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Biomedical subjects

H Jones

Publications and source records attributed to H Jones.

At least 181 records · Page 10Linked to original sources
PubMed1985

1,2,4-Triazolo[4,3-a]quinoxaline-1,4-diones as antiallergic agents.

A series of new 1,4-dihydro-1,2,4-triazolo[4,3-]quinoxaline-1,4-diones has been prepared. These compounds were tested as inhibitors of antigen-induced release of histamine (AIR) in vitro from rat peritoneal mast cells (RMC) and as inhibitors of IgE-mediated rat passive cutaneous anaphylaxis (PCA). Most of this new class of antiallergic agents showed good activity in the RMC and PCA tests. The most potent compound, 2-acetyl-7-chloro-5-n-propyl-1,2,4-triazolo[4,3-a]quinoxaline-1,4-dione (1x), with an I50 value of 0.1 microM, is 30 times more potent than disodium cromoglycate (DSCG) in the RMC assay.

Animals↗
PubMed1985

A double-blind controlled trial of etretinate (Tigason) and ibuprofen in psoriatic arthritis.

Etretinate (Tigason) and ibuprofen have been compared in a double-blind controlled trial in psoriatic arthritis to see if we could confirm a specific action for this vitamin A derivative suggested from earlier uncontrolled studies. Eleven out of 20 patients completed 24 weeks of therapy with etretinate (up to 0.5 mg/kg/day) whereas only 1/20 patients completed 24 weeks of therapy with ibuprofen alone. Etretinate improved skin lesions, and this may have encouraged patients to persist with it. Improvement of statistical significance was seen for articular index in both groups. In addition significant improvement in ESR, haemoglobin, C-reactive protein, and histidine occurred in the etretinate group. The main side effects of etretinate (which may preclude its use at a higher dose in this condition) included cracked and dried lips and sore mouth.

Adolescent↗
PubMed1985

Videodensitometric ejection fractions from intravenous digital subtraction left ventriculograms: correlation with conventional direct contrast and radionuclide ventriculography.

Forty-three patients who had undergone direct-contrast ventriculography were submitted to intravenous digital subtraction ventriculography and first-pass radionuclide ventriculography to compare the left ventricular ejection fractions obtained by each method. Ejection fractions were calculated by the area-length method from the direct contrast ventriculograms, by both area-length and videodensitometric methods from the digital subtraction ventriculograms, and by count densitometry from the radionuclide ventriculograms. Satisfactory correlations were found between values obtained by the late mask resubtracted videodensitometric method and the radionuclide method (r = 0.85) and by the digital ventriculographic area length method and direct-contrast method (r = 0.88). Videodensitometric methods may be an alternative way to estimate left ventricular ejection fractions accurately without reliance on geometric assumptions about the shape of the left ventricular cavity.

Analog-Digital Conversion↗
PubMed1984

Stereochemical considerations and the antiinflammatory activity of 6-amino-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ols and related derivatives.

The antiinflammatory activity of a series of 6-amino-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ols and related derivatives was examined using the reverse passive Arthus reaction (RPAR). The antiinflammatory activity of these compounds was markedly influenced by the stereochemistry of the amino alcohol moiety. The threo diastereomer exhibited activity in the RPAR, while the erythro diastereomer was devoid of any significant antiinflammatory activity. The antiinflammatory activity of the amino alcohols was also significantly influenced by the position and nature of the aromatic substituent. Latentiation of the amino alcohol function resulted in analogues exhibiting antiinflammatory activity equivalent to their amino alcohol precursors. Masking the amino alcohol function as a more stable derivative led to analogues exhibiting an antiinflammatory profile unique to their structural class.

Animals↗
PubMed1984

Synthesis of 2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl) benzo heterocycles. A novel series of orally active antiallergic agents.

A series of new 2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl) benzo heterocycles has been prepared. These compounds were tested as inhibitors of antigen-induced release of histamine (AIR) in vitro from rat peritoneal mast cells (RMC) and as inhibitors of IgE-mediated rat passive cutaneous anaphylaxis in the rat (PCA). Most of this new class of antiallergic agents showed good activity in the RMC assay. The most potent compound, 3-chloro-2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl)benzo[b]thiophe ne (6t), with an I50 value of 0.2 microM, is 15 times more potent than disodium cromoglycate (DSCG) in the RMC assay. Many compounds were orally active in the PCA test, and several of these compounds showed higher potency when given in this way to that shown by DSCG when given intraperitoneally.

Animals↗
PubMed1984

Pyrido[3',2':4,5]thieno[3,2-d]-N-triazines: a new series of orally active antiallergic agents.

A new series of orally active mediator release inhibitors, pyrido[3',2':4,5]thieno[3,2-d]-N-triazines, was synthesized and evaluated for antiallergic activity. Several products showed high activity as inhibitors or wheal information in the rat passive cutaneous anaphylaxis screen and as inhibitors of histamine release from passively sensitized rat mast cells. Many compounds were orally active in the PCA test. The most potent compound, 7-phenylpyrido-[3',2':4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)- one (10) with an I50 value of 0.05 microM, was 60 times more potent than disodium cromoglycate (DSCG) in the RMC assay.

