Biomedical subjects

I H Hall

Publications and source records attributed to I H Hall.

At least 55 records · Page 3Linked to original sources

PubMed1996

Anti-inflammatory activity of 2,3-dihydrophthalazine-1,4-diones in CF1 mice.

2,3-Dihydrophthalazine-1,4-diones were observed to be potent anti-inflammatory agents as well as capable of protecting against endotoxin shock in mice at 8 mg/kg i.p. These agents blocked both locally- and centrally-induced pain at 8 mg/kg i.p. In part they appear to mediate their effects due to their ability to suppress the release of cytokines such as TNF alpha and IL-1 from macrophages, as well as the binding of these cytokines to high-affinity receptors on target cells involved in the inflammation process. Lysosomal hydrolytic enzymes as well as 5'-lipoxygenase activities were reduced by the agents.

Analgesics↗

PubMed1995

Structure activity relationships of 4-substituted 1-acyl and 1,2-diacyl-1,2,4-triazolidine-3,5-diones as anti-inflammatory agents in rodents.

1-Acyl and 1,2-diacyl 1,2,4-triazolidine-3,5-diones proved to be potent anti-inflammatory agents in rodents at 8 or 20 mg/kg. They were effective against induced edema, pleurisy, and septic shock. Furthermore, these agents were potent in blocking the writhing reflex suggesting that they should be effective against local pain generated by inflammatory processes. These compounds were not lysosomal hydrolytic enzyme or proteolytic enzyme inhibitors in mouse liver, macrophages or human leukocytes. However, the agents were potent inhibitors of prostaglandin and leukotriene de novo synthesis and have potential in acting as free radical scavengers.

Animals↗

PubMed1995

Anti-inflammatory activity of amine-carboxyboranes in rodents.

Amine-carboxyboranes are potent anti-inflammatory agents reducing induced edema and pleural effusion at 8 mg/Kg, i.p. They protect against LPS (Salmonella) induced septic shock from 2-8 mg/Kg/day and are effective in blocking pain mediated both locally and centrally. The mode of action of these agents is by blocking release of cytokines from macrophages, thus reducing lysosomal hydrolytic and proteolytic enzyme activities of affected cells. The agents also reduce prostaglandin and leukotriene synthesis by blocking the activities of regulatory enzymes of the respective pathways.

Animals↗

PubMed1995

The disposition, tissue distribution, and cellular transport of N-[[(trimethylamino)boryl]carbonyl]-L-phenylalanine methyl ester in CF1 mice.

The disposition and tissue distribution of 14C-labeled N-[[(trimethylamino)boryl]carbonyl]-L-phenylalanine methyl esther (1) determined in CF1 mice following i.v., p.o., and i.p. administration. Compound 1 was found to undergo rapid and extensive metabolism, and the majority of the radioactivity was found in the skin and carcass regardless of the route of administration. Approximately 55% of the radioactivity was recovered in urine and feces after 78 h; however, excretion via these routes was not complete. Degradation of compound 1 occurred at the amide bond at low pH (0.8) but at the ester bond a physiological pH. This difference in degradation was reflected in elevation of the blood radioactivity levels after p.o. administration compared to i.p. and i.v. administration.

Administration, Oral↗

PubMed1995

The anti-osteoporotic activity of amine-carboxyboranes in rodents.

Amine-carboxyboranes have been shown to prevent osteoporosis and loss of bone mass in rodents. In vitro studies using CF1 mouse pup calvaria and rat UMR-106 osteosarcoma cells showed that amine-carboxyborane derivatives reduced significantly the loss of intracellular calcium into the growth medium from 10(-4) to 10(-8) M over 48 hours. Amine-carboxyborane derivatives were more effective than calcitonin or simple boron salts. Calcium incorporation into these cells and proline incorporation into collagen was accelerated in the presence of amine carboxyboranes. The amine-carboxyborane derivatives effectively inhibited lysosomal and proteolytic enzymes as well as activities of serine elastase, prostaglandin cyclooxygenase, and 5'-lipoxygenase in mouse macrophages, human PMNs, leukocytes and Be Sal cells. IC50 values were in the range of 10(-6) M. In lactating ovariectomized female rats after administered amine-carboxyboranes for 14 days at 8 mg/kg/day orally, the femur and humerus showed increased volume, weight, density and ash weight. Serum calcium levels were elevated significantly with minimum reductions on serum inorganic phosphate levels. Femur calcium levels were elevated after treatment with amine-carboxyborane derivatives, but not with etidronate. Humerus total lipids after 14 days were slightly elevated probably due to increased levels of triglycerides and phospholipids.

