains constant and is equal to the initial rate obtained with short primer-templates. The zero time intercept was proportional to the amount of enzyme used and independent of temperature. Polymer challenge experiments indicate that the initial phase of rapid synthesis can be attributed to the processive mode of synthesis by T5 DNA polymerase. After synthesizing a stretch of DNA processively for about 200 nucleotide residues, the enzyme apparently forms a "dead-end complex" with the primer-templates used and must dissociate from the primer-template in order to resume synthesis. The average size of the product made processively, during various phase of synthesis, remains invariant and is in good agreement with the size of the zero time intercept per enzyme molecule.

Mechanism of T5-induced DNA polymerase. II. Characterization of the dead-end complex

We have shown that bacteriophage T5-induced DNA polymerase replicates short primer-templates (400 to 600 nucleotides long) at a rapid rate initially, followed by a slower rate sustained for much longer periods (Das, S. K., and Fujimura, R. K. (1977) J. Biol. Chem. 252, 8700-8707). In order to explain the slower steady rate and the results of polymer-challenge experiments, we conjectured the presence of a "dead-end complex" formed by the enzyme with the primer-template at the end of the primer elongation process. In this communication we present evidence which indicates that the presumed complex shows a first order kinetics of decay with a half-life of 3.5 min at 37 degrees. Energies of activation for the steady phase of synthesis and the decay of the dead-end complex were both found to be about 23 kcal/mol. This indicates that the dissociation of the aforesaid complex might be the rate-limiting step during the steady phase of synthesis. Correlation between the salt-induced reduction in the half-life of the complex and the increase in the steady rate of synthesis is in agreement with the above mentioned possibility.

Lipolytic enzymes of Trichophyton rubrum

Trichophyton rubrum cells contain lipase, phospholipases A and B and acyl CoA lysolecithin acyl transferase activities. This dermatophyte excretes lipase and phospholipase A into the growth medium when cultivated in Sabouraud's broth. Extracellular lipase has optimum activity at pH 8.0 whereas the intracellular lipase is maximally active at pH 8.0 whereas the intracellular lipase is maximally active at pH 7.0. The optimum pH of phospholipase A and B activities which are localized in 15000 g sedimentable cell fragments are 7.0 and 6.0 respectively. Supernatant obtained after removal of 1,005,000 g sedimentable fragments from cell extract contains acyl CoA lysolecithin acyl transferase which requires ATP, CoA, Mg2+ and an unsaturated fatty acid for its activity.

Effect of undecanoic acid on germination of microconidia of wild and undecanoic acid resistance mutant of Trichophyton rubrum

Effects of undecanoic acid (UDA) on germination of microconidia and elongation of germ tubes in UDA sensitive (udas) wild type Trichophyton rubrum and UDA resistant (udar) mutant derived from it, were studied. UDA inhibited conidial germination of udas and udar strains at 30 microgram/ml and 120 microgram/ml respectively which were minimum inhibitory concentrations of UDA for these two strains. When spores from both udas and udar were germinated in presence of subinhibitory concentration of UDA, germ tube growth was short. The elongation of germ tubes of spores pregerminated in absence of UDA was also inhibited by dose of UDA not sufficient to inhitib germination.

Phospholipid turnover in Trichophyton rubrum

Phospholipid synthesis, interconversion and breakdown in T. rubrum were followed by radioactive tracer. Synthesis and catabolism of phosphatidyl ethanolamine and phosphatidyl serine are most rapid; phosphatidyl choline and phosphatidyl inositol are metabolised rather slowly. Catabolism of phosphatidyl ethanolamine and phosphatidyl serine are uniform and their conversions to phosphatidyl choline and phosphatidyl inositol are suspected.

Corrugation of the skull in Paget's disease of bone

Paget's disease of bone has been known for about 100 years and the usual deformities of bone, e.g. bowed tibia, large head, are well described in medical text books. However, there does not appear to have been a description of corrugation of the skull as a recognized deformity in Paget's disease. Three cases are now described to illustrate this deformity as an unusual but valuable sign in this disease.

Synthesis and antihypertensive activity of some imidazoindole derivatives

The synthesis of pyridino[1,2-a]imidazo[5,4-b]indole (1) and thiazolo[3,2-a-a]imidazo[5,4-b-a]indole (2) has been achieved by phosphite reduction of 3-nitroso-6-phenylimidazo[1,2-a]pyridine and 5-nitroso-6-phenylimidazo[2,1-bb]thiazole. Compound 1 has shown strong antihypertensive activity in spontaneously hypertensive rats while compound 2 showed similar bioactivity both in spontaneously hypertensive rats and in normotensive dogs. A tricyclic amino derivative, 3-amino-2-phenylimidazo[1,2-a]pyridine, which has structural resemblance to compound 1, showed no hypotensive activity.