Administration, Oral↗
PubMed1984

Optimum cell numbers for mixed lymphocyte responses in hanging-drop microcultures.

The conditions required for optimum mixed lymphocyte culture (MLC) responses in hanging-drop (HD) microcultures in Terasaki trays have been investigated. Compared with conventional (200 microliter) MLC, HD-MLC required 5-10 times fewer cells, and 10% of the amount of culture medium and 3H-thymidine label. Peak uptake of label in HD-MLC was mutually responder-stimulator concentration dependent. Differences in response to related and unrelated lymphocytes indicate that HLA-D determinants are detected in HD-MLC.

Cell Count↗
PubMed1984

Comparative structure-activity relationships for dihydropyridines as inhibitors of [3H]-nitrendipine binding vs cyclic nucleotide phosphodiesterases.

A comparison of the structure-activity relationships [SAR] for a number of compounds containing a dihydropyridine ring were investigated in vitro for the inhibition of [3H]-nitrendipine binding to membranes from rat ventricular muscle vs the inhibition of cyclic nucleotide phosphodiesterases [cNUC-PDE]. Although there were some gross similarities in the 2 SARs for these compounds, there were sufficient differences to indicate that these are 2 distinctly different biochemical properties of these compounds. Some of these compounds were relatively potent inhibitors of both cNUC-PDE and (3H)-nitrendipine binding. However, some analogs were potent inhibitors of one of the activities but relatively ineffective against the other activity. These data suggest that these 2 different biochemical mechanisms of action (and possibly others) may jointly influence the overall pharmacological profile of these compounds and indicate at least one reason why some of these compounds have different profiles of activity in vivo.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Clinical manifestations of otological syphilis.

One patient with early otological syphilis and five patients with late otological syphilis are described including audiological and serological findings. In patients with late syphilis poorer than expected speech discrimination scores relative to the pure tone audiograms were noted. Profound hypo-activity of vestibular responses to caloric stimulation was present in the cases of late otological syphilis. Routine non-treponemal serological tests were not sensitive enough to establish the diagnosis. It is recommended that more sensitive treponemal serological tests such as the FTA-ABS should be employed.

Adult↗
PubMed1983

RHC 3288 [1-methyl-2(1,3,4-oxadiazol-2(3H)-one-5-yl) benzimidazole] and related compounds. Novel inhibitors of histamine release from rat mast cells and human basophils.

RHC 3288 [1-methyl-2(1,3,4-oxadiazol-2(3H)-one-5-yl) benzimidazole] and twenty-five related 5-substituted oxadiazolones have been investigated for their antiallergic activities in three in vitro models of anaphylaxis. Sixteen compounds were potent (I50 less than or equal to 50 microM) inhibitors of antigen-induced release of histamine (AIR) from rat mast cells (RMC), and seven compounds inhibited anti-IgE-induced release of histamine from human basophils (I50 less than or equal to 100 microM). The antiallergic activity profiles of RHC 3288 and three other compounds in these models have been compared with that of disodium cromoglycate (DSCG). As inhibitors of AIR from RMC, RHC 3288, 3334, 3354 and 3380 were 3 to 10 times more potent than DSCG. In the same model (AIR from RMC), activity profiles of all four RHC compounds were identical to that of DSCG in the following respects: loss of inhibitory activity with increasing preincubation time, tachyphylaxis and cross-tachyphylaxis to each other, and inability to inhibit histamine release stimulated by Ca2+ ionophore, dextran + phosphatidyl serine and compound 48/80. RHC 3288, 3334, 3354 and DSCG had no effect in the other two models, histamine release from guinea pig lung mediated predominantly by IgG1 class of antibodies and anti-IgE-induced histamine release from human basophils. We conclude that RHC 3288 is a potent inhibitor of mediator release with a mechanism of action similar to that of DSCG.

Animals↗
PubMed1983

Effects of solubilisation on some properties of the membrane-bound respiratory enzyme D-amino acid dehydrogenase of Escherichia coli.

Solubilisation, delipidation and partial purification of the membrane-bound enzyme D-amino acid dehydrogenase of Escherichia coli K12 produced significant changes in several of its properties. Solubilised enzyme showed a broader substrate specificity, increased affinity for at least three substrates, and a lower pH optimum with D-alanine as substrate. Solubilised enzyme was more heat-labile than native enzyme, particularly at 37 degrees C, and re-binding to envelope preparations restored protection against heat denaturation. Activity of delipidated enzyme could be increased by addition of pure phospholipids. Native enzyme showed biphasic Arrhenius kinetics associated with phase changes of membrane lipids.

Cell Membrane↗
PubMed1983

Solubilisation of D-amino acid dehydrogenase of Escherichia coli K12 and its re-binding to envelope preparations.

