The role of Ca(2+)-activated potassium (KCa) channels in the regulation of membrane potential, intracellular free calcium ([Ca2+]i) and contraction was investigated in uterine smooth muscle and myometrial cells. In an immortalized human myometrial cell line, oxytocin increased [Ca2+]i and [3H]inositol phosphate formation. Relaxin attenuated the oxytocin-induced increase in [Ca2+]i. In cell-attached patches, membrane depolarization activated a large-conductance KCa channel (179 +/- 4 pS). Iberiotoxin (IbTX), a potent blocker of "maxi" KCa channels (A. Galvez, G. Gimenez-Gallego, J. P. Reuben, L. Roy-Contanciin, P. Feigenbaum, G. J. Kaczorowski, and M. L. Garcia. J. Biol. Chem. 265: 11083-11090, 1990) produced long closed events (approximately 6 min) in these channels. In agreement with this blockage, IbTX depolarized the cells by 9.8 +/- 2.8 mV and caused a dose-dependent increase in [Ca2+]i with a half-maximal effective concentration of 0.79 nM. IbTX also caused phasic contractions in human myometrial strips and increased both the frequency and force of spontaneous contractions in estrogen-primed rat myometrial strips. Moreover, myometrial contractility was also affected by 1 mM tetraethylammonium, a concentration that blocks uterine smooth muscle KCa channels when applied to the extracellular side (G. J. Perez, L. Toro, S. D. Erulkar, and E. Stefani. Am. J. Obstet. Gynecol. 168: 652-660, 1993). These results strongly suggest that the large conductance KCa channels may actively participate in the control of human myometrial cell membrane potential and [Ca2+].

We have developed a model system for progression ofhuman epithelial cells to malignancy, using a human papillomavirus type 18 (HPV-18)-immortalized human keratinocyte cell line. Cells of cell line FEP-1811 were nontumorigenic in athymic mice through at least 12 passages in culture, but after 32 passages were weakly tumorigenic, producing tumors that regressed. After 62 passages they produced invasive squamous cell carcinomas that grew progressively. The progression to malignancy was associated with an increase in the efficiency of forming colonies in soft agar and with altered differentiation properties. In an organotypic culture system, FEP-1811 cells at passages 12 and 32 exhibited features typical of premalignant intraepithelial neoplasia in vivo, and cells at passage 68 exhibited features consistent with squamous cell carcinomas. No change in copy number of the transfected HPV-18 genome or in the level of expression of the viral transforming gene products E6 and E7 was detected between tumorigenic and nontumorigenic cells. Cytogenetic analysis of cells at early, middle, and late passage levels and cells cultured from tumors revealed that several chromosomal abnormalities segregated with the tumorigenic cell populations.Human papillomaviruses (HPVs) infect epithelial cells at a variety ofanatomical sites. Infection by most ofthe -60 HPV types identified is associated with benign lesions. However, a subset of HPVs, including HPV types 16,18,31,, are frequently detected in tumors of the anogenital track and are suspected etiological agents for such tumors (1). Evidence showing that these same HPV types are also present in histologically normal cells (2) and evidence from epidemiological studies (1) suggest that events additional to HPV infection are necessary for progression to malignant disease.Human epithelial cells, the in vivo target of HPV infections, can be cultured readily in vitro, but no cell culture system has been developed that permits HPV replication. Therefore, models for a role that HPVs may have in the etiology of malignancies that contain them have relied primarily on the results of transfection studies. From such studies, it is clear that the HPVs frequently detected in anogenital carcinomas, such as HPV-16 and -18, exhibit transforming functions in a variety of rodent cell types. HPV types associated more with benign epithelial lesions, such as HPV-6 and -11, have a reduced or no transformation potential (3). Transfection studies of subgenomic fragments of HPV-16 and -18 have identified the E6 and E7 genes as the principal transforming genes (3)(4)(5)(6)(7)(8). In corroboration of these results are studies showing that the E6 and E7 proteins interact with the cellular p53 (9) and retinoblastoma (10) tumor-suppressor gene products, respectively. The transformed phenotypes induced in rodent cells by expression of transfected HPVs or their transforming genes have varied but include cell immortalization (4, 6) as well as transformation to tumorigenicity (11). In contrast, when transfecte...

