Angiotensin II stimulates T-type Ca2+ channel currents via activation of a G protein, Gi

Angiotensin II (ANG II) is the most potent and the most physiologically important stimulator of aldosterone synthesis and secretion from the adrenal zona glomerulosa. Because steroidogenesis by adrenal glomerulosa (AG) cells is mediated in part by Ca2+ influx through T- and L-type Ca2+ channels, we evaluated whether T-type Ca2+ channels are regulated by ANG II. We observe that ANG II enhances T-type Ca2+ current by shifting the voltage dependence of channel activation to more negative potentials. This shift is transduced by the ANG II type 1 receptor. The effect of the hormone is not mediated by Ca2+/calmodulin-dependent protein kinase II (CaMKII) as it is not prevented by CaMKII(281-302), a peptide inhibitor of the catalytic region of the kinase. Rather, this shift is mediated by the activation of a G protein, Gi, because it is abolished by cell pretreatment with pertussis toxin and by cell dialysis with a monoclonal antibody generated against recombinant Gi alpha. This effect of ANG II on T-type Ca2+ channels should increase Ca2+ entry in AG cells at physiologically relevant voltages and result in a sustained increase in aldosterone secretion.

Managed care in gynecologic oncology

We review the recent literature on managed care and its application to gynecologic oncology. Although the literature is limited, we discuss professional agreement contracts, the role of primary care physicians and specialists in gynecologic cancer screening, changes in health care distribution, changes in physician-patient relationships, and cancer research.

Endometrial cancer. Management of high risk and recurrence including the tamoxifen controversy

Risk factors for endometrial cancer include obesity, nulligravidity, late menopause, and anovulatory states. Although diabetes is highly associated with endometrial cancer, hypertension is not an independent variable when correction is made for other factors. Exogenous estrogen increases the risk by at least four times, and smoking is a significant factor. Screening of asymptomatic women may be useful among high risk patients. In addition, racial influence on virulence has recently been identified. Most recurrences of endometrial cancer are identified within 3 years of initial diagnosis. Predictors include ploidy, histologic grade, histologic type, receptor status, and stage. Treatment of recurrence is individualized based on tumor location and receptor status and may involve surgery, radiation therapy, hormonal therapy, or cytotoxic chemotherapy. Tamoxifen has been shown to improve survival among subsets of patients with breast cancer in all stages. A comprehensive literature review and meta-analyses, however, verified an increased risk of endometrial cancer among tamoxifen-treated patients compared with control subjects that may equal the cancer risk from exogenous estrogen exposure. Screening techniques include sonographic assessment of endometrial thickening and vascular patterns, hysteroscopy, and endometrial sampling. A subendometrial cystic proliferation can confuse radiographic evaluation of endometrium, leading to unindicated curettage. A disproportionate incidence of high grade lesions has been reported; however, tamoxifen should not be withheld from patients with breast cancer.

Pelvic exenteration in gynecologic oncology: Experience at the Mount Sinai Center, 1975-1992

Thirty-nine patients underwent pelvic exenteration for gynecologic malignancies at The Mount Sinai Medical Center between 1975 and 1992. Surgical techniques, morbidity, survival, and other variables for patients so treated in two periods, 1975-1984 and 1985-1992, were compared. The primary cancer included squamous cell carcinoma of the cervix, 27; adenocarcinoma of the cervix, 1; squamous cell carcinoma of the vagina, 4; adenocarcinoma of the endometrium, 4; squamous cell carcinoma of the vulva, 2; and adenocarcinoma of the rectum, 1. Median survival was 23.1 months, with a median follow-up of 18 months. Survival was significantly related to status of the lymph nodes (p 0.0004) and surgical margins (p 0.0038). There were two postoperative mortalities, one due to pulmonary embolus and another to myocardial infarction. The ability in the second period analyzed, 1985-1992, to integrate a continent urinary reservoir and supralevator exenteration without colostomy yet not induce increased morbidity or decreased survival, has not been previously reported.

