Dual targeting of the cancer antioxidant network with 1,4-naphthoquinone fused Gold(i) N-heterocyclic carbene complexes.

To achieve a systems-based approach to targeting the antioxidant pathway, 1,4-naphthoquinone annulated N-heterocyclic carbene (NHC) [bis(1,3-dimesityl-4,5-naphthoquino-imidazol-2-ylidene)-gold(i)] [silver(i) dichloride] (1), [bis(1,3-dimesityl-4,5-naphthoquino-imidazol-2-ylidene)-gold(i)] chloride (2), and 1,3-dimesityl-4,5-naphthoquino-imidazol-2-ylidene)-gold(i) chloride (3)) were designed, synthesized, and tested for biological activity in a series of human cancer cell lines. The solution phase of complexes 1-3 were assigned using several spectroscopy techniques, including NMR spectroscopic analysis. Complexes 1 and 3 were further characterized by single crystal X-ray diffraction analysis. Electrochemical and spectroelectrochemical studies revealed that quinone reductions are reversible and that the electrochemically generated semiquinone and quinone dianions are stable under these conditions. Complex 1, containing two NHC-quinone moieties (to accentuate exogenous ROS via redox cycling) centered around a Au(i) center (to inactivate thioredoxin reductase (TrxR) irreversibly), was found to inhibit cancer cell proliferation to a much greater extent than the individual components (i.e., Au(i)-NHC alone or naphthoquinone alone). Treatment of A549 lung cancer cells with 1 produced a 27-fold increase in exogenous reactive oxygen species (ROS) which was found to localize to the mitochondria. The inhibition of TrxR, an essential mediator of ROS homeostasis, was achieved in the same cell line at low administrated concentrations of 1. TrxR inhibition by 1 was similar to that of auranofin, a gold(i) containing complex known to inhibit TrxR irreversibly. Complex 1 was found to induce cell death via an apoptotic mechanism as confirmed by annexin-V staining. Complex 1 was demonstrated to be efficacious in zebrafish bearing A549 xenografts. These results provide support for the suggestion that a dual targeting approach that involves reducing ROS tolerance while concurrently increasing ROS production can perturb antioxidant homeostasis, enhance cancer cell death in vitro, and reduce tumor burden in vivo, as inferred from preliminary zebra fish model studies.

Dissociation of the ventilatory and lactate thresholds following caffeine ingestion.

Caffeine ingestion prior to the start of exercise has been shown to have an effect on ventilatory parameters and substrate utilization. Changes in either substrate utilization or ventilatory parameters may influence the determination of the lactate threshold (LT) and/or the ventilatory threshold (VT). Therefore, it was the purpose of this investigation to determine whether the VT and LT occur at similar metabolic rates and what effect caffeine ingestion will have on these two measures. Ten male subjects completed two maximal exercise bouts on the treadmill using a single blind procedure. One trial was performed 45 min after the ingestion of caffeine citrate (CC) in an amount equal to 7.0 mg of anhydrous caffeine.kg-1 body weight. The second trial was performed 45 min after the ingestion of a gelatin powdered placebo (P). Ventilatory parameters were monitored on a breath-by-breath basis, and blood for lactate determination was obtained from an antecubital vein every minute. Maximal oxygen consumption did not differ significantly between the CC (60.3 +/- 5.2 ml.kg-1.min-1) and P (59.7 +/- 5.6 ml.kg-1.min-1) trials. Oxygen consumption (VO2) values during the P trial at the VT (40.2 +/- 6.1 ml.kg-1.min-1) and the LT (38.6 +/- 3.3 ml.kg-1.min-1) were not significantly different (P less than 0.05). During the CC trial, VO2 values at the VT (44.4 +/- 6.6 ml.kg-1.min-1) and the LT (39.7 +/- 5.8 ml.kg-1.min-1) were significantly different. When comparing the VO2 at the LTs between the CC and P trials, there was no significant difference. There was, however, a significant difference in VO2 at the VTs when comparing the two trials. These data demonstrate a dissociation between the VT and LT following caffeine ingestion and suggest that the use of the VT as an indicator of the LT may be inappropriate following ingestion of moderate dosages of caffeine.

Experimental gallstone dissolution with methyl-tert-butyl ether (MTBE) and transcutaneous ultrasound energy.

