Search PubMed⌕ Search

Biomedical subjects

J J Kabara

Publications and source records attributed to J J Kabara.

At least 19 recordsLinked to original sources
PubMed1987

Effects of fatty acids on gap junctional communication: possible role in tumor promotion by dietary fat.

Dietary lipids, in particular unsaturated fat, promote the development of many experimental tumors. However, no mechanisms to fully explain these effects have been elucidated. Recent reports, which we summarize here, suggest a role for gap junction-mediated intercellular communication in the process of tumor promotion. We also review tumor-promoting effects of dietary fat on experimental, particularly mammary, carcinogenesis. Our main focus is to review recent data examining the inhibitory effects of unsaturated fatty acids on metabolic cooperation in Chinese hamster V79 cells. These data suggest that inhibition of junctional communication may be involved mechanistically in the promotion of tumors by high levels of dietary unsaturated fat. Finally, potential mechanisms by which unsaturated fatty acids inhibit metabolic cooperation are examined.

Animals↗
PubMed1985

Hypolipidemic activity of the surfactants aminimides, and their effects on lipid metabolism of rodents.

A series of short chain fatty acid derivatives of aminimides were shown to possess hypolipidemic activity in rats and mice. Most of the agents tested lowered both serum cholesterol and triglyceride levels by at least 30% in mice and were effective in hyperlipidemic induced mice. 1,1-Dimethyl-1-(2-hydroxypropyl)-amine mersitimide lowered serum cholesterol levels 41% and serum triglyceride levels 56% at 20 mg/kg/day I.P. after 16 days. The same agent was active orally when administered to rats with a 38% reduction in serum cholesterol and a 52% reduction in serum triglycerides after 14 days. The agents inhibited liver acetyl CoA synthetase, ATP dependent citrate lyase and phosphatidate phosphohydrolase activities in vitro and in vivo. Reduction of cholesterol, triglycerides, neutral lipids and phospholipid levels were noted in the livers of mice treated for 16 days. In rat studies, cholesterol, triglyceride and phospholipid levels were reduced in liver, small intestine and the feces after two weeks' dosing. The cholesterol content was reduced in the very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions but elevated in the high density lipoproteins (HDL). Triglyceride levels were lowered in the VLDL, and neutral lipid levels were reduced in the chylomicron and VLDL fractions.

ATP Citrate (pro-S)-Lyase↗
PubMed1985

Evaluation of a new germicidal hand creme.

A new germicidal hand creme (Wash & Heal, Med-Chem Labs, Okemos, MI) was evaluated for its ability to reduce bacterial levels on the hands. Colony counts of coagulase-negative staphylococci were significantly reduced immediately after use, with notable antimicrobial activity present for the next 90-120 minutes. The germicidal creme was more active against staphylococci than gram negative bacilli. The creme's germicidal activity occurred rapidly and was targeted against gram positive cocci found on the skin; whereas the bar soap's activity occurred more slowly and had a broader target. This creme could be used between hand washings to further reduce microbial flora of the hands.

Bacteria↗
PubMed1984

Contamination of bar soaps under "in-use" conditions.

Bar and liquid soaps from 26 public lavatories were investigated for microbial colonies. Of 84 samples obtained from bar soaps, 100% yielded positive cultures; liquid soaps were essentially negative (3/39). Where quantitative data were gathered, bar soaps were found to contain as few as 100-200 CFU/ml but ranged to a high of greater than 6000 CFU/ml. Although laboratory-challenged bar soaps showed a quick loss of microorganisms (less than 6 hours), "in-use" bars continued to contain high levels of organisms, even after more than 48 hours. Qualitatively, bar soaps were found to harbour 2 to 9 different genera of organisms per bar. The microbial population obtained from bar soap represented over 16 different genera. The discovery of so many and such different microorganisms on bar soaps indicates that this form of soap may be a potential reservoir for the spread of cross-infection in public institutions.

Bacteria↗
PubMed1982

Influence of dietary disaccharides on mouth microorganisms and experimental dental caries in rats.

Osborne-Mendel rats were inoculated with Streptococcus mutans at weaning, divided into 5 groups and fed cariogenic diets containing 56 per cent sugar either as sucrose, maltose, lactose or combinations of sucrose/maltose and sucrose/lactose. The number of Strep. mutans on molar teeth of rats fed the diet high in maltose was much lower than for any other group of rats (p less than 0.01). Although Strep. mutans levels were low for rats fed maltose, the incidence of carious lesions was similar to rats fed sucrose when the textures of the two sugars were similar. Although maltose does not support plaque formation, it is a fermentable carbohydrate which can provide, if microorganisms are present, an environment conducive to dental decay. The incidence of carious lesions was highest among rats fed lactose.

Animals↗
PubMed1981

Changes in lipid levels of three skeletal muscles following denervation.

