Laser photoirradiation of the canine ureteral orifice: comparison between contact and noncontact techniques

We studied the long-term effects of Nd:YAG laser photoirradiation in 17 canine ureteral orifices, comparing results of the contact and noncontact (free-fiber) techniques. The noncontact technique damaged four of eight ureters, causing ureteral obstruction with significant hydronephrosis in three and reflux in one. The amount of energy used correlated with the subsequent appearance of ureteral obstruction; obstruction developed in both cases when 3,000 and 3,300 joules were used but in only one of five cases when less than 2,300 joules were used. In contrast, the contact technique, using 350-800 joules, caused no hydronephrosis and only one case of reflux. Since these animal studies clearly document that the Nd:YAG laser may significantly damage the ureter, particularly when the noncontact technique is used, we recommend that the surgeon consider the contact technique to reduce the risk of ureteral damage and use the smallest amount of energy required for adequate tumor eradication when treating tumors in or near the ureteral orifice.

Preclinical trials using an immunoconjugate of T101 and methotrexate in an athymic mouse/human T-cell tumor model

We made an immunoconjugate (IC) using the anti-CD5 monoclonal antibody T101 and the chemotherapeutic drug methotrexate. Methotrexate was conjugated to T101 using an active ester intermediate, yielding a drug: antibody molar ratio of 12.4. Although T101 immunoreactivity was not significantly altered by conjugation, the IC did not demonstrate antigen-specific cytotoxicity in vitro. Methotrexate activity, assayed in vitro, decreased approximately 100-fold following conjugation. The IC was tested for in vivo efficacy in athymic mice bearing human T-cell (MOLT 4) xenografts. Experimental arms used in the study included i.p. injections of saline, T101, methotrexate, the IC, and a mixture of T101 and methotrexate. Doses ranged from 500 micrograms T101 (17.5 micrograms methotrexate) to 2 mg T101 (70 micrograms methotrexate). Injections were administered only after palpable tumors were established. In experiments at all doses, totaling 66 animals per arm, injection of the IC significantly inhibited tumor growth, and resulted in more tumor regressions and fewer animal deaths than the other four experimental arms. These data demonstrate that the IC promotes a potential advantage over the use of methotrexate through an increase in the therapeutic index.

Isolation and characterization of a fraction from brain that inhibits 1,4-[3H]dihydropyridine binding and L-type calcium channel current

Bovine brain was subjected to acid extraction and several purification steps. A fraction from brain that eluted from C18 reverse-phase columns at 30-35% acetonitrile inhibited [3H]nitrendipine binding to cardiac membranes. Further purification of this fraction on a sizing column in the presence of 40% acetonitrile yielded a low molecular mass fraction (less than 1 kDa) that produced a time- and voltage-dependent inhibition of L-type (but not T-type) Ca2+-channel current in GH3 cells. The results suggest that this fraction contains an endogenous substance that binds directly to slowly-inactivating Ca2+ channels and thereby inhibits current flow.

Superiority of an acid-labile daunorubicin-monoclonal antibody immunoconjugate compared to free drug

We conjugated the chemotherapy agent daunorubicin to the anti-T-cell monoclonal antibody T101 using an active ester intermediate of the acid-labile linker cis-aconitate anhydride. By converting carbohydrate hydroxyl groups on the antibody to amines prior to conjugation, average drug to antibody ratios of 25:1 were achieved with retention of cytotoxicity and only minimal loss of immunoreactivity. The pH sensitivity of the linkage was confirmed. The preparation was cytotoxic for antigen-bearing cells but not antigen-negative cells, even up to 48-h incubation in vitro. Specific cytotoxicity was apparently mediated through the endocytosis of the intact T101 immunoconjugate and the release of the active drug in the lysosomal compartment. Athymic mice bearing human tumor xenografts who received a single injection of the immunoconjugate had less tumor growth and more tumor regressions than animals receiving antibody alone, drug alone, or a mixture of drug plus antibody. This approach appears promising for further investigation.