Animals↗

PubMed1995

The cytotoxicity of N-Pyridinyl and N-quinolinyl substituted derivatives of phthalimide and succinimide.

The N-pyridinyl and N-quinolinyl substituted derivatives of phthalimides and succinimides demonstrated cytotoxicity against the growth of a number of cultured cell lines. The substituted succinimides were more effective than the unsubstituted succinimide derivative in reducing cell growth. On the other hand, phthalimide demonstrated more potent cytotoxicity than its N-substituted derivatives. Three representative examples N-[2-pyridinyl-1-oxide) methyl] phthalimide 8, 1-[N-2-phthalimidoethyl]-3,4-dihydroiso-quinoline 12, and 1-[N-(2-(1,2,3,4-tetrahydro-2-quinolinyl)] ethylphthalimide 14 were shown to inhibit L1210 leukemia DNA synthesis whereas RNA synthesis was not inhibited at 25-100 uM. All three agents inhibited the activities of DNA polymerase alpha, PRPP-amido transferase, nucleoside kinases, and dihydrofolate reductase. The cellular pool levels of d[GTP], d[CTP], and d[TTP] were reduced after 60 minutes incubation at 100 uM. The DNA molecule itself was not a target of these agents.

Animals↗

PubMed1995

Investigation of 3,5-isoxazolidinediones as hypolipidemic agents in rodents.

A series of 2-benzoyl-4,4-dialkyl-3,5-isoxazolidinediones proved to have potent hypolipidemic activity, lowering both serum cholesterol and triglyceride levels at 10 or 20 mg/kg/day, IP and orally in rodents. 2-(3,4,5-Trimethoxybenzoyl)-4,4-diethyl-3,5-isoxazolidinedione+ ++ (4) afforded the best hypolipidemic activity lowering normolipidemic CF1 mouse serum cholesterol levels 49% and serum triglyceride levels 34% at 20 mg/kg/day, IP. Compound 4 was selected as a typical derivative of the chemical class for further detailed studies. Serum cholesterol levels in normolipidemic Sprague Dawley male rats were reduced 45% after 8 weeks at 10 and 20 mg/kg/day of compound, orally. Serum triglyceride levels were reduced 38-49% at 10 and 20 mg/kg/day, orally. In vitro liver enzyme activities studies in normolipidemic CF1 mice showed the compound inhibited mitochondrial citrate exchange, acetyl CoA synthetase, HMG CoA reductase, acyl CoA cholesterol acyl transferase, acetyl CoA carboxylase, sn-glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase and heparin-induced lipoprotein lipase activities with increases in the activities of cholesterol ester hydrolase and ATP-dependent citrate lyase. Similar enzyme activities were inhibited in vivo except HMG CoA reductase activity was not inhibited in rat liver or small intestinal mucosa after 8 weeks drug administration. Cholesterol levels were reduced in tissues after 8 weeks administration of compound 4 in normolipidemic rats. Bile cholesterol and triglyceride levels were elevated after two weeks administration to rats at 20 mg/kg/day. Serum lipoprotein levels in normolipidemic and hyperlipidemic rats showed the cholesterol levels in VLDL and LDL fractions after 4, 6 and 8 weeks at 10 and 20 mg/kg/day were reduced whereas HDL-cholesterol levels were significantly elevated. Studies demonstrated that 3H-cholesterol and 14C-palmitic acid incorporation into lipids of the lipoprotein fraction was reduced by the drug but 32P-incorporation was generally elevated. The agent demonstrated no observable toxicity in rats after 8 weeks administration, orally. The acute toxicity study in normolipidemic mice at 20, 40 and 100 mg/kg/day, IP, demonstrated no observable harmful effects of the drug.

Animals↗

PubMed1995

Cytotoxicity of imides-N-alkyl semicarbazones, thiosemicarbazones, acetylhydrazones and related derivatives.

The semicarbazones, thiosemicarbazones and acetyl-hydrazones of phthalimide, o-benzosulfimide, naphthalimide and diphenimide demonstrated potent cytotoxicity against murine and human leukemia cell growth and cultured cell growth from human solid tumors. The major site of inhibition in L1210 leukemia cells was DNA synthesis after 60 min incubated with the agents at 25, 50 and 100 microM. De novo synthesis of purines at the regulatory enzyme sites of PRPP amidotransferase and IMP dehydrogenase were the major targets of the agent. Thymidylate synthetase, dihydrofolate reductase and ribonucleoside reductase activities were inhibited by the agents in a manner which would contribute to the overall reduction of DNA synthesis and cell death. d(NTP) pools were significantly reduced and the evidence suggests that the agents interacted with DNA affording DNA strand scission which would interfere with both template utilization by the polymerases and also ultimately reduce nucleic acid synthesis.

