High affinity block of myocardial L-type calcium channels by the spider toxin omega-Aga-toxin IIIA: advantages over 1,4-dihydropyridines

The peptide omega-agatoxin IIIA (omega-Aga-IIIA) from venom of the funnel web spider Agelenopsis aperta blocks L-type Ca2+ channels in neurons and myocardial cells with high affinity. We report that omega-Aga-IIIA also blocks whole-cell Ca2+ channel currents in guinea pig atrial myocytes. Although other high affinity blockers of L-type Ca2+ channels are available (such as the 1,4-dihydropyridines), omega-Aga-IIIA is a valuable pharmacological tool; omega-Aga-IIIA is the only known ligand that blocks L-type Ca2+ channels with high affinity at all voltages (IC50 approximately 1 nM) and it causes little or no block of T-type Ca2+ channels, unlike the 1,4-dihydropyridines. We use omega-Aga-IIIA to selectively eliminate L-type Ca2+ currents and we show that felodipine blocks T-type Ca2+ currents. Consequently, the toxin is better than dihydropyridines for separating ionic currents through voltage-dependent Ca2+ channels and defining their physiological function.

Block of T-type Ca channels in guinea pig atrial cells by antiarrhythmic agents and Ca channel antagonists

Myocardial cells have two types of Ca channels commonly called T-type and L-type. Whole cell Ca channel currents in guinea pig atrial myocytes can be separated and quantitated by analyzing channel closing kinetics after a brief depolarization (tail current analysis). L-type Ca channels deactivate rapidly when the membrane is repolarized and T-type Ca channels deactivate relatively slowly. Ca channel block by the therapeutically useful Ca channel antagonists is voltage dependent, so it is desirable to study block of both channel types over an extended voltage range. Tail current analysis allows this and was used to study block of both types of Ca channels under identical conditions. Amiodarone, bepridil, and cinnarizine block T-type Ca channels more potently than L-type Ca channels when binding equilibrates at normal diastolic potentials (approximately -90 mV). None of these drugs is a selective blocker of T-type Ca channels because block of L-type Ca channels is enhanced when cells are almost completely depolarized. Although weak block of T-type Ca channels by 1,4-dihydropyridines has usually been reported, we found that felodipine blocks these channels with high affinity. When most T-type Ca channels are inactivated, the apparent dissociation constant (KI) is 13 nM. Felodipine also blocks T-type Ca channels in GH3 cells (a cell line derived from rat anterior pituitary), but KI = 700 nM. Thus, T-type Ca channels in different cell types are pharmacologically distinct. Felodipine can block L-type Ca channels in atrial cells more potently than T-type Ca channels, but block of L-type Ca channels is potent only at depolarized potentials; block of both channel types is comparable at normal diastolic membrane potentials. Felodipine and the 1,4-dihydropyridines isradipine and (-)-202-791 are approximately equipotent at blocking T-type Ca channels, but differ substantially in potency for block of L-type Ca channels. Block of T-type Ca channels may account for some of the pharmacological effects of 1,4-dihydropyridines and for the antiarrhythmic activity of amiodarone and bepridil.

Two types of endometrial papillary neoplasm. A morphometric study

Fourteen cases of Papillary Endometrial Carcinoma (EC) were analyzed by Interactive Computerized Morphometry. Seven cases were diagnosed as well differentiated adenocarcinomas with papillary features (PF) and belonged to a group of EC with associated adenomatous hyperplasia (AH). Seven cases were diagnosed as uterine papillary serous carcinomas (PA) and belonged to a group of EC without associated AH. Two morphometric procedures were used. DRAW for the characterization of individual nuclei (area, perimeter, chord) and NU-MEAS for tissue architectural features (crowding and stratification). Using a stepwise discriminant multifactorial analysis, both methods proved to be accurate for the two diagnostic categories, as shown by the 100% posterior probabilities and by the two diagnostic categories, as shown by the 100% posterior probabilities and by the distances between group means. A doubtful case was analyzed and classified using a K-nearest neighbor procedure, compared to the individual case in the database. The distinction between the two types of papillary EC is important for the differential diagnosis of the two lesions. Well differentiated adenocarcinoma with papillary features is seen usually in the context of a well-differentiated adenocarcinoma, in a group of patients known to have estrogen-related less aggressive tumors. Uterine papillary serous carcinoma was described to have a biological behavior similar to that of papillary ovarian carcinoma and is encountered in a group of patients with more invasive and less differentiated EC2. Computerized interactive morphometry is a valuable method to use for the accuracy of this differential diagnosis in doubtful cases.

