Simultaneous isolation of hormone receptor-positive breast cancer organoids and fibroblasts reveals stroma-mediated resistance mechanisms

Recurrent hormone receptor-positive (HR+) breast cancer kills more than 600,000 women annually. Although HR+ breast cancers typically respond well to therapies, approximately 30% of patients relapse. At this stage, the tumors are usually metastatic and incurable. Resistance to therapy, particularly endocrine therapy is typically thought to be tumor intrinsic (e.g., estrogen receptor mutations). However, tumor-extrinsic factors also contribute to resistance. For example, stromal cells, such as cancer-associated fibroblasts (CAFs), residing in the tumor microenvironment, are known to stimulate resistance and disease recurrence. Recurrence in HR+ disease has been difficult to study due to the prolonged clinical course, complex nature of resistance, and lack of appropriate model systems. Existing HR+ models are limited to HR+ cell lines, a few HR+ organoid models, and xenograft models that all lack components of the human stroma. Therefore, there is an urgent need for more clinically relevant models to study the complex nature of recurrent HR+ breast cancer, and the factors contributing to treatment relapse. Here, we present an optimized protocol that allows a high take-rate, and simultaneous propagation of patient-derived organoids (PDOs) and matching CAFs, from primary and metastatic HR+ breast cancers. Our protocol allows for long-term culturing of HR+ PDOs that retain estrogen receptor expression and show responsiveness to hormone therapy. We further show the functional utility of this system by identifying CAF-secreted cytokines, such as growth-regulated oncogene α , as stroma-derived resistance drivers to endocrine therapy in HR+ PDOs.

The role of local radio in promoting creative engagement for healthy ageing

OBJECTIVES

To identify and critique literature on the links between public service local radio promoting creative engagement for healthy ageing in order to better understand the potential for public health agendas.

METHODS

This communication draws on preliminary learning from Up for Arts (UfA), a partnership initiative between BBC local radio and the UK charity Voluntary Arts. As part of the development of a logic model for the national roll-out of UfA, a scoping review of literature was undertaken. Eight search engines were searched systematically using four main search terms, 'older people', 'participatory arts', 'mass media' and 'public health'. Journals and websites were also opportunistically searched for outlying material. The inclusion criteria were qualitative, quantitative and mixed method studies and literature reviews published in English, between 2009 and 2018, wherein public service local radio was involved in promoting arts and crafts activities in local communities. Both formal activities, such as singing in a choir, and informal activities, such as a home-based knitting circle, were included. Art therapy, music therapy and other clinical interventions were excluded.

RESULTS

Of 708 papers, articles and reports identified through title, 37 were retained for primary screening. None met the criteria for inclusion. However, results on the individual search topics indicate that improved public health outcomes might result by including the promotion of creative engagement for healthy ageing.

CONCLUSION

Public Service Local Radio partnership initiatives, such as UfA, could have a role in supporting the development of creative engagement as a positive healthy ageing activity. This may be of interest and relevance to policymakers seeking novel ways to address health behaviours among people approaching old age.

Review of Antenatal-Linked Voluntary Counseling and HIV Testing in Sub-Saharan Africa: Lessons and Options for Ghana

SummaryVoluntary counselling and HIV testing has become an integral part of HIV prevention and care programs in many countries in sub-Saharan Africa. A number of interventions offer potential to reduce mother-to-child HIV transmission. These interventions, including antenatal and or intrapartum administration of antiretroviral drugs require the integration of voluntary counselling and HIV testing for pregnant women into antenatal care. Ghana's strategic framework for HIV control calls for the integration of voluntary counselling and HIV testing to antenatal care nationwide. It sets as target, the year 2005 when VCT would be widely available and accessible in the country. This paper reviews medline-indexed publications on antenatal-linked VCT programs of sub-Saharan Africa. Four critical themes were used in the medline search. These are acceptability, rates of return for test, disclosure of results vis-à-vis confidentiality and cost effectiveness. The growing consensuses on these issues are discussed in relations to the findings of a recent study conducted among 270 pregnant women in Navrongo in the Kassena-Nankana district of northern Ghana. Suggestions are made to guide the on-going pilot VCT and prevention of mother-to-child programs in Ghana. It is also suggested on the basis of the review and the findings of the Navrongo study that Ghana should explore options likely to promote universal access and overall acceptability. These include couple counselling, guarantee of confidentiality, free testing and continuum of care for mothers who are test positive.