Two hundred forty-two breast fine-needle aspirates prepared by the Cytyc ThinPrep Processor were compared with aspirates prepared by the conventional smear method. Palpable and nonpalpable mammographic breast lesions were aspirated and the first half of the aspirate was submitted for conventional smears and the second half was rinsed into a proprietary fixative and loaded on the ThinPrep Processor for monolayer slide preparation. The matched pairs were diagnosed and analyzed separately in a double-blinded manner and later paired for comparison. Diagnoses correlated exactly in 62% of cases. The diagnosis of fibroadenoma was made in only 4 of 21 cases on ThinPrep (19% correlation). Semiquantitative analysis of several cytologic features indicated potential pitfalls for accurate diagnosis using the ThinPrep Processor. These included loss of background constituents (such as stroma and adipose tissue), decreased cellularity and single ductal epithelial cells, and decreased cytologic detail including size, shape and nuclear texture. The ThinPrep Processor may play a role in breast fine-needle aspiration, but further investigation is warranted before it is used as a sole preparatory method.

Primary human aortic and myometrial smooth muscle cells (SMCs) were immortalized using an am- Smooth muscle cell (SMC) proliferation in the intima of the aorta and medium-sized arteries is a major factor in the development of human atherosclerosis (1). These SMCs originate from the media and migrate into the intima, where their proliferation results in plaque progression (2, 3). What triggers severe atherosclerosis in individuals who lack known risk factors is not understood and several alternative hypotheses have been proposed (4). Glucose-6-phosphate dehydrogenase isoenzyme typing (5-7) and cytogenetic analysis (8) revealed that many atherosclerotic plaques were composed of a monoclonal population of SMCs. This phenomena was felt to be analogous to the monoclonal proliferation ofbenign neoplastic SMCs in uterine leiomyomas (9-11). Therefore, it has been proposed that a chemical mutagen (12) (37)(38)(39)(40) by the inactivation of host proteins involved in cell cycle control. The E6 protein binds and promotes the degradation of the wild-type p53 protein (41,42), and the E7 protein forms an inactivating complex with the product ofthe retinoblastoma tumor-suppressor gene (43,44). These immortalized SMCs provide material to permit comparative studies of the genotypic and phenotypic properties of normal vessel wall versus atherosclerotic plaque SMCs, and myometrial versus leiomyoma SMCs. MATERIALS AND METHODSPrimary Cell Culture. The human aortic SMCs were a gift from C. M. Giachelli and S. M. Schwartz (University of Washington, Seattle) and originated from the media of two distinct nondiseased thoracic aortas, one from a 2Y-month-old fetus (therapeutic abortion) and the second from a 51-year-old male heart transplant recipient. Under sterile conditions, the aortic media was dissected from the intima and adventitia. The SMCs were isolated by enzymatic digestion (fetal SMCs, 2-4 hr; adult SMCs, 16 hr) with collagenase type 1 (165 units/ml), elastase type III (15 units/ml), and soybean trypsin inhibitor (0.375 mg/ml) and were plated initially in Waymouth's meAbbreviations: HPV16, human papillomavirus type 16; HSV, herpes simplex virus; LTR, long terminal repeat; Neor, neomycin resistance; ORF, open reading frame; Pn, passage level n; SMC, smooth muscle cell; SV40, simian virus 40.tTo whom reprint requests should be addressed at:

Seventy-six cases of well-differentiated lymphocytic lymphoma (WDLL) were reviewed for evidence of additional malignancies. Of these, 18 patients (24%) had one to three further tumors; one half (nine) had squamous cell carcinoma (SCC). The head and neck area was the primary site in all but one case of SCC. The carcinomas were frequently multiple, recurrent, and clinically aggressive. The tumors showed unusually poor differentiation histologically. Actinic keratosis and basal cell carcinomas were frequently associated with SCC. Fifty percent metastasized to cervical lymph nodes replaced by WDLL. Lymphadenopathy due to metastatic SCC may be mistaken for malignant lymphoma alone. In two of five patients (40%), death was directly attributable to SCC. As in renal transplant recipients, SCC of the head and neck in WDLL patients is a common cause of significant complications and mortality requiring aggressive management. Immunosuppression due to WDLL and/or to chemotherapy is likely an important predisposing factor in combination with sun exposure.