A phase II trial of adjuvant cisplatin and doxorubicin in stage I epithelial ovarian cancer

We have treated 26 patients with Stage I ovarian cancer with platinum-based chemotherapy. Patients received 50 mg/m2 cisplatin and 50 mg/m2 doxorubicin every 21 days for six cycles. Eighteen patients had complete surgical staging defined as total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic and aortic node sampling, omentectomy, and cytology. Eight patients had all of the above with the exception of node sampling. The overall median follow-up for the group is 43+ months. Three patients had grade 1 tumors with positive washings or capsule invasion and are disease free with a median follow-up of 53+ months. Of 23 patients with grade 2-3 tumors, 22 are alive and free of disease with a median follow-up of 42+ months. There has been 1 recurrence, at 18 months, in a patient who had complete staging and a grade 2 tumor. The patient recurred with carcinomatosis, documented by laparoscopy. There was no significant hematologic, neurologic, or renal toxicity encountered in any patient. Adjuvant combination chemotherapy is beneficial for selected patients with early-stage ovarian cancer who are at high risk for failure after surgical treatment alone.

The concept of uterine preservation with ovarian malignancies

A 30-year-old woman with bilateral, recurrent, borderline papillary serous cystadenocarcinoma of the ovary was treated with bilateral oophorocystectomy and omentectomy with uterine preservation. Ten years later, through induction of an artificial endometrial cycle and ovum donation, she conceived twins and delivered two healthy infants. Staging exploratory laparotomy at the time of cesarean delivery was negative for malignancy. This case illustrates the value of uterine preservation for cases in which classical teaching has indicated hysterectomy with bilateral salpingoophorectomy.

The inhibition of receptor-mediated and voltage-dependent calcium entry by the antiproliferative L-651,582

L-651,582, 5-amino-[4-(4-chlorobenzoyl)-3,5-dichlorobenzyl]-1,2,3-triazole-4- carboxamide, an antiproliferative and antiparasitic agent previously shown to affect 45Ca2+ uptake into mammalian cells, inhibits both receptor-mediated and voltage-dependent calcium entry in well characterized in vitro systems. Indo 1 fluorescence measurements of cytosolic calcium levels indicate that the drug has no effect on the initial transient release of internal stores of calcium stimulated by fMet-Leu-Phe in rat polymorphonuclear leukocytes. It does decrease the levels maintained subsequently, however, indicating blockage of calcium influx through receptor-operated channels. L-651,582 also blocks the stimulation of leukotriene B4 (LTB4) production by fMet-Leu-Phe with an IC50 = 0.5 micrograms/ml equal to that for calcium entry inhibition. The LTB4 inhibition is likely due to calcium entry inhibition since L-651,582 does not inhibit calmodulin or enzymes producing arachidonate metabolites. L-651,582 also inhibits potassium-stimulated 45Ca2+ influx into GH3 cells with an IC50 of 0.5 microgram/ml, indicating a block of voltage-gated L-type calcium channels. Patch voltage clamp measurements of current through L- and T-type calcium in guinea pig atrial cells also indicate that L-651,582 is a calcium antagonist. Block of L-type calcium channels is voltage-dependent, and the apparent dissociation constant for the high affinity state is 0.2 micrograms/ml. The IC50 for block of T-type calcium channels is 1.4 micrograms/ml. The inhibition of cellular proliferation and the production of arachidonate metabolites by L-651,582 may be the result of the nearly equipotent block of receptor-operated and voltage-gated calcium channels.

Long-term effects of a lifestyle modification exercise program on the fitness of sedentary, obese children

We studied the effects of a lifestyle modification and exercise program on the fitness of 12 sedentary and obese children who were physician-referred into a 1-month YMCA lifestyle modification program. These variables were measured at entry, at the program's conclusion, and 1 and 4 months following conclusion: weight (lbs), sum of 2 skinfolds (mm), number of sit-ups, 9-minute run (total distance in yds), sit-and-reach for flexibility (cm). Total serum cholesterol (mg/dl) was measured only at entry and 4 months following conclusion. We found a NS decrease in weight (124 to 117 lbs) and sum of skinfolds (54 to 40 mm); a significant (p less than 0.01) increase in sit-ups (23 to 35); a significant (p less than 0.05) increase in 9 minute run distance (1201 to 1419 yds); no change in flexibility; and a NS decrease in total serum cholesterol (178 to 155 mg/dl). It was concluded that, while good changes were made, a longer period of time would be required to significantly reduce weight, sum of skinfolds, and total serum cholesterol.