Voltage-gated calcium currents have two opposing effects on the secretion of aldosterone

Using Ca2+ channel blockers with different specificities for L- and T-type Ca2+ channels, we have investigated the roles of these two channel types in K(+)-induced aldosterone secretion. In whole cell voltage-clamp experiments, the spider toxin omega-agatoxin-IIIA (omega-Aga-IIIA) completely blocks L-type Ca2+ channels but has no effect on T-type Ca2+ channels. In contrast, Ni2+ and 1,4-dihydropyridines block both L- and T-type Ca2+ channels. Secretion induced by 7 mM extracellular K+ concentration ([K+]o) is unaffected by omega-Aga-IIIA but is strongly inhibited by Ni2+ or the 1,4-dihydropyridine, nitrendipine. This suggests that physiological increases in [K+]o stimulate aldosterone secretion primarily by enhancing Ca2+ entry through T-type Ca2+ channels. Surprisingly, secretion induced by 60 mM [K+]o is enhanced by omega-Aga-IIIA or Ni2+ and is inhibited by the L-type Ca2+ channel activator BAY K 8644. Nitrendipine (1 nM) also stimulates such secretion, although higher concentrations are inhibitory (concentration inhibiting 50% of maximal response approximately 30 nM). If extracellular Ca2+ concentration is reduced from 1.25 to 0.5 mM, secretion induced by 60 mM [K+]o is enhanced, and Ni2+ or low nitrendipine become inhibitory. Together, these results that L-type Ca2+ currents can reduce steroidogenesis and that the role of these currents was previously misconstrued because 1,4-dihydropyridines modify secretion by multiple mechanisms. Thus Ca2+ entry can function as a negative modulator of steroid secretion.

The stapled continent ileocecal urinary reservoir in the surgical management of gynecologic malignancy

Total cystectomy at the time of radical pelvic surgery for gynecologic malignancies is not uncommon. Many techniques have been developed for urinary diversion including the continent ileocecal urinary reservoir. Twenty-nine patients underwent construction of a continent ileocecal urinary reservoir during the reconstructive phase of an exenterative procedure or for the relief of urinary tract fistula between 1990 and 1993. All procedures were performed using the mechanical stapling devices using metal staples. The right and proximal transverse colon were mobilized to a length of 24 cm. The ileum was divided 8 cm proximal to the ileocecal valve and plicated using the stapling technique. The colonic segment was opened on its antimesenteric border and the reservoir was created by stapling in a fashion to reapproximate the distal ends to each other. The ureters were stented and implanted without tunneling. A large Malecot drain was placed in all the pouches for irrigation of the colonic mucosa in the postoperative period. The ileal stoma was fixed to the anterior abdominal wall as was the anterior surface of the pouch. Operative time ranged from 50 to 150 min for the pouch construction. All patients underwent retrograde contrast study of the pouch 7-10 days postoperatively to verify lack of anastomatic leaks. After recovery, all patients successfully self-catheterized the pouch three to five times daily without difficulty. Of the 29 patients, 17 (59%) had received prior radiation as part of therapy. All patients remained continent at the end of observation. One developed a fistula to the perineum after intraoperative placement of 125I seeds on the pelvic wall. One patient developed pouch stones; endoscopic evaluation of this pouch revealed no evidence of stones at the staple lines and metabolic workup demonstrated hypocitremia as the etiology for the stones. Mean reservoir volume was 550 ml. Mean follow-up is 15.8 months; 5 have expired due to recurrent disease and 19 (83%) remain alive. Only two patients have been admitted for urosepsis due to reflux pyelonephritis. The stapled continent ileocecal reservoir offers benefits to patients undergoing total cystectomy. Using the mechanical stapling devices decreases the operative time and has not resulted in stone formation or pouch leakage. The complications of the procedure are acceptable.

