N-(2-Benzoylphenyl)-L-tyrosine PPARgamma agonists. 3. Structure-activity relationship and optimization of the N-aryl substituent

3-?4-[2-(Benzoxazol-2-ylmethylamino)ethoxy]phenyl?-(2S)-((2- benzoylph enyl)amino)propionic acid (1) and (2S)-((2-benzoylphenyl)amino)-3-?4-[2-(5-methyl-2-phenyloxazol-4-y l)e thoxy]phenyl?propionic acid (2) are peroxisome proliferator-activated receptor gamma (PPARgamma) agonists and have antidiabetic activity in rodent models of type 2 diabetes. As part of an effort to develop the SAR of the N-2-benzoylphenyl moiety of 1 and 2, a series of novel carboxylic acid analogues, 23-66, modified only in the N-2-benzoylphenyl moiety were synthesized from L-tyrosine and evaluated as PPARgamma agonists. In general, only modest changes in the N-2-benzoylphenyl moiety of 1 and 2 are tolerated. More specifically, the best changes involve bioisosteric replacement of one of the two phenyl rings of this moiety. Addition of substituents to this moiety generally produced compounds that are less active in the cell-based functional assays of PPARgamma activity although binding affinity to PPARgamma may be maintained. A particularly promising set of analogues is the anthranilic acid esters 63-66 in which the phenyl ring in the 2-benzoyl group of 1 and 2 has been replaced by an alkoxy group. In particular, (S)-2-(1-carboxy-2-?4-[2-(5-methyl-2-phenyloxazol-4-yl)ethoxy]phen yl? ethylamino)benzoic acid methyl ester (63) has a pKi of 8.43 in the binding assay using human PPARgamma ligand binding domain and a pEC50 of 9.21 in the in vitro murine lipogenesis functional assay of PPARgamma activity. Finally, 63 was found to normalize glycemia when dosed at 3 mg/kg bid po in the Zucker diabetic fatty rat model of type 2 diabetes.     

Effects of time compression and time compression plus reverberation on the intelligibility of Northwestern University Auditory Test No. 6

The Tonal and Speech Materials for Auditory Perceptual Assessment, Disc 1.0 audio compact disc developed in 1992 includes several sets of degraded speech materials, two of which, time compression and reverberation, are described in this paper. The digital techniques used to compress the NU No. 6 materials (female speaker) on an 80386-based computer are described, along with a series of experiments on subjects with normal hearing that document the effects of the time compression on recognition performance. Experiment I examined at 70 dB SPL the effect on word recognition of 45, 55, 65, 70, and 75 percent compressions. Experiment II developed psychometric functions for the 45, 65, and 75 percent time-compression conditions. Experiment III defined the effects that time-compression degradation (45% and 65%) plus reverberation degradation (0.3 sec) had on the recognition performance on the NU No. 6 materials. Based on the experiments, four conditions (45% compression, 65% compression, 45% compression plus 0.3-sec reverberation, and 65% compression plus 0.3-sec reverberation) were selected and recorded on the compact disc. In the compact disc trials, normative data on the four conditions were developed from 120 listeners with normal hearing.     

Treatment of intermediate risk rhabdomyosarcoma and undifferentiated sarcoma with alternating cycles of vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide

Over 50% of patients with newly diagnosed rhabdomyosarcoma (RMS) are in the 'intermediate risk' group with a 3-year progression-free survival of approximately 65%. This group consists of stage 1, group III, non-orbit tumours; stage 2, group II and III; and all stage 3 patients utilising the Intergroup Rhabdomyosarcoma Study (IRS) staging system. The role of doxorubicin in the treatment of RMS has been controversial. Ifosfamide, both alone and in combination with etoposide, has significant activity in patients with RMS. The aim of this pilot study was to examine the efficacy and toxicity of a chemotherapy regimen of alternating cycles of vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide for intermediate risk RMS. 30 patients with intermediate risk RMS or undifferentiated sarcoma (US) were treated with alternating cycles of vincristine/doxorubicin/cyclophosphamide (VDC) and etoposide/ifosfamide (EI) at planned intervals of 3 weeks. Local treatment of the tumour in most cases was performed after four cycles of chemotherapy, followed by an additional 10 cycles of chemotherapy. At a median follow-up of 37.5 months, the Kaplan-Meier estimate of 3-year event-free survival was 85% (95% confidence interval 72-99%). The overall survival at 3 years was 91% (95% confidence interval 80-100%). No patient died from toxicity. The most common toxicity was febrile neutropenia in 35% of VDC and 26% of EI cycles. No nephrotoxicity or cardiac toxicity was seen. No patient progressed prior to week 12 local therapy. Alternating cycles of VDC and EI are an effective treatment for patients with intermediate risk RMS and US. Toxicity is tolerable. Delaying local treatment until week 12 does not compromise outcome.     

