[Cost-effectiveness analysis of fracture liaison services in Catalonia]. / Análisis de coste-efectividad de las Unidades de Coordinación de Fracturas en Cataluña.

OBJECTIVE: To assess the cost-effectiveness of Fracture Liaison Service (FLS) compared to the standard of care for secondary prevention of fragility fractures form the perspective of the Catalan Health Service. METHODS: Cost-utility assessment through a Markov model that simulated disease progression of a patients' cohort candidates to initiate antiosteoporotic treatment after a fragility fracture. A time horizon of 10 years and a 6-month duration per cycle was established. Clinical, economics and quality of life parameters were obtained from the literature and derived from four Catalan FLS. The Catalan Health Service perspective was adopted, considering direct health costs expressed in 2022 euros. A 3% discount rate was applied on costs and outcomes. Uncertainty was assessed through multiple sensitivity analyses. RESULTS: Compared to the standard of care, FLS would promote antiosteoporotic initiation and persistence, reducing the incidence and mortality associated with subsequent fragility fractures. This incremental clinical benefit was estimated at 0.055 years and 0.112 quality-adjusted life years (QALYs) per patient. A higher cost (€1,073.79 per patient) was estimated, resulting into an incremental cost-utility ratio of €9,602.72 per QALYs gained. The sensitivity analyses performed were consistent, corroborating the robustness and conservative approach of the base-case. CONCLUSIONS: The introduction of FLS for the secondary prevention of FF would represent a cost-effective strategy from the Catalan Health Service perspective.

Spironolactone use in patients with heart failure.

BACKGROUND: The addition of spironolactone, an aldosterone antagonist, to standard therapy can reduce the risk of both morbidity and mortality in patients with severe heart failure. OBJECTIVE: To evaluate the use of spironolactone in class III and IV heart failure patients in four urban teaching hospitals. METHODS: We conducted a concurrent medical record review of 163 patients with documented heart failure admitted to a general medicine service over a 5-week period. Data retrieved included patient demographics, heart failure class, left ventricular ejection fraction, spironolactone contraindications, spironolactone use, dose and frequency, and other heart failure medication use, dose and frequency. All data reflected patients' baseline status. RESULTS: Our patient population was 80% white people, 61% male, with a mean age of 70 years (35-99). A total of 114 had class III or IV heart failure (70%). Angiotensin-converting enzyme inhibitors or appropriate alternative were prescribed in 117 (72%) patients, whereas beta-blockers were used in 121 (74%) patients. Fifty-seven patients met spironolactone ideal candidate criteria. Of these, eight (14%) were appropriately prescribed spironolactone. CONCLUSIONS: Three years after publication of the Randomized Aldactone Evaluation Study, spironolactone is underutilized in the treatment of heart failure. Results of this study indicated that the majority of patients in class III or IV heart failure were not prescribed spironolactone. Improvements in spironolactone prescribing are needed.

Historia del Instituto de Investigaciones Cardiológicas Alberto C. Taquini en su 60 aniversario / History of Instituto de Investigaciones Cardiológicas Alberto C. Taquini in its 60th anniversary

The Instituto de Investigaciones Cardiológicas (ININCA) was founded by Alberto C. Taquini in 1944 and directed by him during more than 50 years, until his death in 1998. The Institute was (and still is) dedicated to research in connection with CONICET (National Research Council) and to teaching within the Faculty of Medicine of the University of Buenos Aires. From the very beginning research was centered on hypertension, hypoxia and hemodynamic adaptations, renal physiology and electrolytes, arterial wall, cardiac metabolism, myocardial pharmacology and regulation of the circulation by the central nervous system. On the basis of Taquini's autobiographical notes, the experiments are reported which eventually led to the discovery of hypertensin, angiotensin and their relation with renin, together with the discussions promoted by the diverse hypotheses proposed by both national and international groups of investigators as the mechanism of hypertension. Taquini also played an important role in promoting science at national levels including his role as the first Secretary of Science and Technology from 1968 to 1971. He believed that scientific research is something more than planning and producing, that it also involves creating knowledge. As such he made many contributions to science, formed many disciples, and directed an Institute which is demonstrating its continuity.