Growth factor expression in normal peritoneum of patients with gynecologic carcinoma

Both epidermal growth factor receptor (EGFR) and HER-2/neu (neu) have been found to be of prognostic importance in epithelial ovarian and endometrial carcinoma, but alterations in proto-oncogene expression of normal tissues of patients with gynecologic malignancies are unknown. Patients (118) undergoing laparotomy for gynecologic indications (78 ovarian cancer, 11 endometrial cancer, 19 benign gynecologic disease, 10 other cancers) had biopsies of normal peritoneum for quantitative assessment of neu and EGFR concentrations. Patients undergoing exploration for gynecologic malignancy were found to have significantly higher median neu expression in the peritoneal biopsies than patients with benign gynecologic disease (P = 0.002). Most patients in this study were found to have ovarian cancer, and median peritoneal neu expression was found to be significantly higher in patients with ovarian cancer versus benign ovarian masses (P = 0.0008) or any benign gynecologic disease (P = 0.004). No significant alteration of unbound EGFR was found in peritoneal biopsies of any of the groups of patients. No associations were found for a history of breast cancer, presence of ascites, or menopausal status with alteration of neu or EGFR expression in normal peritoneum. These findings of altered expression of neu in normal tissues of patients with ovarian cancer are suggestive of the presence of proto-oncogene alterations in loco-regional tissues of the peritoneum, such as might be seen if a paracrine influence existed between tumor and peritoneal cells. Alternatively, the alterations may represent subtle alterations of proto-oncogene expression of germ-line tissues.

Dictyostelium discoideum mutants with temperature-sensitive defects in endocytosis

We have isolated and characterized temperature-sensitive endocytosis mutants in Dictyostelium discoideum. Dictyostelium is an attractive model for genetic studies of endocytosis because of its high rates of endocytosis, its reliance on endocytosis for nutrient uptake, and tractable molecular genetics. Endocytosis-defective mutants were isolated by a fluorescence-activated cell sorting (FACS) as cells unable to take up a fluorescent marker. One temperature-sensitive mutant (indy1) was characterized in detail and found to exhibit a complete block in fluid phase endocytosis at the restrictive temperature, but normal rates of endocytosis at the permissive temperature. Likewise, a potential cell surface receptor that was rapidly internalized in wild-type cells and indy1 cells at the permissive temperature was poorly internalized in indy1 under restrictive conditions. Growth was also completely arrested at the restrictive temperature. The endocytosis block was rapidly induced upon shift to the restrictive temperature and reversed upon return to normal conditions. Inhibition of endocytosis was also specific, as other membrane-trafficking events such as phagocytosis, secretion of lysosomal enzymes, and contractile vacuole function were unaffected at the restrictive temperature. Because recycling and transport to late endocytic compartments were not affected, the site of the defect's action is probably at an early step in the endocytic pathway. Additionally, indy1 cells were unable to proceed through the normal development program at the restrictive temperature. Given the tight functional and growth phenotypes, the indy1 mutant provides an opportunity to isolate genes responsible for endocytosis in Dictyostelium by complementation cloning.

Dictyostelium discoideum mutants with conditional defects in phagocytosis

We have isolated and characterized Dictyostelium discoideum mutants with conditional defects in phagocytosis. Under suspension conditions, the mutants exhibited dramatic reductions in the uptake of bacteria and polystyrene latex beads. The initial binding of these ligands was unaffected, however, indicating that the defect was not in a plasma membrane receptor: Because of the phagocytosis defect, the mutants were unable to grow when cultured in suspensions of heat-killed bacteria. The mutants exhibited normal capacities for fluid phase endocytosis and grew as rapidly as parental (AX4) cells in axenic medium. Both the defects in phagocytosis and growth on bacteria were corrected when the mutant Dictyostelium cells were cultured on solid substrates. Reversion and genetic complementation analysis suggested that the mutant phenotypes were caused by single gene defects. While the precise site of action of the mutations was not established, the mutations are likely to affect an early signaling event because the binding of bacteria to mutant cells in suspension was unable to trigger the localized polymerization of actin filaments required for ingestion; other aspects of actin function appeared normal. This class of conditional phagocytosis mutant should prove to be useful for the expression cloning of the affected gene(s).