Effects of dietary fats on the fatty acid composition of enamel and dentinal lipids of rabbit molars

The effect of dietary fats such as butter, lard, cottonseed oil, and hydrogenated cottonseed oil on the fatty acid composition of enamel and dentin lipids of rabbit molars was studied. The enamel and dentin of molars of all of the rabbits contained a variety of fatty acids, palmitic, stearic, oliec, linoleic, and eicosapentaenoic being the major ones. Enamal lipids were more unsaturated than dentinal lipids in all of the groups. A significant difference was noticed in the fatty acid composition of both the enamel and dentin between these four groups of rabbits. Linoleic acid content was highest in both the enamel and dentin lipids of rabbits fed cottonseed oil. There was no marked difference in the saturated-unsaturated fatty acid ratio in both the enamel and dentin among rabbits fed cottonseed oil, lard, and butter. It is concluded that tooth lipids are responsive to diets and are in direct equilibrium with dietary components.

In search of complications in carpal tunnel decompression

A series of 170 hands in 152 cases of carpal tunnel decompression presented from the Hand Unit of the Royal Victoria Infirmary, Newcastle-upon-Tyne. Special emphasis is laid on unsatisfactory results of the surgical procedure and their remedy.

Exonuclease associated with bacteriophage T5-Induced DNA polymerase

T-5-induced DNA polymerase has been shown to possess a 3' leads to 5'-exonucleolytic activity. The exonuclease acts on both native and denatured DNA, but the apparent rate of degradation of denatured DNA is about five times faster than that for native DNA. The enzyme appears to act only on 3'-OH ends and produces mainly 5'-dNMP's. Like polymerase activity, exonuclease activity shows a pH optimum around 8.6. Mg2+, dithiothreitol, and N-ethylmaleimide had identical effects on both the activities. Nicked DNA was almost totally protected from exonuclease action under synthetic conditions, i.e., in the presence of 4dNTP's. Denatured DNA was partly degraded in the early phase of incubation with 4dNTP's, presumably due to unhybridized tails at the 3'-OH primer ends. However, the exonuclease activity was operative in both cases under synthetic conditions, as evidenced by template-dependent conversion of [3H]dTTP to [3H]dTMP.

A rationale for the treatment of metastatic neuroblastoma

In developing a chemotherapeutic program for children with disseminated neuroblastoma, we established three human neuroblastoma lines in cell culture to study the effects of dibutyryl cyclic AMP, papaverine, 5-trifluoromethyl-2'-deoxyuridine, and cyclophosphamide on cell growth, biochemical behavior, and morphology. Based upon our studies, a clinical treatment program was designed. We have treated 15 patients with disseminated neuroblastoma and have established the optimum dose range and sequence of these drugs. Early results were promising; plans for continuation of clinical and experimental studies were discussed.

Surface and lamina propria lipids of bovine gingiva

In terms of both quality and quantity, the surface lipids are noticeably different from the lamina propria lipids. The surface lipids are mainly structural in nature (cholesterol, cholesterol esters, and phospholipids), whereas the lamina propria lipids are mostly of storage types (triglycerides). The surface lipids are also more unsaturated, whereas the lamina propria lipids are more saturated. Even though gingiva is histologically similar to skin, bovine gingival surface lipids are different from the bovine skin surface lipids. Further studies are needed to investigate the importance of surface lipids in regulating the various physiologic functions of gingiva.

The size of the human omentum and methods of lengthening it for transplantation

The size of the omentum is variable and can only be predicted within the standard deviations. However, the lower limits of its size have now been ascertained over a large series and it is clear that it could be lengthened sufficiently to reach the vault of skull, mid-leg or mid-forearm levels in all cases. Of course, to do so will decrease its width. An alternative to pedicle transfer is to use the whole omentum as a free transplant by vascular anastomosis.

Study on the composition of bovine gingival lipids

The lipids in bovine gingival tissue were characterized qualitatively and quantitatively. The total lipid content was 2.35% on wet weight. The total nonpolar lipids and total polar lipids were 70.69 and 29.31% of the total lipids, respectively. Cholesterol esters, free fatty acids, and triglycerides were the major nonpolar lipids. Polar lipids were predominantly phosphatidyl choline, phosphatidyl ethanolamine, and sphingomyelin. Traces of glycolipids, lysophosphatidyl choline, phosphatidyl inositol, phosphatidyl serine, and prostaglandins were present. Oleic, palmitic, and stearic acids were found to be the major fatty acids in all lipid classes. Cholesterol esters, total polar lipids, and free fatty acids were more unsaturated than glycerides. Linolenic and arachidonic acid contents were highest in cholesterol esters and total polar lipids.

Detection of prostaglandins in bovine gingival tissue

It has been characterized earlier that bovine gingival lipids contain a fairly high level of arachidonic acid, a potential precursor of prostaglandin biosynthesis. The purpose of the present study was to investigate whether prostaglandins are natural components of bovine gingival tissues. Qualitative analysis of the lipid extract by a combination of thin-layer chromatography on plain and silver nitrate-impregnated silical gel plates and ultraviolet absorption spectroscopy strongly indicate the presence of PGE1, PGE2, and PGF2. There was also an indication for the occurrence of other prostaglandins, such as PGB, PGE3, PGF1, and PGF3.