The simultaneous application of ultrasound energy greatly accelerated the rate of cholesterol gallstone dissolution by methyl-tert-butyl ether (MTBE). In vitro experiments using this treatment showed that a 498-mg stone burden could be dissolved in 19.5 minutes, approximately 100% faster than what could be achieved with MTBE alone. Pigs (n = 13) with surgically implanted gallstones were treated with MTBE and transcutaneously applied ultrasound from a prototype system built for clinical studies. The average stone reduction of all pigs was 470.46 mg +/- 60.44 mg; 91.39% of an average implanted burden of 515.08 +/- 18.03 mg. Control group pigs (n = 9), receiving only an MTBE infusion, showed an average stone reduction of 51.77%. Enzymes indicative of hepatocellular injury showed no significant abnormalities after 6 weeks. Gallbladder ablation with a fibrous remnant (ie, no mucosa, no lumen, patent cystic duct) occurred in 10 (70%) of the pigs.

A large animal model (swine) to study the diagnosis and treatment of cholelithiasis.

Human gallstones were surgically placed into the gallbladders of 200 swine. Eight of these swine were used as a prospective series to verify that the placement and presence of human gallstones in their gallbladders caused no significant pathologic changes in the gallbladder and that the gallstones were not spontaneously dissolved. Although limitations exist, the advantages of this procedure demonstrate that the surgically prepared swine is an appropriate model for controlled in vivo experiments in radiologic imaging or interventional treatment. A 4 F pig-tailed catheter designed for Trocar insertion was developed as a companion to this model.

Detection of surgical lesions of the small bowel by enteroclysis.

Enteroclysis is an examination in which barium is infused directly into the small intestine, and compression radiographs are taken on each segment. This method eliminates many of the inherent limitations of the conventional small bowel follow-through examination. This report concerns 45 patients with 48 small bowel lesions. They were missed on the conventional examination but detected within 3 months by subsequent enteroclysis and confirmed surgically. There were 15 patients with Meckel's diverticula, 7 with obstructive adhesive bands, 5 with Crohn's disease, 5 with blind pouch syndrome (1 with a leiomyoma inside the blind pouch), 2 with other leiomyomas, 3 with metastatic carcinoma, two with primary carcinoma 3 with radiation stricture, two with sinus tract lesions and fistulas, and 1 with another lesion. Improved intubation techniques and better barium mixtures make enteroclysis possible in most hospitals. As surgeons appreciate the value of enteroclysis, they can request this examination for appropriate patients to sooner find many surgical lesions of the small bowel which frequently go undiagnosed.

Lesions missed on small-bowel follow-through: analysis and recommendations.

Forty-two surgically confirmed small-bowel lesions that were not detected by small-bowel follow-through but were demonstrated by enteroclysis were analyzed to determine why small-bowel follow-through had failed to detect them. Thirty lesions (71%) were not seen in retrospect; this was attributed to technical inadequacies. Twelve lesions (29%) were seen in retrospect. Of these, two (17%) of the lesions had been missed originally because of perceptive errors, seven (58%) because of combined perceptive and technical errors, and three (25%) because of interpretive errors. The preponderance of technical errors emphasizes the need for improvements in the small-bowel follow-through technique. More frequent fluoroscopy and more thorough compression of all filled segments, as is performed in enteroclysis, and a decreased reliance on overhead radiographs should decrease the error rate in the routine small-bowel follow-through examination.

Tc-99m diphosphonate imaging in the differential diagnosis of thyroid nodules.

Early Tc-99m diphosphonate (DP) imaging was performed in 122 patients with cold thyroid nodules in an effort to differentiate benign nodules from malignant. Immediately upon completion of the routine 24-hour I-123 uptake and multiview pinhole imaging, Tc-99m DP was injected intravenously and three serial 3-minute anterior images of the thyroid gland were obtained. Follow-up information was available in 85 patients. All cystic lesions had less Tc-99m uptake as compared with the uptake in the normal parts of the thyroid. However, 48 of 50 solid nodules had Tc-99m DP uptake to the same or greater degree than did the normal gland. The other two had mixed pattern on ultrasound examination. Most of the carcinomas (8 of 10) and benign adenomas (15 of 22) had identical appearance on Tc-99m scans, i.e., uptake in the lesion being the same as in the normal thyroid. It appears that by using this technique it is possible to separate solid nodules from cystic, but not benign from malignant.

Ultrasound and computed tomography of the abdomen in the staging and management of testicular carcinoma.

Ultrasound and computed tomography (CT) are ideal for imaging enlarged retroperitoneal lymph nodes. The authors evaluated 290 ultrasound and 188 CT examinations in 136 patients with testicular cancer. Although interpretation of CT was more reproducible than that of ultrasound, there was no significant difference in accuracy of enlarged retroperitoneal lymph node detection between the two modalities. Accuracy improved when both examinations were used and interpreted in combination by a single radiologist. Accuracy rates for ultrasound and CT were equal to those reported for lymphangiography. Lymphangiography and excretory urography are no longer routinely indicated in testicular cancer patients.