Type III omega-agatoxins: a family of probes for similar binding sites on L- and N-type calcium channels

The peptide omega-agatoxin-IIIA (omega-Aga-IIIA) from venom of the funnel web spider Agelenopsis aperta is the only known agent that blocks L-type and N-type Ca channels with equal high potency (IC50 < or = 1 nM). From the same venom, we have purified and sequenced a family of peptides which are homologous to omega-Aga-IIIA but vary over 100-fold in their relative affinity for L-type versus N-type Ca channels. One of these, omega-Aga-IIIB, is 76 amino acids long and identical to omega-Aga-IIIA in 66 positions. We identified two other similar peptides, omega-Aga-IIIC and omega-Aga-IIID, as well as one single amino acid variant of omega-Aga-IIIA and two of omega-Aga-IIIB. The type III omega-agatoxins exhibit similar but distinct activities on voltage-gated Ca channels. omega-Aga-IIIA, omega-Aga-IIIB, and omega-Aga-IIID are nearly indistinguishable in their actions at the insect neuromuscular junction (no effect at 0.1 microM), on atrial T-type Ca channels (no effect at 0.5 microM), and in two assays for synaptosomal Ca channels: they are nearly equipotent inhibitors of 125I-omega-conotoxin GVIA binding to rat brain synaptic membranes (IC50 = 0.17-0.33 nM) and blockers of the K(+)-induced 45Ca2+ influx into chick brain synaptosomes (omega-Aga-IIIB, 1.2 nM; omega-Aga-IIIA, 2.4 nM). In contrast, omega-Aga-IIIA is a better blocker of locust Ca channels (IC50 approximately 10-50 nM) than is omega-Aga-IIIB. Finally, although omega-Aga-IIIA, omega-Aga-IIIB, and omega-Aga-IIID all block atrial L-type Ca channels, omega-Aga-IIIA is over 100-fold more potent. Thus, although type III omega-agatoxins appear to recognize a binding site common to L- and N-type Ca channels, omega-Aga-IIIB and omega-Aga-IIID identify differences between the two channels.

Isolation of myocardial L-type calcium channel gating currents with the spider toxin omega-Aga-IIIA

The peptide omega-agatoxin-IIIA (omega-Aga-IIIA) blocks ionic current through L-type Ca channels in guinea pig atrial cells without affecting the associated gating currents. omega-Aga-IIIA permits the study of L-type Ca channel ionic and gating currents under nearly identical ionic conditions. Under conditions that isolate L-type Ca channel currents, omega-Aga-IIIA blocks all ionic current during a test pulse and after repolarization. This block reveals intramembrane charge movements of equal magnitude and opposite sign at the beginning of the pulse (Q(on)) and after repolarization (Q(off)). Q(on) and Q(off) are suppressed by 1 microM felodipine, saturate with increasing test potential, and are insensitive to Cd. The decay of the transient current associated with Q(on) is composed of fast and slow exponential components. The slow component has a time constant similar to that for activation of L-type Ca channel ionic current, over a broad voltage range. The current associated with Q(off) decays monoexponentially and more slowly than ionic current. Similar charge movements are found in guinea pig tracheal myocytes, which lack Na channels and T-type Ca channels. The kinetic and pharmacological properties of Q(on) and Q(off) indicate that they reflect gating currents associated with L-type Ca channels. omega-Aga-IIIA has no effect on gating currents when ionic current is eliminated by stepping to the reversal potential for Ca or by Cd block. Gating currents constitute a significant component of total current when physiological concentrations of Ca are present and they obscure the activation and deactivation of L-type Ca channels. By using omega-Aga-IIIA, we resolve the entire time course of L-type Ca channel ionic and gating currents. We also show that L- and T-type Ca channel ionic currents can be accurately quantified by tail current analysis once gating currents are taken into account.

