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Biomedical subjects

W R Turner

Publications and source records attributed to W R Turner.

At least 19 recordsLinked to original sources
PubMed1991

Synthesis and evaluation of a series of 3,5-disubstituted benzisoxazole-4,7-diones. Potent radiosensitizers in vitro.

A series of 3,5-disubstituted-2,1-benzisoxazole-4,7-diones was synthesized and evaluated as radiosensitizers both in vitro and in vivo. These compounds were designed as non-nitro electron-affinic agents in an effort to alleviate some of the toxicities seen with the 2-nitroimidazole radiosensitizers evaluated in the clinic. Several compounds in this series were potent radiosensitizers in vitro, with sensitizer enhancement ratios of 2.0-2.3 at concentrations less than 0.5 mM. Compounds with potent in vitro activity were also evaluated in vivo. However, none of these compounds showed radiosensitizing activity in vivo. The reduction potentials of these compounds were determined by cyclic voltammetry and compared to other electron-affinic radiosensitizers. In general, the reduction potentials of this series of compounds was slightly more positive than the 2-nitroimidazoles, but they fell within the range postulated as acceptable to yield in vivo activity. The results suggest that factors other than reduction potential may be responsible for the lack of in vivo radiosensitizing activity observed for this class of radiosensitizers.

Animals↗
PubMed1991

Effect of PD 128763, a new potent inhibitor of poly(ADP-ribose) polymerase, on X-ray-induced cellular recovery processes in Chinese hamster V79 cells.

The modifying effects of PD 128763 (3,4-dihydro-5-methyl-1(2H)-isoquinolinone), a potent inhibitor of poly(adenosine-diphosphate (ADP)-ribose) polymerase, on radiation-induced cell killing were examined in Chinese hamster V79 cells. This compound has an IC50 value against the purified enzyme approximately 50X lower than 3-aminobenzamide (3-AB), a widely used specific inhibitor of the enzyme. Exposure of exponentially growing cells to a noncytotoxic concentration (0.5 mM) of PD 128763 for 2 h immediately following X irradiation increased their radiation sensitivity, modifying both the shoulder and the slope of the survival curve. When recovery from sublethal damage and potentially lethal damage was examined in exponential and plateau-phase cells, respectively, postirradiation incubation with 0.5 mM PD 128763 was found not only to inhibit both these processes fully, but also to enhance further the level of radiation-induced cell killing. This is in contrast to the slight effect seen with the less potent inhibitor, 3-AB. The results presented suggest that the mechanism of radiosensitization by PD 128763 is related to the potent inhibition of poly(ADP-ribose) polymerase by this compound.

Animals↗
PubMed1991

Dihydroisoquinolinones: the design and synthesis of a new series of potent inhibitors of poly(ADP-ribose) polymerase.

A series of dihydroisoquinolinones, formally rigid analogs of 3-substituted benzamides, and a series of 2,3-disubstituted benzamides were synthesized and evaluated as inhibitors of poly(ADP-ribose) polymerase. The results indicated that the orientation of the amide with respect to the substituent on the aromatic ring was critical for optimum inhibitory activity. Selected compounds were also evaluated for their ability to modify the radiation response of mammalian cells to ionizing radiation. A number of the 5-substituted dihydroisoquinolinones, which were very potent inhibitors of the enzyme, were able to enhance the lethal effects of ionizing radiation in mammalian cells, as measured by changes in the survival curve parameters Do and/or Dq.

Animals↗
PubMed1989

Effect of prenatal ethanol administration on the urogenital system of mice.

The purpose of the present series of studies was to determine whether an obstruction in the urogenital system or vesicoureteral reflux (reflux, the retrograde passage of urine from the bladder into the kidney) existed in mice prenatally exposed to ethanol which might account for the high incidence of hydronephrosis and hydroureter observed. In order to examine these possibilities, indigo carmine was injected into the bladder of 19-day fetuses previously exposed to ethanol on Day 10 of gestation and the presence of hydronephrosis and/or reflux determined. As expected, we found a greatly increased incidence of hydronephrosis and hydroureter. In addition, there was a significant increase in reflux in the ethanol-treated mice. The incidence of reflux appeared to be related to the severity of the hydronephrosis observed, though cases of hydronephrosis without reflux and reflux without hydronephrosis were found. These data suggest both hypotheses may be salient and that a multiplicity of urogenital abnormalities are found following prenatal ethanol exposure.

Animals↗
PubMed1988

Benzothiopyranoindazoles, a new class of chromophore modified anthracenedione anticancer agents. Synthesis and activity against murine leukemias.