The reactive transport of trichloroethene is influenced by residence time and microbial numbers

The dechlorination rate in a flow-through porous matrix can be described by the species specific dechlorination rate observed in a liquid batch unless mass transport limitations prevail. This hypothesis was examined by comparing dechlorination rates in liquid batch with that in column experiments at various flow rates (3-9-12 cm day(-1)). Columns were loaded with an inoculated sand and eluted with a medium containing 1mM trichloroethene (TCE) for 247 days. Dechlorination in the column treatments increased with decreasing flow rate, illustrating the effect of the longer residence time. Zeroth order TCE or cis-DCE degradation rates were 4-7 folds larger in columns than in corresponding batch systems which could be explained by the higher measured Geobacter and Dehalococcoides numbers per unit pore volume in the columns. The microbial numbers also explained the variability in dechlorination rate among flow rate treatments marked by a large elution of the dechlorinating species' yield as flow increased. Stop flow events did not reveal mass transport limitations for dechlorination. We conclude that flow rate effects on reactive transport of TCE in this coarse sand are explained by residence time and by microbial transport and that mass transport limitations in this porous matrix are limited.

Asynchronous non-invasive brain-actuated control of an intelligent wheelchair

In this paper we present further results of our asynchronous and non-invasive BMI for the continuous control of an intelligent wheelchair. Three subjects participated in two experiments where they steered the wheelchair spontaneously, without any external cue. To do so the users learn to voluntary modulate EEG oscillatory rhythms by executing three mental tasks (i.e., mental imagery) that are associated to different steering commands. Importantly, we implement shared control techniques between the BMI and the intelligent wheelchair to assist the subject in the driving task. The results show that the three subjects could achieve a significant level of mental control, even if far from optimal, to drive an intelligent wheelchair.

HRPT2 mutations are associated with malignancy in sporadic parathyroid tumours

BACKGROUND

Hyperparathyroidism is a common endocrinopathy characterised by the formation of parathyroid tumours. In this study, we determine the role of the recently identified gene, HRPT2, in parathyroid tumorigenesis.

METHODS

Mutation analysis of HRPT2 was undertaken in 60 parathyroid tumours: five HPT-JT, three FIHP, three MEN 1, one MEN 2A, 25 sporadic adenomas, 17 hyperplastic glands, two lithium associated tumours, and four sporadic carcinomas. Loss of heterozygosity at 1q24-32 was performed on a subset of these tumours.

RESULTS

HRPT2 somatic mutations were detected in four of four sporadic parathyroid carcinoma samples, and germline mutations were found in five of five HPT-JT parathyroid tumours (two families) and two parathyroid tumours from one FIHP family. One HPT-JT tumour with germline mutation also harboured a somatic mutation. In total, seven novel and one previously reported mutation were identified. "Two-hits" (double mutations or one mutation and loss of heterozygosity at 1q24-32) affecting HRPT2 were found in two sporadic carcinomas, two HPT-JT-related and two FIHP related tumours.

CONCLUSIONS

The results in this study support the role of HRPT2 as a tumour suppressor gene in sporadic parathyroid carcinoma, and provide further evidence for HRPT2 as the causative gene in HPT-JT, and a subset of FIHP. In light of the strong association between mutations of HRPT2 and sporadic parathyroid carcinoma demonstrated in this study, it is hypothesised that HRPT2 mutation is an early event that may lead to parathyroid malignancy and suggest intragenic mutation of HRPT2 as a marker of malignant potential in both familial and sporadic parathyroid tumours.

Genetic analysis of lithium-associated parathyroid tumors

OBJECTIVE

The aim of this study was to determine the primary genetic events that may underlie the formation of parathyroid tumors in patients with lithium-associated hyperparathyroidism (HPT).

METHODS

Comparative genomic hybridization (CGH), loss of heterozygosity (LOH) and multiple endocrine neoplasia type 1 gene (MEN1) mutation analysis were used to analyze twelve parathyroid tumors from nine patients with lithium-associated HPT. For comparison, CGH was also carried out in a non-lithium-associated group of thirteen sporadic parathyroid tumors.