Screening for ovarian cancer: the role of noninvasive imaging techniques

In spite of diagnostic and therapeutic improvements the Surveillance Epidemiology and End Results Program data suggest that the overall cure rate for patients with ovarian cancer is 39%. Because of the dramatic difference in cure between patients with local disease (80% to 90%) and those with distant disease (15% to 25%), screening to find early ovarian cancer or its precursors is desirable. Transvaginal ultrasonography is the most efficient, accurate, and least expensive of the imaging modalities (transabdominal ultrasonography, computed tomography, magnetic resonance imaging, radioimmunoscintigraphy) for this purpose. To date, 10,000 women have been screened in three large programs; 11 cancers were detected (10 stage I, one occult stage IIIB) and all have apparently been cured. Doppler flow imaging and morphology index values improve the accuracy of transvaginal ultrasonography. A cost analysis suggests that screening costs are not yet less than treatment costs if there is to be universal screening of 27 million women at risk in the United States. However, for a population with a lifetime risk for ovarian cancer of 1%, screening will save five lives per 2000 patients screened.

Phase II trial of etoposide, carboplatin, and ifosfamide as salvage therapy in advanced ovarian carcinoma

A phase II study combining etoposide with carboplatin and ifosfamide as salvage therapy in advanced ovarian cancer was undertaken. Objective responses were achieved in 37.5% of 16 evaluable patients with a mean progression-free interval of 8.6 months. Stable disease was present in 25% of patients; in 37.5% of patients the disease progressed on salvage. Based on original response to front-line therapy, patients were classified as being platinum-sensitive (group I) or platinum-refractory (group II). Clinical response to salvage therapy was seen in 44.5% of group I patients, but in only 28.6% of group II patients. This difference was not statistically significant. When a more precise definition of platinum sensitivity was applied, clinical responses were seen in 54.5% of group I patients, but no responses were noted among group II patients (p < 0.05). Platinum sensitivity appeared to be an important factor in achieving a response with this regimen. This combination was well tolerated, myelotoxicity being the dose-limiting toxicity encountered. No life-threatening, nonhematologic toxicities were seen. One death occurred secondary to nadir sepsis. The combination of etoposide, carboplatin, and ifosfamide is an active salvage regimen in patients with advanced ovarian carcinoma; however, severe myelotoxicities and inability to produce long-term responses underscore the need for continued trials to find a more durable salvage regimen.

Secondary cytoreduction for ovarian cancer following cisplatin therapy

PURPOSE

This study was undertaken to evaluate the efficacy of secondary surgical cytoreduction in the management of ovarian cancer.

PATIENTS AND METHODS

The cases of 100 patients with recurrent or progressive epithelial ovarian cancer whose initial treatment had been cytoreduction followed by cytotoxic therapy with a cisplatin-based regimen were reviewed. All 100 patients underwent surgery, after recurrence or progression was documented preoperatively, by gynecologic oncologists at the Mount Sinai Medical Center, New York, NY, between 1980 and 1991 with the intention of performing radical tumor reduction.

RESULTS

Sixty-one patients had a secondary cytoreduction that left residual disease less than 2 cm in diameter. The median survival, determined from the date of the secondary cytoreduction to the date of death or last follow-up, is 27.1 months in the optimally treated group and 9.0 months for the 39 patients whose surgery was suboptimal (P = .0001). Other variables associated with statistically significant longer survival, and a significantly higher probability of achieving a successful secondary cytoreduction, included age < or = 55 years at the time of secondary cytoreduction, interval from initial diagnosis to secondary cytoreduction of more than 12 months, residual disease at initial staging laparotomy of less than 2 cm, and a complete clinical response to a cisplatin-based front-line regimen. Multivariate analysis confirms the survival benefit provided by a successful secondary cytoreduction when adjusted for the above variables. There was one postoperative mortality. Ten percent of the successfully cytoreduced patients and 18% of the unsuccessfully cytoreduced patients experienced some degree of postoperative morbidity.

CONCLUSION

These data justify the performance of secondary cytoreductive surgery for patients who develop gross recurrent or progressive ovarian cancer following cisplatin therapy.