Amidophosphoribosyltransferase↗

PubMed1995

Synthesis and cytotoxicity of amine-borane adducts of cyclohexylamines and toluidines.

A series of cyano- and carboxyborane adducts of cyclohexylamines and toluidines were shown to be cytotoxic towards suspended single cell tumors. The carboxyborane adducts of cyclohexylamine were more potent than the cyanoborane adducts of cyclohexylamine or any of the toluidine derivatives. A number of the compounds were active at 8 mg/kg/day i.p. in the Ehrlich ascites carcinoma screen in vivo. The mode of action study with N-methylcyclohexylaminecyanoborane 10 in L-1210 lymphoid leukemia cells showed that RNA synthesis was markedly reduced followed by DNA synthesis. Purine de novo synthesis was suppressed at PRPP-amido transferase, IMP dehydrogenase, and dihydrofolate reductase enzyme sites. The agent also interfered with DNA template activity causing reduction of DNA polymerase alpha, and RNA polymerase I, II and III activities. The d[NTP] pools were marginally reduced while DNA viscosity was reduced and DNA fragmentation occurred.

Animals↗

PubMed1994

Acute toxic and teratogenic effects of cyclic imides in rodents.

Four structurally different cyclic imides or related derivatives (o-(N-phthalimido)acetophenone (1), 2,3-dihydrophthalazine-1,4-dione (2), N-(4-methylphenyl)diphenamide (3), and 4,6-dihydro-5H-dibenz[c,e]azepine (4) were examined for acute toxicity in mice at multiple doses, for long term toxicity at a single dose in rats, and for deleterious effects on fertility and pup development in rodents. No deleterious effects were observed when mice were administered agents at 20, 50, and 100 mg/kg/day for seven days. All other measured characteristics and values were normal for the four compounds. The principle effect of the compounds was to reduce the percent pregnancies in treated mice compared to the controls. Compound 2 afforded the greatest reduction of pregnancy (54%) at 100 mg/kg/day. Compounds 3 and 4 caused a minor reduction in pregnancy (12-20%). The compounds did not appear to cause measureable teratogenic effects; pups of treated rodents thrived and survived as well as controls. There were no effects on murine male fertility when compounds were administered at 20, 50, and 100 mg/kg/day for six weeks.

Animals↗

PubMed1994

Hypolipidemic activity of 4-substituted 1,2-diacyl-1,2,4-triazolidine-3,5-diones in rodents.

A series of 4-substituted 1,2-diacyl-1,2,4-triazolidine-3,5-diones were synthesized and shown to be hypolipidemic in rodents; serum cholesterol and triglyceride levels were significantly reduced following intraperitoneal and oral dosing at 20 mg/kg/day. The hypolipidemic activity of the triazolidine-3,5-diones was improved when R1 was either a phenyl or a butyl group. Tissue lipid levels were reduced in the liver, aorta, and small intestine, while fecal lipids, e.g. cholesterol, were increased after 14 days. Very low density lipid cholesterol levels were reduced but high density lipid cholesterol levels were significantly increased. It appears that the mode of action of the 1,2-diacyl-1,2,4-triazolidine-3,5-diones is by the inhibition of the de novo rate limiting enzyme for lipid synthesis. Enzyme activities suppressed by the agents included ATP-dependent citrate lyase, HMG CoA reductase, acyl CoA cholesterol acyl transferase, acetyl CoA carboxylase, sn-glycerol-3-phosphate aryl transferase, phosphatidylate phosphohydrolase, and cholesterol-7 alpha-hydroxylase.

Animals↗

PubMed1994

Anti-inflammatory and anti-osteoporotic activities of base-boronated nucleosides and phosphate-boronated nucleotides in rodents.