Nonpolar and polar lipids extracted from denervated rat gastrocnemius, plantaris, and soleus muscles were measured 7-9 days after unilateral sciatic nerve transection. The contralateral muscle (CCON) was used to obtain control lipid levels. After denervation changes in lipid concentrations were found in all three muscles. These alterations in lipid levels were generally in same direction but not to the same extent. The change in total nonpolar lipids (NL) was an increase in soleus greater than gastrocnemius greater than plantaris concentration. This change in lipid concentration was more apparent than real since the wet weight of muscle was decreased after denervation. Since polar lipid (PL) concentrations were not increased under these conditions of muscle weight loss, an actual decrease of polar lipids after denervation may be inferred. In contrast to the other two muscles, a marked difference was noted for polar lipids of denervated gastrocnemius muscle. An unidentified spot near the origin was detected. This area is the location of a nerve sprouting factor(s). The compound(s) was not detectable for the other two muscles. When the gastrocnemius from an unoperated animal rather than a CCON muscle was used as a benchmark, slight increases were found for total nonpolar, polar, and plasmalogen fractions following denervation. The changes for individual lipid fractions were less definable, except for the significant increase for the unknown polar compound near the origin. This spot was noted in extracts from CCON and DEN muscles but not in untouched control muscle. The CCON gastrocnemius muscle is therefore a poor control for determining effects of denervation on lipid levels and perhaps other biochemical parameters as well.

Animals↗
PubMed1981

The effect of surfactants upon the activity and distribution of glucosyltransferase in Streptococcus mutans 6715.

A modified Somogyi-Nelson procedure was used to determine the amount of reducing sugar produced during the reaction of S. mutans 6715 glucosyltransferase (GTF) with sucrose. This technique is an indirect measure of GTF activity and was used to determine the effects of the surfactants glycerol monolaurin (GML) and sodium lauryl sulfate (SLS) upon crude extracellular GTF. GML at 5, 10, and 15 micrograms/ml reduced culture filtrate GTF enzyme activity to an average of 81% of the control value. SLS at the only concentration tested (15 micrograms/ml) also caused a reduction, resulting in a GTF activity level that was 82% of the control value. Secondly, S. mutans 6715 cultures were grown in a medium containing Tween 80, or SLS. The cell-free culture filtrate and the cell-pellet were assayed separately for GTF activity. GML in the medium produced a decrease in culture filtrate GTF activity and an increased cell-pellet activity. The total (whole culture) activity for culture broths was 89% to 90% of the control value when 5, 10, or 15 micrograms/ml GML were added. Tween 80 supplemented culture medium resulted in increased culture filtrate GTF, while levels measured in the cell-pellet were decreased. Overall, Tween 80 caused a large increase in whole culture GTF activity. Cell cultures containing SLS at 15 micrograms/ml resulted in no change in the GTF activity as compared to the control, nor was there any change in the percent of GTF in the culture filtrate versus the percent which was in the cell-pellet. Higher concentrations of SLS could not be tested due to the inhibitory effect on cellular growth.

Fatty Alcohols↗
PubMed1980

Cholinesterase in muscle of dystrophic hamsters (Bio-40.54).

Isozyme patterns of cholinesterase (ChE) from heart, tongue, and skeletal muscle of normal and dystrophic hamsters are presented. Two principal bands, bands 1 and 2, were evaluated. Band 1 migrates faster towards the anode than does band 2. While bands 1 and 2 stain for AChE and were found in control muscles, only band 2 was stained by a pseudocholinesterase (BuChE) and was decreased in samples from dystrophic hamsters. The decrease in BuChE was most pronounced in dystrophic heart muscle. The low level of BuChE measured for dystrophic animal tissue was similar to isozyme patterns found in embryonic tissue and in denervated muscle. BuChE obtained by acrylamide gel electrophoresis along with 16S AchE appears to be a useful biochemical marker of nerve-muscle interactions.

Animals↗
PubMed1977

Antimicrobial lipids: natural and synthetic fatty acids and monoglycerides.

Over 40 natural or synthetic lipophilic compounds were screened for antimicrobial activity. Gram (+) bacteria and yeasts but not Gram (-) bacteria were affected by these agents. Epimino and selena fatty acids are more active than their corresponding straight chain unsubstituted fatty acids. The position of selenium influenced the antimicrobial activity of the fatty acids. The presence and position of a double or triple bond, usually an important factor in long chain fatty acids (greater than C14) had little or no effect in C11 fatty acids. Optimum antimicrobial activity was found for fatty acids and their corresponding monoglycerides when the chain lenght was C12. The dilaurin derivative was not active.

Animals↗
PubMed1976

Structure-function activity of azasterols and nitrogen-containing steroids.

Thirty-nine nitrogen-containing steroids were tested against two gram-negative, five gram-positive, and two yeast organisms. Many of these steroids have been previously reported to inhibit various metabolic processes involving sterol metabolism. While low minimal inhibitory concentration (MIC) values were recorded for sterol producing yeast, growth of bacteria which contain no sterols was also inhibited. Structure-function studies provided no relationship between biological activity and hypocholesteremic effects of these azasteroids. A hypothesis put forward is that amino and azasteroids are effectors of membrane which, in the case of mitochondria, lead to changes in adenosine triphosphate levels and/or dehydrogenase activity. Their effects on sterol metabolism, therefore, may be of secondary consideration.

Androgens↗