Feasibility of intraoperative administration of chemotherapy for gynecologic malignancies: assessment of acute postoperative morbidity

In order to assess the acute effects of the intraoperative administration of intraperitoneal (IP) carboplatin with and without intravenous (IV) doxorubicin in patients with gynecologic malignancies, 25 patients were treated at the conclusion of their surgical procedure. Twenty-three had epithelial ovarian cancer and 2 had advanced endometrial cancer. Twelve patients received IP carboplatin and IV doxorubicin at the conclusion of their primary cytoreduction. The remaining 13 received IP carboplatin alone and consisted of 4 reassessment laparotomies for ovarian cancer, 7 secondary cytoreductions, 1 minilaparotomy for the placement of an IP catheter, and 1 second-look laparoscopy. The median age of the 25 patients was 59 years. Eight patients underwent bowel resections with anastomoses; 2 had ureteral resections and ureteroneocystostomies, 1 required a splenectomy, and 1 underwent a partial hepatic resection. There were no mortalities. Three of the 13 patients who received the IP carboplatin alone had postoperative fevers with no infectious source, which did not delay discharge. No other morbidity was noted in this group. However, 7 patients who received IV doxorubicin along with the IP carboplatin developed severe leukopenia requiring antimicrobial and colony-stimulating factor support. One patient required reexploration for postoperative hemorrhage and also developed a pulmonary embolus. One woman developed postoperative pneumonia. The median hospital stay for the 25 patients was 9 days. Intraoperative chemotherapy can be administered with tolerable immediate adverse effects.

Morphometric differentiation between responsive tumor cells and mesothelial hyperplasia in second-look operations for ovarian cancer

We developed a procedure based on computerized image analysis to establish objective criteria for the differential diagnosis between mesothelial hyperplasia and cancer in peritoneal tissue samples obtained at second-look operations for ovarian cancer. The tumor tissue after chemotherapy was classified as "nonresponsive" if it was found by histologic criteria to be roughly similar to the tumor before chemotherapy and as "responsive" if it was found to be different (small clusters of bland-looking cells with no mitotic activity). Eighty-five samples of tissue had been classified previously by a pathologist into one of the four following groups: ovarian tumor prior to chemotherapy, "responsive" tumor, "nonresponsive" tumor, or mesothelial hyperplasia. Cell profiles of the tissue samples were studied by computerized image analysis using 21 morphometric descriptors derived from the manual tracings of tumor nuclei, including nuclear perimeter, nuclear area, maximal chord, circularity factor, and standard deviations of these descriptors. Size distribution curves of nuclear areas and maximal chords were included in the analysis. A multivariate discriminant analysis confirmed the separation into the four diagnostic groups, accomplished with consideration of the physical descriptors alone, except for some overlapping between groups 1 and 3. The separation between carcinoma and mesothelial hyperplasia was clear in all cases.

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.

Nimodipine block of calcium channels in rat anterior pituitary cells

1. Ca channels were studied in the GH4C1 clonal cell line derived from rat anterior pituitary cells. The whole-cell variation of the patch-electrode voltage-clamp technique was used. 2. Two types of Ca channels were found. One type ('slowly inactivating' channels) is insensitive to changes in holding potential, does not inactivate during test pulses lasting several seconds, and deactivates very quickly upon repolarization. For holding potentials less than -40 mV, a second type of Ca channel is available for opening. This population ('transient' channels) differs from the first type in that it activates at more negative potentials, inactivates rapidly with either Ca or Ba as the charge carrier, deactivates about 10 times more slowly upon repolarization, and is less selective for Ba over Cs. 3. Nimodipine preferentially blocks the slowly inactivating channels. Block of these channels is time- and voltage-dependent, such that block is maximized by long depolarizations. 4. A comparison of the voltage dependence of steady-state nimodipine block with the voltage dependence of channel activation indicates that channel block is directly proportional to the number of open channels. The results are accounted for by a model that postulates 1:1 high-affinity drug binding to open Ca channels. The apparent dissociation constant for binding to open channels is 517 pM. Similar binding constants were previously reported for the inhibition of high-K-induced hormone secretion and high-affinity ligand binding of [3H]nimodipine to isolated plasma membranes. 5. 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 is about 9.6 X 10(7) M-1 s-1; the dissociation rate is about 0.050 s-1. At therapeutic concentrations (less than 10 nM) nimodipine block takes many seconds to reach equilibrium. 6. Nimodipine should have little effect on stimulus-secretion coupling in healthy pituitary cells in vivo because: (a) the drug binds very weakly to the transient channels that are open at normal resting potentials, and (b) negligible high-affinity binding occurs during spontaneous activity because the onset of block is very slow.