El Instituto de Investigaciones Cardiológicas (ININCA) está unido a la figura de quien fuera, desde sufundación, director por más de 50 años: Alberto C. Taquini. Allí se desarrolló (y se desarrolla) investigacióny docencia. Se estudiaron, desde el inicio, la hipertensión arterial, la hipoxia y las adaptaciones hemodinámicas, la fisiología del riñón y los electrolitos, la pared arterial, el metabolismo cardíaco, la farmacología del miocardio y el papel regulador del sistema nervioso central en la circulación. Se relatan aquí, a través de notas autobiográficas de A.C. Taquini, los experimentos y las discusiones que culminaron con el descubrimiento de la hipertensina, las demostraciones experimentales sobre la renina, que constituyeron objeciones básicas a hipótesis entonces prevalentes, y también algunos juicios y pensamientos expresados por A.C.Taquini sobre el papel y el futuro de la ciencia, en nuestros países y en el primer mundo. Desde 1972 la labor del Instituto se centró casi exclusivamente en la investigación básica y pasó a asociarse al CONICET. Decía Taquini que la investigación científica es algo más que proyectar y producir. Es algo más que una factoría de conocimientos:es crear. El mejor ejemplo de ello son sus contribuciones a la ciencia, las de su grupo y de sus discípulos, y lacontinuidad del Instituto que sigue hoy en ese camino.

Historia del Instituto de Investigaciones Cardiológicas Alberto C. Taquini en su 60 aniversario / History of Instituto de Investigaciones Cardiológicas Alberto C. Taquini in its 60th anniversary

The Instituto de Investigaciones Cardiológicas (ININCA) was founded by Alberto C. Taquini in 1944 and directed by him during more than 50 years, until his death in 1998. The Institute was (and still is) dedicated to research in connection with CONICET (National Research Council) and to teaching within the Faculty of Medicine of the University of Buenos Aires. From the very beginning research was centered on hypertension, hypoxia and hemodynamic adaptations, renal physiology and electrolytes, arterial wall, cardiac metabolism, myocardial pharmacology and regulation of the circulation by the central nervous system. On the basis of Taquinis autobiographical notes, the experiments are reported which eventually led to the discovery of hypertensin, angiotensin and their relation with renin, together with the discussions promoted by the diverse hypotheses proposed by both national and international groups of investigators as the mechanism of hypertension. Taquini also played an important role in promoting science at national levels including his role as the first Secretary of Science and Technology from 1968 to 1971. He believed that scientific research is something more than planning and producing, that it also involves creating knowledge. As such he made many contributions to science, formed many disciples, and directed an Institute which is demonstrating its continuity.(AU)

El Instituto de Investigaciones Cardiológicas (ININCA) está unido a la figura de quien fuera, desde sufundación, director por más de 50 años: Alberto C. Taquini. Allí se desarrolló (y se desarrolla) investigacióny docencia. Se estudiaron, desde el inicio, la hipertensión arterial, la hipoxia y las adaptaciones hemodinámicas, la fisiología del riñón y los electrolitos, la pared arterial, el metabolismo cardíaco, la farmacología del miocardio y el papel regulador del sistema nervioso central en la circulación. Se relatan aquí, a través de notas autobiográficas de A.C. Taquini, los experimentos y las discusiones que culminaron con el descubrimiento de la hipertensina, las demostraciones experimentales sobre la renina, que constituyeron objeciones básicas a hipótesis entonces prevalentes, y también algunos juicios y pensamientos expresados por A.C.Taquini sobre el papel y el futuro de la ciencia, en nuestros países y en el primer mundo. Desde 1972 la labor del Instituto se centró casi exclusivamente en la investigación básica y pasó a asociarse al CONICET. Decía Taquini que la investigación científica es algo más que proyectar y producir. Es algo más que una factoría de conocimientos:es crear. El mejor ejemplo de ello son sus contribuciones a la ciencia, las de su grupo y de sus discípulos, y lacontinuidad del Instituto que sigue hoy en ese camino.(AU)

Reelin-immunoreactive neurons in the adult vertebrate pallium.

Reelin, an extracellular matrix protein, plays a crucial role in cortical development. By using Reelin-immunohistochemistry in different vertebrates (fish, amphibians, reptiles, and mammals : insectivores, odontocetes, rodents, carnivores and man) we show here that Reelin is also expressed by a variety of neurons in the adult pallium. In the everted telencephalon of the zebrafish, Reelin-positive neurons are widely distributed over the dorsal pallium. In land vertebrates, the most consistent and evolutionary conserved location of Reelin-expressing neurons is in the cell-sparse molecular layer associated with laminated cortical organization. We describe an additional heterogeneous population of Reelin-positive neurons outside the molecular layer, the location and distribution of which are more variable, and which may reflect major evolutionary changes in cortical architecture. In squamate reptiles, the Reelin-negative main cell layer is flanked by a superficial and a deep plexiform layer which both contain Reelin-expressing neurons. In mammals, Reelin-positive interneurons are dispersed throughout layers II--VI; the human neocortex is particularly poor in Reelin-positive interneurons. Reelin is also expressed by large stellate and modified pyramidal neurons in layer II of the mammalian entorhinal cortex, and in the superficial lateral cortex of lizards. Examination of this cell population (layer II Pre-alpha) in human brains of different age groups points to a decrease in Reelin-expression in the course of adult life.