Adjuvant cyclophosphamide, doxorubicin, and cisplatin chemotherapy for bladder cancer: an update

Seventy-one patients received adjuvant Cytoxan (cyclophosphamide; Bristol-Myers Co, Evansville, IN), Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and cisplatin (CISCA) chemotherapy between March 1981 and March 1986. Patients received adjuvant CISCA chemotherapy if they had pathological findings that were thought to predict for high likelihood of relapse. These included the presence of resected nodal metastases, extravesicular involvement of tumor, lymphatic/vascular permeation of the primary tumor, or pelvic visceral invasion. Sixty-two patients at a similar high risk for recurrence did not receive adjuvant CISCA chemotherapy because they refused, had medical contraindications to therapy, or were not referred for chemotherapy. Two-hundred six patients had a cystectomy performed during the same study period but had none of the poor prognostic features suggesting a high risk for relapse. Sixty-two percent of the patients receiving adjuvant chemotherapy are alive and disease-free for a mean follow-up of 118 weeks (range, 28 to 310 weeks). A survival advantage exists for the adjuvant-treated patients when compared with those with unfavorable pathological findings who did not receive adjuvant chemotherapy (70% v 37%) (P = .00012): no difference exists in long-term disease-free survival for those with favorable pathological findings (long-term disease-free survival 76%) v those who received adjuvant chemotherapy (70%) (P = .33). Adjuvant CISCA chemotherapy prolongs the disease-free survival of some patients following a cystectomy. Patients who benefitted from adjuvant CISCA chemotherapy included those with resected nodal metastases, extra-vesicular involvement of tumor, and direct invasion of the pelvic viscera. Patients not benefitting from adjuvant CISCA chemotherapy in this analysis included those with lymphatic/vascular invasion in their primary tumor as the sole manifestation of high risk for relapse.

Evidence for two conductance/exchange pathways for chloride in rat parotid secretory granules

Electron probe x-ray microanalysis was used to determine that bromide is localized to rat parotid secretory granules at early stages of an in situ Cl/Br washout experiment. Chloride efflux and bromide influx across the secretory granule membrane occurred with a time order of minutes. Since the Cl washout data indicated minimal Cl binding within the granule, and therefore minimal Br binding, the Br localization results suggest the presence of two or more anion conductance/exchange pathways in the granule membrane for the Cl (Br) ion.

Inhibition of human T-cell tumor growth by T101-ricin A-chain in an athymic mouse model

An immunotoxin prepared with the pan-T-cell, anti-CD5, antibody T101, and purified ricin A-chain (RTA) was selectively cytotoxic in vitro, inactivating protein synthesis in the human T-cell line MOLT-4 but not in the human B-cell line 8392. Modulation studies showed that the immunoconjugate was more rapidly cleared from the cell surface than unconjugated T101. Preclinical evaluation of T101-RTA was conducted in a human T-cell, athymic mouse model (Dillman et al., Cancer Res., 45:5632-5336, 1985). Tumor-bearing mice received single i.p. injections of saline, T101, UPC-10 (irrelevant IgG2a), unconjugated RTA, an irrelevant conjugate, UPC-10-RTA, a mixture of T101 plus RTA, or T101-RTA. T101-RTA was the most effective reagent. Thirty animals given injections of 33 micrograms of T101 showed reductions in tumor growth (compared to tumor growth in animals receiving phosphate-buffered saline) but no complete regressions. No decrease in tumor growth was observed with UPC-10. Animals given 12 micrograms of free RTA exhibited reduced tumor growth but only one complete regression was observed; similar results were obtained with mice given 45 micrograms of UPC-10-RTA or a mixture of 33 micrograms of T101 plus 12 micrograms of RTA. Eleven complete regressions and 18 partial regressions were produced in the 46 animals given injections of 45 micrograms of T101-RTA and tumor growth was almost completely blocked. No toxicity was observed in any experimental arm. These results suggest that T101-RTA may be administered safely and with significant antitumor effect.