The 2'-deoxyribonucleoside cyanoboranes were effective anti-inflammatory agents in rodents at 2-8 mg/kg; they blocked induced edema, septic shock, and pleurisy. Overall compounds 3',5'-O-(bis- (triisopropylsilyl)-2'-deoxyinosine (1), 3',5'-O-bis(triisopropylsilyl)-2'-deoxycytidine (10), N3-(cyanoboryl)-2'-deoxycytidine (11), N7-(cyanoboryl)-N2-isobutyryl- 3',5'-O-bis(triisopropylsilyl)-2'-deoxyguanosine (20), and N7-(cyanoboryl)-N2- isobutyryl-5'-O-(4,4'-dimethoxytrityl)-3'-O-(triisopropylsilyl)-2' -deoxyguanosine (22) were the most active when all the anti-inflammatory screens are considered. The agents also blocked both local and central pain caused by inflammation. These nucleosides blocked calcium resorption but were less effective compared to other amine carboxyboranes. The inflammation process appeared blocked by these compounds because of their effectiveness in reducing both hydrolytic lysosomal enzyme and proteolytic enzyme activities. The agents were also dual inhibitors of prostaglandin cyclooxygenase and 5'-lipoxygenase activities in leukocytes and macrophages. These agents at 10(-4) M demonstrated no specific organ toxicity to ileum mucosa cells grown in tissue culture.

Animals↗

PubMed1994

The cytotoxic activity of cyclic imido alkyl ethers, thioethers, sulfoxides, sulfones and related derivatives.

Cyclic imides such as N-substituted alkyl ethers, thioethers, sulfoxides, sulfones and related derivatives were potent agents against human single cell tumors and selected solid tumor growths, eg adenocarcinoma of the colon and glioma. These agents in the L1210 lymphoid leukemia tumor model preferentially inhibited DNA synthesis. The regulatory enzyme sites in the purine pathway were targets of the agents. Other sites of inhibition were DNA polymerase alpha and thymidylate synthetase activities. d(NTP) pool levels were also reduced by the agents over 60 min.

Animals↗

PubMed1994

The cytotoxicity of 3-imino-1-oxoisoindolines in murine and human tissue culture cells.

Certain types of hypolipidemic agents have been observed to also function as cytotoxic agents. Previously reported hypolipidemic agents, 3-imino-1-oxoisoindolines, were evaluated for their anti-neoplastic activity. Selected agents were effective at inhibiting L1210, Tmolt3, HeLa-S3, KB nasopharynx, lung, osteosarcoma and glioma growth. 2-Propyl-3-imino-1-oxoisoindoline, (4), a representative compound of the class of agents, inhibited DNA and RNA syntheses of L1210 cells. The major site of inhibition was the purine pathway at IMP dehydrogenase. Other enzyme sites which were affected by (4) marginally were t-RNA and r-RNA polymerases, dihydrofolate reductase, aspartate transcarboxylase, and nucleoside kinases. d(NTP) pools of L1210 cells were reduced after 60 min. Incubation with (4).

Animals↗

PubMed1994

Hypolipidemic, anti-obesity, anti-inflammatory, anti-osteoporotic, and anti-neoplastic properties of amine carboxyboranes.

The amine-carboxyborane derivatives were shown to be effective antineoplastic/cytotoxic agents with selective activity against single-cell and solid tumors derived from murine and human leukemias, lymphomas, sarcomas, and carcinomas. The agents inhibited DNA and RNA synthesis in preference to protein synthesis in L1210 lymphoid leukemia cells. Inosine-monophosphate dehydrogenase apparently is a target site of the compounds; similar effects on phosphoribosyl-pyrophosphate amido transferase, orotidine-monophosphate decarboxylase, and both nucleoside and nucleotide kinases were observed. Deoxyribonucleotide pool levels were reduced in the cells; DNA strand scission was observed with the agents. In rodents, the amine carboxyboranes were potent hypolipidemic agents, lowering both serum cholesterol and triglyceride concentrations, in addition to lowering cholesterol content of very low-density lipoprotein and low-density lipoprotein (LDL) and elevating high-density lipoprotein (HDL) cholesterol concentrations. De novo regulatory enzymes involved in lipid synthesis were also inhibited (e.g., hypocholesterolemic 3-hydroxy-3-methyl-Coenzyme A reductase, acyl-Coenzyme A cholesterol acyltransferase, and sn-glycerol-3-phosphate acyltransferase). Concurrently, the agents modulated LDL and HDL receptor binding, internalization, and degradation, so that less cholesterol was delivered to the plaques and more broken down from esters and conducted to the liver for biliary excretion. Tissue lipids in the aorta wall of the rat were reduced and fewer atherosclerotic morphologic lesions were present in quail aortas after treatment with the agents. Cholesterol resorption from the rat intestine was reduced in the presence of drug. Genetic hyperlipidemic mice demonstrated the same types of reduction after treatment with the agents. The agents would effectively lower lipids in tissue based on the inhibition of regulatory enzymes in pigs. These findings should help improve domestic meat supplies from fowl and pigs. The amine-carboxyboranes were effective anti-inflammatory agents against septic shock, induced edema, pleurisy, and chronic arthritis at 2.5 to 8 mg/kg. Lysosomal and proteolytic enzyme activities were also inhibited. More significantly, the agents were dual inhibitors of prostaglandin cyclooxygenase and 5'-lipoxygenase activities. These compounds also affected cytokine release and white cell migration. Subsequent studies showed that the amine-carboxyboranes were potent anti-osteoporotic agents reducing calcium resorption as well as increasing calcium and proline incorporation into mouse pup calvaria and rat UMR-106 collagen.