Homozygous and heterozygous gly-188-Arg mutation of the rhodopsin gene in a family with autosomal dominant retinitis pigmentosa.

Autosomal dominant retinitis pigmentosa (adRP) may be caused by point mutations in the rhodopsin gene in up to 20% of Spanish families. Most of the rhodopsin mutations causing adRP have been reported in the heterozygous state. We describe a patient with adRP who is homozygous for a missense mutation at codon 188 in the second intradiscal domain of rhodopsin. All her sons are heterozygous for the mutation and show an RP phenotype suggesting complete penetrance for this mutation. The homozygous carrier of the mutation Gly-188-Arg in the rhodopsin gene showed a later subjective onset of symptoms than the heterozygotes, suggesting that the photoreceptor degeneration induced by the mutation is not dramatically influenced by mutant allele dosage.

Transforming activity of the E6 gene of HPV-11gt in NIH 3T3 and REF 52 cells: correlation with the level of E6 transcription.

Among human papillomavirus (HPV) types, clinical association with benign vs malignant lesions correlates with the ability of the corresponding oncogenes to transform cells in vitro. However, even though HPV-11 is considered a low-risk type, we have reported previously that the E5a oncogene of HPV-11gt is capable of transforming NIH 3T3 cells in culture. In this study, we found that HPV-11gt E5a and E6 oncogenes have the ability to transform NIH 3T3 and the rat embryo fibroblast line REF 52. Cells were transfected independently with expression plasmids containing the HPV-11gt E5a or E6 oncogenes or both plasmids simultaneously to examine potential interactions. Cells containing these plasmids were phenotypically transformed and had an accelerated doubling time, loss of contact inhibition of growth, and loss of anchorage dependence for cell division. Independent cell lines containing the HPV-11gt E6 gene exhibited variable levels of phenotypic transformation that correlated with the HPV-11gt E6 gene content. The degree of phenotypic transformation could be increased by elevating the level of transcription of the E6 gene, indicating that there is a dose response effect for transformation in this system. These results suggest that increased expression of E6 may be an important factor in malignant progression of naturally occurring tumors.

Characterization of human papillomavirus type 57b: transforming activity and comparative sequence analysis as probes for biological determinants associated with high-risk oncogenic viruses.

The association of human papillomavirus type 57 (HPV-57) with premalignant and malignant tumors of the nasal cavity was previously reported (Wu et al., Lancet 341, 522, 1993). We determined the complete nucleotide sequence of HPV-57b (GenBank 37537), which was molecularly cloned from a benign fungiform papilloma, and compared it with other HPV types and HPV-57a, which was cloned from an inverted papilloma of the maxillary sinus by de Villiers et al. (Virology 171, 248. 1989). Comparative and phylogenetic analysis of amino acid sequences of the HPV-57b oncogenes E5, E6, and E7 were performed with HPV-6, 11, 16, and 18. Phylogenetic trees using the Jotun-Hein algorithm indicated a closer relationship of HPV-57b E5 and E7 with corresponding genes of HPV-18. Signature pattern analysis of these two oncogenes was also in agreement with a closer relatedness to HPV-16 and 18 oncogenes, which are associated with a high risk for malignant progression. Compared with 7861 bp of HPV-57a, HPV-57b had 7868 bp as well as differences in the restriction enzyme sites and the open reading frames, including at least five additional ones. To investigate the oncogenic potential of HPV-57b, NIH 3T3 and REF52 cells were cotransfected with two plasmids: pKP54. HPV-57b, which contains the HPV-57b genome, and pMT.neo.1, which confers resistance to G418. After selection in culture medium containing G418, 58% of the G418r NIH 3T3 colonies and 47% of the G418r REF52 colonies exhibited morphological transformation. These results indicate that the transcriptional regulatory elements and the oncoproteins of HPV-57b are active in vitro to induce cellular transformation, as are other high-risk HPV types.