Prognostic factors: cisplatin regimens for patients with ovarian cancer after failure of chemotherapy

For 129 ovarian cancer patients failing prior chemotherapy, overall clinical response rates were: 21% with cisplatin, 36% with cisplatin plus doxorubicin, 52% with cyclophosphamide added to the two drugs, and 44% with hexamethylmelamine added to the three drugs. Median survival was six or seven months in each trial. Twenty-five percent of the patients survived nine months with cisplatin and 14 to 16 months with each of the three combinations. Characteristics associated with best rate of response included: performance status 1 (completely ambulatory), age greater than or equal to 50, residual tumor less than or equal to 5 cm, and two or less prior cytotoxic drugs. In multivariate analyses, performance status dominated, although age and possibly treatment (cisplatin versus others) were significant. With performance status removed from the model, all of the remaining factors became significant. Factors associated with best survival included: performance status 1, tumor size less than or equal to 5 cm, and complete or partial response. In a multivariate analysis for survival, performance status entered the model. In a series of analyses with performance status removed, tumor size or response entered the model. These findings provide reasons to study both treatment with cisplatin before disease progression reduces the number of favorable characteristics and systematic second attempts at debulking surgery.

Catheter complications associated with intraperitoneal chemotherapy

Intraperitoneal administration of chemotherapy in ovarian carcinoma is currently under investigation. Numerous recent publications have described clinical studies employing a variety of chemotherapeutic drugs. Little information exists regarding the delivery systems employed or the complications encountered. This study reviews our experience with "single-use" and "long-term" catheters. Thirty-three catheters were placed in 28 patients. Of these catheters, 12 were long-term Tenckhoff catheters and 21 were temporary single-use catheters. Both types of catheters had complications associated with their usage. However, there was a dramatic difference in the number and severity of complications when the two groups were compared. Sixty-seven percent of the Tenckhoff catheters were associated with complications. Nineteen percent of the patients with single-use catheters experienced complications. This 19%, however, represented only 3.8% of the total number of single-use catheter insertions. In our hands, the temporary percutaneous approach has been a safe one, which is technically easy to perform with minimal complications.

Histologic correlates and virulence implications of endometrial carcinoma associated with adenomatous hyperplasia

The association of endometrial carcinoma (EC) with endocrinopathies manifested by obesity, nulliparity, and/or increased estrogen levels of exogenous or endogenous estrogens is now well-known. EC is also seen in patients without these findings. Are these different cancers? Seventy-four cases of EC were reviewed and classified into two groups: group I, with associated adenomatous hyperplasia (AH), 31 cases; and group II, without associated AH, 43 cases. Group I included more well-differentiated and less invasive carcinomas; histologically, the pattern was glandular in all cases. In Group II, the EC were less well-differentiated, more invasive, and included, besides adenocarcinomas, clear-cell, papillary, and anaplastic carcinomas with giant tumor cells. Squamoid features were found in both groups. The possible existence of two types of EC, a hormonal-dependent EC associated with AH (which is believed to result from hyperestrogenism, and to have a better clinical prognosis), and an "independent" EC, not associated with AH, is discussed.