Animals↗

PubMed1993

Terephthalic acid in Sprague-Dawley rats as a hypolipidemic agent.

Terephthalic acid at 20 mg/kg/day in lowered serum cholesterol and triglyceride levels in rats. The cholesterol content was lowered in the lipoprotein fractions. The effects of the agents on de novo lipid synthesis showed that similar enzymes were affected in rat liver and small intestinal mucosa cells as when compared to in vitro tissue culture cells from rats and humans, e.g. reduction of acyl CoA cholesterol acyl transferase and elevation of neutral cholesterol ester hydrolase activities suggest that net cholesterol esters deposition in foam cells should be reduced and plaque growth should be slowed. The suppression of LDL receptor binding and degradation by the drug suggest that less apoB lipoproteins are taken up by peripheral tissues. The elevated HDL receptor binding and internalization in the liver suggest that the drug accelerates cholesterol return to the liver. Additional studies show that cholesterol and bile acid secretion in the bile is elevated. However, the bile acids secreted are not lithogenic. Acute toxicity studies show that the agent appears to be safe in rodents. Two observations of increased serum alkaline phosphatase levels and increased liver vacuolation suggest some alteration of hepatic cell morphology, which requires further investigation.

Animals↗

PubMed1993

The hypolipidemic effects of 2-furoic acid in Sprague-Dawley rats.

2-Furoic acid was shown to be effective in lowering both serum cholesterol and serum triglyceride levels significantly in rats with an elevation of HDL cholesterol level at 20 mg/kg/day orally. LDL receptor activity was reduced in hepatocytes, aorta foam cells, small intestinal epithelium cells and fibroblasts. HDL receptor activity was elevated in the rat hepatocytes and small intestinal cells. These activities were correlated with inhibition of acyl CoA cholesterol acyl transferase activity. Neutral cholesterol ester hydrolase activity was elevated in rat hepatocytes and human fibroblasts. Thus, 2-furoic acid appears to interfere directly with activity of intracellular enzymes rather than affecting high affinity-mediated lipoprotein membrane receptors. In vivo treatment with 2-furoic acid led to reduction in the liver and small intestine ATP dependent citrate lyase, acetyl CoA synthetase, acyl CoA cholesterol acyl transferase, sn-glycerol 3-phosphate acyl transferase, phosphatidylate phosphohydrolase and heparin induced lipoprotein lipase activities. 2-Furoic acid reduced biliary cholesterol levels but the agent increased bile salts which are lithogenic. Acute toxicity studies in mice suggest that the agent has some hepatic toxicity effects. The LD50 was relatively low at 250 mg/kg IP in mice.

Animals↗

PubMed1993

Hypolipidemic activity and toxicity of 3-methoxy-N,N'-diaminophthalamide in rodents.

3-Methoxy-N,N'-diaminophthalamide was observed to be a potent hypolipidemic agent in rodents. Serum cholesterol and triglyceride levels in rats were significantly reduced as were lipid contents of the liver, small intestine, and aorta wall. VLDL and LDL cholesterol levels were significantly reduced. Unfortunately, HDL cholesterol levels were also markedly reduced. Furthermore, acute toxicity studies showed that the compound caused marked increases in serum CP kinase activity with doses of 40 and 100 mg/kg/day in mice. This is not a property of the 2,3-dihydrophthalazine-1,4-dione, the resultant product of the N,N'-diaminophthalamides. Apparently, closing the ring results in a safer compound with elevations in HDL cholesterol levels, a desirable characteristic in effective hypolipidemic agents.

Animals↗