Recurrent cervical squamous cell carcinoma in an ovary following ovarian conservation and radical hysterectomy

This is the second reported case of an ovarian recurrence of Stage I squamous cell carcinoma of the cervix. It occurs following radical hysterectomy, chemotherapy, and radiotherapy. The issue of ovarian conservation is addressed.

Induction chemotherapy followed by radical surgery in cervical cancer

To evaluate the therapeutic potential of cytotoxic therapy in patients with squamous cell carcinoma of the cervix, 28 patients with disease clinically localized to the pelvis were treated with chemotherapy followed by radical pelvic surgery. Treatment consisted of cis-platinum 50 mg/m2, mitomycin C 10 mg/m2, vincristine 1.0 mg/m2, and bleomycin 10 U IM given as a course (over 21 days) of induction chemotherapy followed by radical hysterectomy and pelvic and aortic lymphadenectomy in 26 patients and total pelvic exenteration in 2 patients. The stage distribution of the patients in the study was 4 stage IB, 6 stage IIA, 7 stage IIB, 1 stage IIIA, 11 stage IIIB, and 1 stage IVA. Two patients with stage IIIB cancer were found, at the time of laparotomy, to have carcinomatosis and were excluded from the final evaluation in this study. All patients achieved a clinical and histologic response to chemotherapy. There were 35% complete and 65% partial responses. After chemotherapy, at the time of surgery, 4 patients were found to be histologically free of disease, and the incidence of surgically documented nodal disease after chemotherapy was found to be 32%. There was no significant hematologic or pulmonary toxicity. Induction chemotherapy is well tolerated and may be beneficial in the management of some patients with cervical cancer who are at high risk for failure with conventional treatment.

Ovarian intraepithelial neoplasia demonstrated in patients with stage I ovarian carcinoma

Retrospective review of sections of ovary from 50 patients with stage I, grade 1-3, epithelial ovarian carcinoma was performed to assess presence of cellular and nuclear atypia in noncancerous tissue adjacent to the primary tumor; ovarian tissue from 50 patients undergoing incidental oophorectomy was reviewed as well. Atypia was more common in cancer patients, and finding the combination of nuclear atypia, defined as presence of pleomorphism or irregular chromatin distribution, with cellular atypia, defined as presence of stratification or loss of polarity, allowed separation of cancer and control groups with 98% sensitivity and 100% specificity. Presence of nuclear and cellular atypia was used to define ovarian intraepithelial neoplasia (OIN). If OIN is demonstrated to precede ovarian carcinoma, then it may offer insights into the development of ovarian cancer and may eventually increase the feasibility of screening for this disease.

Clinical features of advanced ovarian mixed mesodermal tumors and treatment with doxorubicin- and cis-platinum-based chemotherapy

Records of 15 patients with stage III and IV malignant mixed mesodermal tumors of the ovary treated between 1977 and 1988 were reviewed. All patients had primary surgery; 13 were given postoperative chemotherapy including doxorubicin and cis-platinum. Median survival for patients receiving chemotherapy is 16 months; 62% were alive at 12 months and 31% at 24 months. Progression-free responses were seen in 85% of treated patients and 55% of these recurred. All recurrences involved the pelvis and were predominantly mesenchymal. Serum CA-125 values accurately reflected tumor presence in 82% of tested patients. Cytoreductive surgery followed by treatment including doxorubicin- and cis-platinum-based chemotherapy is effective in treatment of disseminated ovarian mixed mesodermal tumors, but additional components must be added to achieve durable responses and consistently prolonged survivals.

Therapeutic and metabolic effects of high (greater than 1 g/m2) systemic cumulative doses of cis-platinum in patients with ovarian carcinoma

Adverse effects requiring discontinuation of cis-platinum therapy are usually noted after administration of 600 mg/m2 cis-platinum. Metabolic and therapeutic effects of high (greater than 1 g/m2) cumulative lifetime doses of cis-platinum were reviewed for 20 patients treated with multiple courses of chemotherapy for metastatic, recurrent ovarian carcinoma. Median survival in this selected group is 65 months. Common abnormalities included anemia, hypomagnesemia, and elevated renal functions. No patient required cessation of treatment because of metabolic changes and in no case did the abnormality compromise the patient's activities of daily living. We conclude that, in selected patients, repeated treatment, regardless of cumulative dose, with cis-platinum-based chemotherapy can be well tolerated and may be of therapeutic benefit.