A new irregular phenylpropanoid from Apollonias barbujana.

In addition to the known compounds (+/-)-threo-guaiacylglycerol and the phenethyl alcohols, 3-methoxy-4-dihydroxyphenethyl alcohol and 3,4-dimethoxyphenethyl alcohol, a new irregular phenylpropanoid 2-(3-methoxy-4-hydroxyphenyl)-1,3-propanediol was isolated from the ethanolic extract of the leaves of Apollonias barbujana (Lauraceae). Their structures were elucidated on the basis of spectroscopic methods and chemical transformations.

KBM-7, a human myeloid leukemia cell line with double Philadelphia chromosomes lacking normal c-ABL and BCR transcripts.

A human myeloid leukemia cell line, KBM-7, was developed from a patient in the blastic phase of chronic myeloid leukemia (CML). We characterized its morphology, immunophenotype, cytogenetics, and proliferative capacity. Developed in the absence of exogenous lymphokines, KBM-7 in vitro cloning capacity actually decreased when colony-stimulating factors were added. The cells had an aberrant immature myeloid phenotype, a doubling time of 22 h in suspension cultures and a high cloning efficiency in semisolid system (24 +/- 3)%. Early passages contained one near-haploid (predominant) and one hyperdiploid stem line. Gradually the hyperdiploid stem line became predominant, reaching an average of 49 chromosomes per cell. Cells from passage 89 had two Philadelphia chromosomes [t(9;22)(q34;q11)] and lacked normal copies of chromosomes 9 and 22. Detailed molecular characterization of the breakpoint in the t(9;22)(q34;q11) revealed that KBM-7 had the BCR 2/ABL II splice junction. The cells had high protein kinase (p210BCR-ABL) activity and carried two identified variants of an ABL-BCR message. There was no evidence that normal BCR or c-ABL messages were expressed, assessed with the reverse-transcriptase polymerase chain reaction. When KBM-7 cells were heterotransplanted into nude mice without immunosuppressive pretreatment, one of three mice injected with 1 x 10(7) cells and all mice injected with 1 x 10(8) cells developed slowly growing granulocytic sarcomas within 6-8 weeks. These tumors were locally invasive but did not metastasize. We conclude that the KBM-7 cell line will be of value for investigating molecular events underlying neoplastic transformation in CML, in particular for studying the effects of BCR-ABL and ABL-BCR on the proliferation of CML cells in the absence of normal BCR and c-ABL messages.

Lignan models as inhibitors of Phanerochaete chrysosporium lignin peroxidase.

The lignan 8,8'-bis-(methylenedioxy)cinnamic acid (BMDCA) is a powerful competitive inhibitor (K1 = 2.0 microM) of the lignin peroxidase (LiP) from Phanerochaete chrysosporium and of the extracellular peroxidase of Phlebia radiata (I0.5 = 10 microM). BMDCA derivatives with the same double bond system also inhibited these enzymes to some extent. If the double bonds were hydrogenated, the inhibitory effect was lost. HRP-VIII and HRP-XI were slightly inhibited by BMDCA (I0.5 > 50 microM) and two plant peroxidases described as efficient lignan synthesizers were unaffected. Liquid cultures of P chrysosporium did not discolour the dve Poly R478 when 250 microM of BMDCA was present.

Prenatal haloperidol induces a selective reduction in the expression of plasticity-related genes in neonate rat forebrain.

Haloperidol, a dopamine receptor antagonist clinically used as an antipsychotic drug, induces long-term deleterious effects in offspring development when administered prenatally. However, the basis for this overall response to the drug remains unknown. Here we describe that prenatal administration of haloperidol in rats induces a drastic and selective reduction in the expression of plasticity-related genes in neonate forebrain, but not in mesencephalon. GABAergic and enkephalinergic markers such as glutamic acid decarboxylase activity and mRNA, and preproenkephalin mRNA were also diminished in forebrain. However, the expression of other genes such as epidermal growth factor-receptor, glial fibrillary acidic protein, and several proto-oncogenes (src, fos and myc), and a cholinergic marker such as choline acetyltransferase activity were unaltered. In addition, haloperidol promoted a significant decrease in mitotic cell number and cellular density in the striatum, one of the forebrain regions with the highest dopamine receptor density. These findings suggest that prenatal dopamine receptor occupancy may be a critical factor in controlling the development of forebrain target cells through mechanisms involving changes in the expression of plasticity-related genes.

Detection of subgroups of chronic B-cell leukemias by FMC7 monoclonal antibody.