Hemodynamic effects of dopexamine hydrochloride infusions of 48 to 72 hours' duration for severe congestive heart failure

Dopexamine hydrochloride, a new dopaminergic derivative with potent beta 2-agonist activity, was administered to 10 patients with severe congestive heart failure. Initially, the drug was infused at increasing dosage to achieve a maximal tolerated dose and then titrated to maintain acceptable clinical parameters over the next 48 to 72 hours. Cardiac index increased significantly during the initial titration and at peak effect. Tolerance over the duration of the study was noted in most patients, although further increases in cardiac index could usually be achieved by modest increases in the infusion rate. The peak hemodynamic effect was noted at an average infusion rate of 4.8 micrograms/kg/min. Both stroke volume and stroke work indexes increased during dopexamine hydrochloride infusion in association with decreases in mean arterial, right atrial, mean pulmonary artery and pulmonary capillary wedge pressures, systemic vascular resistance and pulmonary arteriolar resistance. Cardiac output increased by 60% during the infusion and this was out of proportion to the 12% increase in heart rate at peak effect. Most of the increase in cardiac index appeared to be due to the strong vasodilatory profile of the medication producing afterload reduction, with direct inotropic and chronotropic effects contributing to a lesser degree. Drug-related side effects occurred in 4 patients and were easily controlled by down-titration. Dopexamine hydrochloride is an effective and well-tolerated sympathomimetic agent that increases cardiac index while promoting vasodilatation.

Secretory protein 7B2 is associated with pancreatic hormones within normal islets and some experimentally induced tumors

7B2 is a novel neuroendocrine polypeptide which belongs to an entirely new superfamily of proteins. In extension of previous reports on 7B2, these studies concern its expression in endocrine pancreatic tissue. They have been performed using specific antibodies prepared against two distinct synthetic fragments of 7B2 comprising amino acids 23-39 and 117-128 of the native human molecule isolated from pituitary gland. Pancreatic insulin-secreting tumors produced in transgenic mice contain high amounts of 21,500- to 22,000-dalton forms of 7B2. Using light microscopy (immunocytochemical colocalization with different pancreatic hormones), immunoreactivity to 7B2 (IR-7B2) was consistently found within cells producing insulin and glucagon and less consistently within pancreatic polypeptide-containing cells. As in previous reports concerning the brain, adenohypophysis, and thyroid gland, IR-7B2 could be detected by electron microscopy within secretory granules of alpha- and beta-like cells in islets. Furthermore, the IR-7B2 level was higher in extracts of insulin-producing tumors of the transgenic mice that contained the hybrid insulin II gene. In addition, IR-7B2 could be detected immunocytochemically in three of seven tumors produced in the rat by streptozotocin-nicotinamide treatment.

An immunoperoxidase study of renal cell carcinomas: correlation with nuclear grade, cell type, and histologic pattern

We applied a panel of antibodies to formalin-fixed, paraffin-embedded sections of 55 renal cell carcinomas using a three-stage immunoperoxidase technique. The antibody panel included two anti-keratins, AE1 and CAM5.2, anti-epithelial membrane antigen (EMA), anti-vimentin, anti-S100 protein, and the anti-leukocyte marker PD7/26. Forty-eight of 55 renal cell carcinomas expressed keratins. CAM5.2 stained 46 tumors (84%) and AE1 stained 37 neoplasms (67%). AE1 reacted with two CAM5.2-negative tumors. EMA was expressed by 35 carcinomas (64%), including three of the CAM5.2-negative neoplasms. Therefore, using all three antibodies, 50 neoplasms (91%) expressed antigens of epithelial differentiation. Anti-EMA and AE1 were complementary to each other; the combination stained 46 of the carcinomas, comparable with CAM5.2 alone. Vimentin was expressed by 26 tumors (47%), and S100 was expressed by one. PD7/26 did not stain any of the cases. Vimentin expression correlated with nuclear grade; low nuclear grade neoplasms infrequently expressed vimentin, while the converse was true for high nuclear grade tumors. Keratin expression was related to tumor cell type and histologic pattern, as fewer neoplasms of clear cell type and with a solid pattern expressed keratins. In contrast, all papillary and eight of nine (89%) spindled carcinomas expressed keratins.

Systolic anterior motion of the mitral valve as a manifestation of heart transplant rejection

A 65-year-old white man with acute cardiac allograft rejection had a diagnosis made on the basis of clinical presentation and endomyocardial biopsy. The echocardiogram showed systolic anterior motion of the mitral valve during the episode of rejection. There was no systolic anterior motion on the echocardiogram that was done either before or after the episode of rejection.