Clinical features and treatment outcome of patients with epithelial carcinoma of the ovary metastatic to the central nervous system

Involvement of the central nervous system with carcinoma of the ovary is being noted with increasing frequency. We report on six patients who presented with central nervous system metastases between 2-61 months after diagnosis. Five patients had elevated serum CA 125 values at the time of diagnosis of central nervous system disease and presenting symptoms, and findings on neurologic examination generally correlated with computed tomography-documented lesions. Eighty-three percent of our patients were symptomatically relieved with a course of 30 Gy given to the whole brain; however, there were no long-term survivors (range 2-24 months). Survival did not appear prolonged in the four patients who received systemic chemotherapy as well as whole-brain irradiation.

Nimodipine block of calcium channels in rat vascular smooth muscle cell lines. Exceptionally high-affinity binding in A7r5 and A10 cells

Calcium channel currents were studied in the A10 and A7r5 cell lines derived from rat thoracic aorta muscle cells. The whole-cell variation of the patch voltage clamp technique was used. Results with each cell line were nearly identical. Two types of Ca channels were found in each cell line that are similar to the L-type and T-type Ca channels found in excitable cells. Nimodipine block of the L-type Ca channels in both cell lines is more potent than in previously studied tissues. The kinetics of nimodipine block are accounted for by a model that postulates 1:1 drug binding to open Ca channels with an apparent dissociation constant (KO) of 16-45 pM. In A7r5 cells, the rate of onset of nimodipine block increases with the test potential, in quantitative agreement with the model of open channel block. The apparent association rate (f) is 1.4 x 10(9) M-1 s-1; the dissociation rate (b) is about 0.024 s-1. In anterior pituitary cells (GH4C1 cells), KO is 30 times larger; b is only twice as fast, but f is 15 times slower. The comparative kinetic analysis indicates that the high-affinity binding site for nimodipine is similar in both GH4C1 and A7r5 cells, but nimodipine diffuses much faster or has a larger partition coefficient into the plasmalemma of A7r5 cells than for GH4C1 cells. Unusually high-affinity binding was not observed in earlier 45Ca flux studies with A10 and A7r5 cells. The model of open channel block accounts for the discrepancy; only a small fraction of the Ca channels are in the high affinity open state under the conditions used in 45Ca flux studies, so an effective binding constant is measured that is much greater than the dissociation constant for high-affinity binding.

Schedule and dosage modification of a cyclophosphamide, hexamethylmelamine, doxorubicin, cisplatin combination chemotherapy regimen for refractory ovarian cancer

A cyclophosphamide, hexamethylmelamine, doxorubicin and cisplatin (CHAP II) regimen produced median survival of 15 and 17 months. All patients had prior chemotherapy, 26 with cisplatin in the former group, and 27 without cisplatin in the latter group. Treatment employed both a novel sequential schedule of cisplatin (usually in the evening) 24 h before cyclophosphamide-doxorubicin and novel stepwise escalation, first of doxorubicin, then of hexamethylmelamine until either nadir white blood counts fell to 1000-1500/mm3 or platelets to 75,000-100,000/mm3. Compared to prior Mount Sinai experience: (i) survival was significantly improved; (ii) with and without prior cisplatin, response rates approached a significant improvement, 12% and 29% complete and 24% and 35% partial. Five of seven additional patients with progression during unmaintained remission also responded, two with pathologically complete remissions. Findings suggest: (i) the importance of maximum dose intensity in ovarian cancer treatment; (ii) the responsiveness of patients failing first line treatment to dose intensive treatment; (iii) the possible importance of schedule, and sequential or circadian timing of cisplatin, and other drugs; (iv) and testing revised clinical criteria of resistance to drugs.

Immune complexes in ovarian carcinoma

Immunodiagnostic screening may improve the survival of ovarian carcinoma by earlier detection and follow-up during treatment. Presently, several ovarian cancer-associated antigens are being utilized to monitor treatment response; a specific and precise test for screening is not currently available. The present study was designed to investigate the presence and clinical significance of circulating immune complexes (IC) in patients with ovarian carcinoma using a polyethylene glycol (PEG) assay. If this assay were to prove clinically useful in patients with ovarian carcinoma, its potential as a screening test would then be evaluated. Serum was obtained from 38 patients with advanced ovarian carcinoma preoperatively, postoperatively, and prior to the administration of a combination chemotherapy regimen containing cisplatin. Five patients had values greater than or equal to 0.10. This test identified only 12.5% of the patients with active disease. Serial sampling failed to reveal any correlation with disease status. Our experience does not support the usefulness of IC levels in studying or treating patients with ovarian carcinoma.