Monoclonal antibody FMC7 detects subgroups of B-cell leukemias that have arisen from cells in late stages of B-cell maturation. FMC7 was studied by flow cytometry on cell samples from 192 patients with a diagnosis of chronic lymphocytic leukemia (CLL) or lymphoma. The leukemic cells from 16 patients were reactive with this antibody. These 16 cases were evaluated for other surface markers, morphology of cells, and clinical characteristics. Of the 16 patients, 14 had cells that strongly expressed surface immunoglobulin (SIg). This is atypical of CLL cells, which characteristically show weak expression of SIg. Eleven cases had kappa and five had lambda light chain. All patients' cells had consistently brighter CD20 expression than that of CD19. Fourteen patients had expression of CD5 on their leukemic cells. One patient had more than 55% prolymphocytes, meeting the criteria of prolymphocytic leukemia (PLL), two patients had CLL in prolymphocytic transformation (CLL/PL), and two other patients were classified as having a paraimmunoblastic variant of small lymphocytic lymphoma based on a high number of paraimmunoblasts and on the histologic features. Another nine patients had immature lymphoid cells distinct from prolymphocytes or paraimmunoblasts on morphologic study. The immature cells were variable in size, and the nuclear chromatin was less clumped than that of prolymphocytes. The histologic diagnoses in four of these cases were consistent with mantle cell lymphoma. Splenomegaly was observed in 11 patients (69%), and 11 patients had advanced Rai 3 or 4 disease. Among 10 patients treated with fludarabine, five responded to therapy. Monoclonal antibody FMC7 is useful for identifying a group of atypical variants of CLL, PLL, and other B-cell lymphomas in leukemic phase that can be easily confused with CLL. Careful attention to the cell morphology and histologic features is important for the differential diagnosis of FMC7-positive, B-cell lymphoproliferative diseases.

Spectrum of spontaneous mutation in animal cells containing an aphidicolin-resistant DNA polymerase alpha.

We have used a polymerase chain reaction (PCR)-based exon screening assay to determine the spectrum of spontaneous hypoxanthine phosphoribosyltransferase (hprt) gene mutations occurring in an aphidicolin-resistant V79 Chinese hamster cell line (designated Aphr-4-2) that contains a mutant DNA polymerase-alpha and displays a spontaneous mutator phenotype. PCR analyses of 71 independent, 6-thioguanine (TG)-resistant sublines isolated from Aphr-4-2 or parental V79-743X cells using hprt exon 3- and exon 9-specific oligonucleotide primer pairs revealed the loss of exon 3 or 9 from 6 of 60 Aphr-4-2 derived-, and from 1 of 11 parental V79-derived, TG-resistant mutants. Exons 3 and 9 were both lost from 5 of 60 Aphr-4-2-derived mutants, while none of the 11 V79-derived mutants had lost both exons. The results of these PCR-screening assays were further corroborated by Southern and Northern blot hybridization analyses of 28 mutants: 22 of 28 mutants contained an intact hprt gene by Southern analysis; of these 22 mutants 6 of 11 Aphr-4-2-derived mutants contained either reduced or undetectable steady state mRNA levels in contrast to all 11 V79-derived mutants that contained normal amounts of a normal-sized hprt mRNA. The results of our PCR and blot hybridization analyses indicate that the rates of base substitution and deletion mutagenesis are elevated in Aphr-4-2 cells, and suggest that DNA polymerase-alpha may play a role in determining the rate of different molecular types of spontaneous mutations in vivo.

Fluorescent in situ hybridization and cytogenetic studies of trisomy 12 in chronic lymphocytic leukemia.

Cytogenetic studies (CG) of 475 chronic lymphocytic leukemia (CLL) cases showed trisomy 12 in 6.1% or 26% of patients with abnormal karyotypes. Fluorescence in situ hybridization (FISH) detected trisomy 12 in 35% of 117 CLL patients. Only 34.6% of cases detected by FISH were detected by CG. Twelve patients had low levels of trisomic cells (4% to 11%) relative to clonal B cells (47.5% to 86%), suggestive of clonal evolution. Untreated patients with trisomy 12 were predominantly male (P < .05) and had an increased incidence of splenomegaly (P < .03). Patients with trisomy 12 were more likely to be previously treated and had advanced Binet stage compared with those without trisomy 12. The median survival was shorter in patients with trisomy 12 (7.8 years) and patients with other chromosomal abnormalities without trisomy 12 by FISH (5.5 years) than in patients with diploid karyotypes (14.4 years). The response to fludarabine was similar to that of patients with diploid karyotypes, but there was a trend for earlier disease progression. FISH detected residual disease in all patients with trisomy 12 in complete (n = 6) or partial remission (n = 4). As few as 1 trisomic cell in 5,000 was detected by performing FISH on fluorescence-activated cell sorter-sorted cells. Trisomy 12 was absent in T cells in patients with trisomy 12. We conclude that FISH identifies trisomy 12 approximately 2.6 times more often than CG, readily identifies minimal residual disease, and predicts for a shorter median survival.