Comparative clinical study of cefonicid, chloramphenicol, and penicillin in community-acquired pneumonia

Telomere length in human somatic cells gradually decreases with the number of cell divisions and is regarded as a marker of somatic cell turnover. Mucosal cells of the affected colon show rapid turnover in individuals with active ulcerative colitis (UC). Telomere length was determined by Southern blot analysis of terminal restriction fragments (TRFs) from the colonic mucosa of 17 patients with UC in remission, two of whom showed dysplasia, and 17 control subjects without colitis. For each individual, mean TRF length was compared between rectal mucosa and unaffected cecal mucosa. The mean TRF length of the rectal mucosa was significantly less than that of cecal mucosa in UC patients (7.87 +/- 0.36kb versus 8.77 +/- 0.21 kb; P = 0.0015, Wilcoxon signed rank test), whereas no significant difference was detected in the control subjects. The extent of telomere shortening was 10.6 +/- 3.35% in UC patients, compared with 0.8 +/- 0.64% in noncolitis controls (P = 0.0024, Mann-Whitney U-test). Four UC patients, two of whom had dysplasia, showed telomere shortening of more than 20% in the rectal mucosa. These observations suggest that telomere shortening in the colonic mucosa of individuals with UC may represent the history of mucosal inflammation during disease of long duration, and that it may contribute to aneuploidy in UC.     

Immunodominance does not result from peptide competition for MHC class II presentation

Despite the fact that Ca2+ transport into the sarcoplasmic reticulum (SR) of muscle cells is electrogenic, a potential difference is not maintained across the SR membrane. To achieve electroneutrality, compensatory charge movement must occur during Ca2+ uptake. To examine the role of Cl- in this charge movement in smooth muscle cells, Ca2+ transport into the SR of saponin-permeabilized smooth muscle cells was measured in the presence of various Cl- channel blockers or when I-, Br-, or SO42- was substituted for Cl-. Calcium uptake was inhibited in a dose-dependent manner by 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and by indanyloxyacetic acid 94 (R(+)-IAA-94), but not by niflumic acid or 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS). Smooth muscle SR Ca2+ uptake was also partially inhibited by the substitution of SO42- for Cl-, but not when Cl- was replaced by I- or Br-. Neither NPPB nor R(+)-IAA-94 inhibited Ca2+ uptake into cardiac muscle SR vesicles at concentrations that maximally inhibited uptake in smooth muscle cells. These results indicate that Cl- movement is important for charge compensation in smooth muscle cells and that the Cl- channel or channels involved are different in smooth and cardiac muscle cells.     