The synthesis of the benzothiopyranoindazoles, a new class of chromophore modified anthracenediones related to mitoxantrone, is described. In this structural class the quinone moiety, which is believed to be responsible for the cardiotoxicity of the anthracyclines, has been designed out. The synthesis of the benzothiopyranoindazoles was carried out by a multistep sequence from requisite 1-chloro-4-nitro-9H-thioxanthen-9-one precursors. Reaction with a monoalkylhydrazine gave a 5-nitrobenzothiopyranoindazole adduct, which was catalytically reduced to a corresponding C-5 anilino intermediate. Alkylation of 7 with a requisite X(CH2)nNR1R2 (X = Cl, Br; R1, R2 = H, alkyl, acyl; n = 2,3) provided target "two-armed" benzothiopyranoindazoles or A-ring methoxy and/or side chain acyl intermediates, which could be converted to 3 by appropriate deprotection methodologies. Alternatively, certain target compounds 3 were synthesized by reaction of 7 with appropriately functionalized glycine precursors under Schotten-Bauman or BOP chloride condensation conditions to provide C-5 acylamino intermediates, followed by Red-Al reduction and deprotection steps. Described also is the synthesis of selected benzothiopyranoindazole congeners with proximal acylamino side chains at C-5 and B-ring sulfone functionality at S-6. Potent activity was demonstrated against murine L1210 leukemia in vitro (IC50 = 10(-7)-10(-9) M) as well as against P388 leukemia in vivo over a wide range of structural variants. In general, activity against the P388 line was maximized by (a) a basic side chain at N-2 and a dibasic side chain at C-5 with primary or secondary distal amine substitution, (b) certain patterns of A-ring hydroxylation with 8-OH and 9-OH most favorable, and (c) sulfide oxidation state at S-6. Besides having curative activity against the P388 line, the more active compounds were curative against murine B-16 melanoma in vivo. On the basis of their exceptional broad-spectrum in vivo anticancer activity, selected compounds in this series have been chosen for development toward clinical trials.

Animals↗
PubMed1987

Use of a bleeding time determination in the evaluation of unexplained hematuria.

Although von Willebrand's disease is an unusual cause of gross hematuria in children, it is readily treatable with fresh frozen plasma or cryoprecipitate. We present 2 cases of recurrent, painless gross hematuria owing to this congenital factor VIII deficiency disorder. In each case the diagnosis was suggested first by the finding of a prolonged bleeding time. We suggest that the bleeding time determination be included as part of the screening hemostatic studies used in the evaluation of unexplained hematuria.

Bleeding Time↗
PubMed1987

Anthrapyrazole anticancer agents. Synthesis and structure-activity relationships against murine leukemias.

Chromophore modification of the anthracenediones related to mitoxantrone in an attempt to provide agents with diminished or no cardiotoxicity has resulted in a novel class of DNA binders, the anthrapyrazoles. Their synthesis was carried out by a two-stage condensation sequence starting from requisite 1,4- or 1,5-dichloro-9,10-anthracenedione precursors. Reaction with a monoalkylhydrazine gave a chloroanthrapyrazole intermediate whose subsequent condensation with primary or secondary alkylamines provided the target "two-armed" anthrapyrazoles. A-ring 7,10-dihydroxy anthrapyrazoles were derived from amine condensation with intermediate 5-chloro-7,10-dihydroxyanthrapyrazoles or, alternatively, from intermediate 5-chloro-7,10-bis(benzyloxy)anthrapyrazoles followed by hydrogenolysis of the benzyl protecting groups to provide the target compounds. Potent in vitro activity was demonstrated against murine L1210 leukemia in vitro (IC50 = 10(-7)-10(-8) M) as well as against P388 leukemia in vivo over a wide range of structural variants. In general, activity against the P388 line was maximized by basic side chains at N-2 and C-5, two to three carbon spacers between proximal and distal nitrogens of the side chain, and A-ring hydroxylation. Besides having curative activity against the P388 line, the more active compounds were curative against murine B-16 melanoma in vivo. On the basis of their exceptional in vivo anticancer activity, A-ring dihydroxy compounds 71 and 74 reported in this study have been selected for development toward clinical trials.

Animals↗
PubMed1986

Posterior urethral valves: an update and review.

Here, in a comprehensive review of an important pediatric problem, the authors discuss the embryology, the clinical and radiological features, the complications and the management of posterior urethral valves.

Adult↗
PubMed1986

Reflux.

Explore the source record for details and available documents.

Child↗
PubMed1985

Novel bis[1,6-dihydro-6,6-dimethyl-1,3,5-triazine-2,4-diamines] as antitrypanosomal agents.

A series of novel 1,1'-(4,1-phenylene)bis [1,6-dihydro-6,6-dimethyl-1,3,5-triazine-2,4-diamines] was prepared and evaluated for activity against Trypanosoma rhodesiense in mice. The importance of the bis structure and the nature of the spacer between the two phenyl rings for optimal activity have been revealed. The potent parenteral activity of several analogues within this series as well as preliminary indication of oral activity lends encouragement to further development of this structural class.

Animals↗
PubMed1977

Urologic manifestations of Henoch-Schönlein purpura.

Henoch-Schönlein purpura involves the kidneys in about 50 per cent of cases. In adults the classic signs are usually absent. Open renal biopsy is valuable from a prognostic standpoint since the severity of the renal lesion can be correlated with the future clinical course.

Adult↗
PubMed1977

Retrospective study of 95 patients with staghorn calculus disease.

Medical records were reviewed for 95 consecutive patients hospitalized with a diagnosis of staghorn calculus disease. Of those patients in whom a conservative, non-operative approach was taken 30 per cent ultimately died of renal failure and/or sepsis. It is concluded that surgical intervention is the treatment of choice for patients with staghorn calculus disease.

Female↗
PubMed1977

Benign lesions of the tunica albuginea.

Although most testicular masses are malignant we present 7 cases to demonstrate that benign lesions of the tunica albuginea do occur and that these may be a source of diagnostic confusion. Consideration should be given to the possibility of a benign lesion of the tunica albuginea when the lesion is small, discrete, painless and projecting above the surface of the tunica albuginea. All of our patients were referred to us with a tentative diagnosis of testicular malignancy. We do not wish to decrease the importance of vigilance concerning testicular masses but the cases presented herein demonstrate that all masses of the testis are not malignant.

Adult↗