Expression of AML1-ETO fusion transcripts and detection of minimal residual disease in t(8;21)-positive acute myeloid leukemia.

The t(8;21) translocation breakpoint, which is observed in acute myeloid leukemia (AML), has recently been cloned and a fusion transcript identified. We have now designed primer sets capable of amplifying the breakpoint junction of the fusion transcript by the reverse transcription-polymerase chain reaction (RT-PCR). Primer set 821U/821D1 amplified a 200-bp DNA fragment, and primer set 821U/821D2 amplified a 1.2-kb DNA fragment in all t(8;21)-positive AML tested. Sequence analysis of the amplified DNA fragments demonstrated that all fusion transcripts were fused at exactly the same site, indicating that this translocation breakpoint occurs within a single intron of the AML1 and ETO genes. Forty-five cycles of RT-PCR were used to detect residual t(8;21)-positive leukemia cells in three patients who had been in complete remission for 1, 3 and 5 years. Minimal residual disease was found in all three samples. Northern blot analysis demonstrated that two fusion transcripts of 7 and 10 kb were expressed in the t(8;21)-positive AML and that the ETO gene is not normally expressed in the hematopoietic system. Expression of a normal 5.5-kb ETO mRNA was found in the lung. From these results we concluded that expression of the ETO gene in t(8;21)-positive AML was activated as a result of the translocation.

Detection of residual proliferating leukemic cells by fluorescence in situ hybridization in CML patients in complete remission after interferon treatment.

Interferon-alpha produces a complete hematologic and cytogenetic remission in approximately 20% of patients with chronic myelogenous leukemia (CML). In this study, we applied fluorescent in situ hybridization (FISH) methodology to examine the possibility that a low level of proliferating Philadelphia-chromosome-positive (Ph+) cells may be present in interferon-treated CML patients who have achieved complete cytogenetic remission (as defined by the absence of Ph chromosome in 20-25 metaphases analyzed). Ten such patients in remission for 6-35 months were studied by this technique, in which a chromosome-22-specific DNA painting probe was used to detect leukemic cells with the characteristic 9;22 chromosomal translocation. In six of the 10 patients (60%), 3-9% Ph+ metaphases were detected. No Ph+ cells were observed in nine control individuals. Thus, this study demonstrates that FISH technology is more sensitive than conventional cytogenetic analysis for the detection of minimal residual disease in CML.

Distinct P-glycoprotein expression in two subclones simultaneously selected from a human colon carcinoma cell line by cis-diamminedichloroplatinum (II).

Two drug-resistant sublines, CP2.0 and RT, were simultaneously selected by cis-diamminedichloroplatinum (CDDP) from the human colon carcinoma cell line LoVo by the conventional method of continuous drug exposure. The 2 sublines differed in morphology, growth kinetics and pattern of gene expression. Genetic signature analysis indicated that the lines were independent subclones but that both arose from LoVo. These sublines were maintained in a growth medium containing 2.0 micrograms/ml CDDP. However, CP2.0 cells were 3 times more resistant to CDDP than were RT cells. Although both were cross-resistant to mustargen and 5-fluorouracil, only CP2.0 was resistant to Adriamycin and vincristine. Western-blot analysis, immunocytochemical staining and in vitro phosphorylation experiments indicated that the level of P-glycoprotein was significantly elevated in CP2.0 but not in RT. Despite the differences between these sublines, they possess similar CDDP-resistance mechanisms, including decreased intracellular CDDP accumulation, elevated levels of glutathione and metallothionein-like proteins, increased glutathione transferase-pi mRNA, and enhanced susceptibility to CDDP cytotoxicity after treatment with DL-buthionine-[S,R]-sulfoximine. Nevertheless, our results suggest that, in certain tumor types, P-glycoprotein-mediated multi-drug resistance and CDDP-resistance phenotypes can coexist in cells with primary resistance to CDDP.