Penetrating trauma of the internal carotid artery

OBJECTIVE: To assess management of penetrating internal carotid artery (ICA) injuries. DESIGN: Retrospective review of institutional protocol. SETTING: Level 1 trauma center in a major urban area. PATIENTS: Sixty-one patients with penetrating ICA injuries. INTERVENTIONS: In the period 1975 to 1987 (group 1; n = 36), management was based on individual surgeons' preferences. Between 1988 and 1995 (group 2; n = 25), an algorithm was employed: (1) hemodynamically stable patients with suspected ICA injuries underwent a diagnostic angiography; (2) surgically accessible injuries were reconstructed regardless of neurologic status with 2 exceptions: (a) neurologically intact patients with ICA occlusion were treated by anticoagulation and mild pharmacological hypertension and (b) minimal nonocclusive injuries were managed nonoperatively and followed up by serial angiography or duplex ultrasonography; and (3) heparinization, shunting, and completion angiography were employed. MAIN OUTCOME MEASURES: Neurologic status at admission and discharge were compared by the Fisher exact test. RESULTS: In group 1, 24 patients (67%) presented neurologically intact, and 12 (33%) with a deficit. Sixteen injuries were managed nonoperatively, 14 were repaired, and 6 were ligated. At discharge 6 (17%) were improved, 24 (66%) were unchanged, 6 (17%) were worse. Four patients (11%) died of cerebrovascular causes. In group 2, 19 patients (76%) presented neurologically intact, and 6 (24%) with a deficit. Eleven injuries were managed nonoperatively, 12 were repaired, and 2 were ligated. A death occurred in a patient who arrested, was admitted to the hospital in a coma, and died before ICA repair. CONCLUSIONS: Neurologic outcome after ICA injury is enhanced by an algorithm predicated on the liberal use of angiography, a predefined surgical approach, and selective observation.     

3H]-SR 27897B: a selective probe for autoradiographic labelling of CCK-A receptors in the brain

The binding and distribution of radiolabelled SR27897B, a potent CCK-A antagonist, was characterized using in vitro receptor autoradiography. Rapid imaging and quantitative analysis of [3H]SR27897B binding was obtained in a very short period of time (5 days) with a highly sensitive radioimager ensuring very short exposure times for isotopes such as tritium. Tritiated SR27897B binding sites are localized almost exclusively in the area postrema and the medical part of the nucleus tractus solitarius and in this nucleus the rostral-caudal distribution of CCK-A sites differed from that of sulphated CCK8 receptors. Receptor binding properties analyzed on 15 microns serial coronal sections showed on site receptor occupancy in these two regions with high affinity and selectivity characteristic of the CCK-A receptor. These results precisely locate the SR27897B binding sites and provide further support for the absence of heterogeneity of the CCK-A receptors in the rat brain.     

Toxicity of fotemustine in rat hepatocytes and mechanism-based protection against it

Fotemustine is a relatively novel DNA-alkylating 2-chloroethyl-substituted N-nitrosourea (CENU) drug, clinically used for the treatment of disseminated malignant melanoma in different visceral and non-visceral tissues. Thrombocytopenia has been observed in patients treated with fotemustine and liver and renal toxicities as well. In this study, firstly the metabolism of fotemustine was investigated in vitro and secondly the undesired cytotoxicity of fotemustine as well as different ways of protection against it. In rat hepatocytes, chosen as a model system, fotemustine was shown to cause lactate dehydrogenase (LDH) leakage, glutathione (GSH) depletion, GSSG-formation and lipid peroxidation (LPO). A reactive metabolite, DEP-isocyanate, is most likely responsible for these undesired cytotoxic effects. Based on the observed cytotoxicity mechanisms, chemoprotection with several sulfhydryl-containing nucleophiles and antioxidants was investigated. The sulfhydryl nucleophiles; GSH, N-acetyl-L-cysteine (NAC) and glutathione isopropylester (GSH-IP) protected almost completely against fotemustine-induced LDH-leakage and LPO. NAC and GSH protected partly against fotemustine-induced GSH-depletion. The antioxidant, vitamin E protected completely against fotemustine-induced LPO, but only partly against fotemustine-induced LDH-leakage and not against GSH-depletion. Ebselen, a peroxidase-mimetic organoselenium compound, did not show protective effects against the cytotoxicity of fotemustine, possibly because GSH is required for the bioactivation of ebselen. It is concluded that co-administration of sulfhydryl nucleophiles, in particular NAC and GSH-IP, possibly in combination with antioxidants, such as vitamin E, are effective against the toxicity of fotemustine in vitro. It might, therefore, be worthwhile to investigate the cytoprotective potency of these agents against undesired toxicities of fotemustine in vivo as well.