D-amino acid dehydrogenase was found to be solubilised from envelope preparations of Escherichia coli by treatment with detergents but not with aqueous buffer solutions. Triton X-100-solubilised dehydrogenase was found to rebind to envelope preparations from the wild strain (AB 259) and its D-amino acid dehydrogenase-less mutant (DAD 13), and activities higher than those of native envelopes could be obtained. Re-binding was stimulated by magnesium. D-alanine stimulated cytochrome reduction and oxygen uptake were reconstituted when the solubilised dehydrogenase rebound to AB 259 envelopes. Re-binding of solubilised dehydrogenase to DAD 13 envelopes was independent of the growth medium used for DAD 13.

D-Amino-Acid Oxidase↗
PubMed1983

Decline of follicular oocyte maturation inhibitor coincident with maturation and achievement of fertilizability of oocytes recovered at midcycle of gonadotropin-treated women.

To examine whether a decline in follicular oocyte maturation inhibitor (OMI) is associated with attainment of oocyte maturation and fertilizability, OMI was measured in follicular fluid (FF) of 39 follicles of 20 normal women given human menopausal gonadotrophin and human chorionic gonadotrophin to induce follicular growth and maturation. Oocytes were aspirated per laparoscope, the fluid was saved, and the egg was observed, incubated, and inseminated with the husband's sperm. Concepti that developed to the 4- to 8-cell stage were transferred to the uterus and the women were followed for pregnancy. OMI activity in each FF was measured by using cultured cumulus-enclosed porcine oocytes (30-40 oocytes per FF sample). Estrogen, progesterone, oocytes (30-40 oocytes per FF sample). Estrogen, progesterone, and delta 4-androstenedione were measured in FF by radioimmunoassay. The FF of 13 preovulatory follicles yielding oocytes that were mature and fertilizable had significantly less OMI activity (mean +/- SEM) (0.58 +/- 0.10 unit/ml) compared to follicles yielding immature oocytes (2.8 +/- 0.56 units/ml; n = 9), atretic oocytes (5.5 +/- 2.5 units/ml; n = 7), or preovulatory oocytes with fractured zonae (1.9 +/- 0.63 units/ml; n = 7). The estrogen concentration (mean +/- SEM) of preovulatory follicles yielding mature fertilizable eggs or mature eggs with fractured zonae was greater (396 +/- 34 ng/ml; n = 20) compared to follicles yielding immature or atretic eggs (203 +/- 59 ng/ml; n = 9 and 97 +/- 47 ng/ml; n = 7, respectively; P less than 0.05). Progesterone concentration (mean +/- SEM; ng/ml) of FF was generally elevated in all preovulatory follicles (635 +/- 53) compared to immature or atretic follicles (230 +/- 64 and 76 +/- 17, respectively; P less than 0.05). It may be concluded that in normal follicle maturation there is a decline in OMI in the follicle containing an oocyte that becomes mature and fertilizable. There is also an increase in estrogen, progesterone, and follicle size. It is also possible to have an abnormal follicle maturation when there is an increase in size as well as FF, estrogen, and progesterone, but withut a decline in OMI--a situation which can lead to production of a nonfertilizable oocyte.

Adult↗
PubMed1983

Effects of inhibiting hepatocarcinogenesis upon the early fine structural changes induced in rat hepatocytes by 3'-methyl-4-dimethylaminoazobenzene.

Young adult male Leeds strain rats were fed for up to 10 weeks on diets containing either 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) or 0.06% 3'-MeDAB together with 0.0067% 3-methylcholanthrene (MeCh), which is known to inhibit the induction of hepatocarcinogenesis by the azo dye. Controls received either MeCh alone or a normal diet. Animals were killed at 10 days, 4 weeks and 10 weeks and their liver tissues examined by electron microscopy. Although MeCh did not prevent the induction of some non-specific fine structural changes such as glycogen depletion and proliferation of the smooth endoplasmic reticulum (ER), it did prevent the early dislocation and dispersal of the rough ER that was elicited by 3'-MeDAB. This provides further evidence indicating the importance to liver tumorigenesis of this rough ER change, which appears to be induced by all classes of chemical hepatocarcinogens and which, in comparative studies with carcinogen/non-carcinogen pairs of related chemicals, also appears to be specific to carcinogens.

Animals↗
PubMed1983

An example of age-associated interference in memorizing.

The study compared young and old intellectually superior individuals (mean ages 22.8 and 68.8) on Brown-Peterson memory tasks. Each trial required recall of four words following 15 seconds of backward counting, with a final recognition test for words in a 4-trial block. Each person participated in a switch and nonswitch condition of a Wickens paradigm--unchanged category membership of quadruplets for nonswitch and trial 4 change for switch. Usual recall loss from trial 2 onwards and recovery on trial 4 after a switch was found in both age groups, but significantly lower recall was shown by the old on trial 3 and also on trial 4 in the nonswitch condition. Recognition by the young was almost perfect, but the old had lower scores for words presented on trials 3 and 4 (nonswitch). All memory interference in young adults could, therefore, be attributed to retrieval difficulty, but a residual proactive deficit occurs in old adults.

Adolescent↗