Modulation and intensification of a cyclophosphamide, hexamethylmelamine, doxorubicin, and cisplatin ovarian cancer regimen

For 61 patients with stage III-IV carcinoma of the ovary, chemotherapy consisted first of cisplatin 50 mg/m2 on day 1, cyclophosphamide 500 mg/m2 on day 3, doxorubicin 50 mg/m2 on day 3, and hexamethylmelamine 100 mg/m2 on days 4-15 every 4 weeks. The dosages of doxorubicin and hexamethylmelamine were increased by 60 and 100%, respectively, until the nadir white blood cell counts fell to 1.0 x 10(9)/L. This regimen was less neurotoxic and nephrotoxic than other intensive treatments and produced better therapeutic effects than did the immediate preceding Mount Sinai regimens: 1) The overall median survival was 43 months and progression-free survival was 25 months; 2) the greatest benefit occurred among patients under 50 years of age; 3) regression of large tumors increased in frequency, with 33% of tumors 2-6 cm and 16% of tumors larger than 6 cm converted to either pathologically proved remission or microscopic disease; and 4) for the first time, partial surgical debulking producing residual tumors less than 6 cm in size improved early survival.

Extrauterine pelvic malignant mixed mesodermal tumors. A study of 10 cases with immunohistochemistry

Ten cases of extrauterine malignant mixed mesodermal tumors (MMMTs), nine ovarian, and one pelvic, are presented. One patient had a purely epithelial primary ovarian tumor and MMMT in her recurrent tumors. All the other patients had MMMT in their primary and recurrent tumors. Eight patients had heterologous MMMT including cartilage, striated muscle, and adipose tissue in one case. Two patients had homologous MMMT. All cases presented with metastases involving abdominal organs that were either MMMT or epithelial neoplasms and MMMT. Five patients had recurrent tumors, one extensively involving the spleen. In all recurrent tumors, the mesenchymal components were considerably more abundant than in the primary tumors. Immunohistologic studies of intermediate filaments were performed in seven cases, revealing cytokeratin-positive epithelial structures, vimentin-positive mesenchymal (including cartilaginous) structures, as well as coexpression of cytokeratin and vimentin in anaplastic and giant tumor cells in some cases. Some anaplastic spindle cells, which on routine stains were suggestive of stromal cells, stained positive for cytokeratin, thus identifying their epithelial nature. Desmin staining performed in five cases showed positive staining of rhabdomyoblasts in only one case. Myoglobin staining performed in seven cases was positive in four. The histogenesis from primitive müllerian structures and the natural history of these uncommon neoplasms are discussed in light of the pathological and immunohistochemical data presented.

Ca channels in adrenal glomerulosa cells: K+ and angiotensin II increase T-type Ca channel current

Ca channel currents were studied in freshly dispersed bovine adrenal glomerulosa cells to better understand the control of aldosterone secretion by extracellular K concentration (Ko) and angiotensin II (AII). The whole-cell variation of the patch voltage clamp technique was used. Two types of Ca channels were found. One type is similar to the "T-type" Ca channels found in many excitable cells. These channels deactivate slowly (tau approximately equal to 7 ms at -75 mV) and inactivate rapidly during strong depolarizations. The second channel type activates and inactivates at more positive potentials than the T-type Ca channels and deactivates rapidly. These channels are similar to the "L-type" Ca channels found in muscle and nerve. Our studies provide three reasons for concluding that T-type Ca channels have an important role in mediating stimulus-secretion coupling in response to high K+ or AII: (i) aldosterone secretion and steady-state current through T-type Ca channels are biphasic functions of Ko and both increase in parallel for Ko = 2-10 mM; (ii) nitrendipine blocks the T-type Ca channels and the stimulation of aldosterone secretion by high K+ or AII with similar potency; (iii) AII increases Ca entry through the T-type Ca channels.

Clinical trial of etoposide and cisplatin as salvage therapy in advanced ovarian carcinoma

The combination of etoposide and cis-platinum was evaluated in the treatment of advanced ovarian cancer. Of 13 treated patients, 4 demonstrated complete clinical responses and 3 demonstrated partial clinical responses. The mean progression free interval was 14 months+ for the complete responders and 8.3+ months for the partial responders. The 100 mg/m2 dose of etoposide appears to be critical in attaining response. This etoposide and cisplatinum combination appears to be effective as a salvage regimen in ovarian carcinoma.