Surgical considerations in ovarian cancer

A primary consideration for effective management of ovarian cancer is distinguishing patients with advanced bulky disease from those with other stages of disease. It is important to determine whether a tumor is confined to one ovary or is more wide-spread. Surgical management includes removal of both ovaries and tubes, the uterus, omentum, and bulk of the disease. The degree of bulk reduction achieved significantly impacts on survival. Conservation is justified in some cases. Intraperitoneal treatment with platinum-based chemotherapy postsurgery appears to substantially benefit patients with minimal residual disease. In a study comparing two catheter methods, fewer complications were noted with the disposable single-use catheter than with the implanted catheter. Surgical endstaging can definitively identify cured patients. However, it is a difficult procedure and is contraindicated in patients with severe intercurrent illness, previous extensive radiotherapy, and an obliterated peritoneal cavity.

Elevation of serum CA 125 prior to diagnosis of an epithelial ovarian carcinoma

In a single fortuitous case it has been possible to measure serum levels of CA 125 during 3 years preceding the diagnosis of an epithelial ovarian carcinoma. CA 125 levels were elevated 10-12 months prior to clinical detection of the malignancy. CA 125 deserves further evaluation as a marker for early detection of ovarian cancer.

A dihydropyridine (Bay k 8644) that enhances calcium currents in guinea pig and calf myocardial cells. A new type of positive inotropic agent

Bay k 8644 is a structural analog of nifedipine with positive inotropic activity. The mechanism of drug action was evaluated by measuring the effects of Bay k 8644 on twitch tension, action potential configuration, and calcium channel currents in myocardial cells. Bay k 8644 increases twitch tension in guinea pig atria without changing the time course of tension development. The drug does not occlude the effect of isoproterenol on twitch tension. The effects of Bay k 8644 on atrial twitch tension are highly dependent on the frequency of stimulation. Maximal inotropic effects are observed at approximately 0.5 Hz, but no inotropic effect occurs at 0.003 Hz (a rested-state contraction). Since positive inotropic effects only occur with frequent electrical stimulation, they are not due to an intracellular action or to mechanisms that elevate cell calcium in quiescent muscle, such as inhibition of the Na,K-ATPase. Bay k 8644 increases the action potential duration of calf ventricular muscle and Purkinje fibers. Effects on action potential duration are occluded by 1 microM nisoldipine, which specifically blocks calcium channels. The interaction of Bay k 8644 with calcium channels in calf Purkinje fibers was studied using the two-microelectrode voltage clamp technique. Strontium was used as a charge carrier to minimize current through calcium-activated channels and to avoid changes in calcium conductance due to changes in intracellular calcium. Bay k 8644 increases strontium currents and alters the time- and voltage-dependence of channel opening. The greatest percent increase in strontium current occurs for weak depolarizations. For strong depolarizations, strontium current is increased most at the beginning of a test pulse. The drug-induced changes in calcium channel gating are inconsistent with a calcium- or cyclic adenosine monophosphate-mediated effect, and indicate a novel mechanism of action on calcium channels. Thus, Bay k 8644 is the first positive inotropic agent shown to act specifically and directly on calcium channels.

Endocervical carcinoma: a study of 23 patients with clinical-pathological correlation

Twenty-three patients with endocervical carcinomas diagnosed at the Mount Sinai Medical Center during the last 5 years were reviewed (clinical history and histologic material). The tumors were endocervical-type adenocarcinomas, adenosquamous carcinoma, mucinous (colloid), papillary, and clear cell carcinomas. Eight associated carcinomas in situ were found. Younger patients tended to have more adenosquamous carcinomas, perhaps related to the frequency of squamous metaplasia in sexually active women. Twenty-two out of twenty-three patients were multiparous, many of them grand multiparas. In two patients the tumor followed parturition, and in two patients it was found in the cervical stump. No association with oral contraceptives was found. Multiparous women seem to be at increased risk for this malignancy. The early detection of endocervical carcinoma is based on the recognition of dysplasia and adenocarcinoma in situ in the biopsy material. This is of particular significance in the endocervical cancer because its location often prevents early detection.