RESULTS

A higher prevalence of multiglandular disease in the lithium-associated HPT patients compared with the idiopathic sporadic patients was observed (Fisher's exact test, P=0.02). CGH alterations were detected in four lithium-associated parathyroid tumors, involving loss at 1p, 11, 15q, 22q and gain of the X chromosome. In addition, one of these four cases exhibited LOH at 11q13 and was found to contain a novel somatic MEN1 mutation (c.1193insTAC). Although fewer lithium-associated parathyroid tumors were shown to contain genetic alterations compared with the sporadic parathyroid tumors, the changes detected were those frequently associated with both familial and sporadic parathyroid tumorigenesis.

CONCLUSION

This is, to our knowledge, the first genetic analysis of parathyroid tumors in lithium-associated HPT patients. Our data indicated that the majority of lithium-associated parathyroid tumors do not contain gross chromosomal alterations and suggest that in most cases the tumorigenic pathway is independent of MEN1 and genes at 1p34.3-pter and 1q21-q32. It is possible that other discrete genetic alterations or epigenetic changes, not screened for in this study, could also be responsible for parathyroid tumorigenesis in lithium-associated HPT.

Hemodynamic effects of levcromakalim in neonatal porcine pulmonary hypertension

Levcromakalim (LKM; a K(ATP) channel opener) reverses hypoxic pulmonary vasoconstriction in isolated pulmonary arteries and perfused lungs. This vasorelaxation is blocked by glibenclamide (GLB; a K(ATP) channel blocker). We evaluated the hemodynamic effect of LKM followed by GLB in a chronically instrumented neonatal porcine model of pulmonary hypertension, created by exposing piglets to hypoxia (n = 7) or heat-killed group B streptococci (GBS) (n = 6). Hypoxia increased pulmonary arterial pressure (PAP), which LKM decreased, and GLB subsequently increased in a dose-dependent manner. Systemic arterial pressure (SAP) did not change with hypoxia but was also decreased by LKM and increased by GLB. GBS also led to increased PAP, but LKM significantly reduced only SAP, which was then increased by GLB. We conclude LKM is capable of reversing hypoxic, but not GBS-induced, pulmonary hypertension but lacks specificity for the neonatal pulmonary vasculature.

Early expression of iepsilon, CD23 (FcepsilonRII), IL-4Ralpha, and IgE in the human fetus

BACKGROUND

A major predictor of childhood atopy is the concentration of IgE in the cord blood, but whether the source of cord blood IgE is maternal or fetal remains unclear.

OBJECTIVE

We sought to determine the pattern of in situ IgE production during ontogeny.

METHODS

Ninety-seven fetal, 142 natal, and 96 childhood samples were analyzed by using reverse transcription PCR for transcription of VDJCepsilon, Iepsilon, and CD23. Thirty-eight fetal liver samples were analyzed for the IL4RA genotype.

RESULTS

IL-4Ralpha, CD23a, CD23b, and sterile Iepsilon transcripts were present as early as 8 weeks' gestation. VDJCepsilon transcripts were found in second-trimester fetal liver and third-trimester cord blood, although they were rare. VDJCepsilon transcripts were more common in the blood of children 9 months and older. Sequence analysis suggested that fetal VDJCepsilon was the product of selection. All fetal livers actively transcribing Iepsilon, VDJCepsilon, and IL-4Ralpha contained at least one copy of the atopy-associated IL4RA*A1902G polymorphism.

CONCLUSION

The human fetus contains B cells that are primed to undergo IgE class switching from the earliest stages of ontogeny and can produce endogenous IgE by 20 weeks' gestation. However, IgE-producing cells are rare until 9 months after birth.

Broadsheet number 57: problems in fine needle biopsy of the thyroid

The role of fine needle biopsy and cytological diagnosis in the preoperative evaluation of thyroid nodules is reviewed on the basis of the current literature as well as the authors' personal experience. Technical aspects and guidelines for reporting thyroid samples are discussed in some detail. The main emphasis is on diagnostic pitfalls, those which may lead to a false-negative diagnosis, to a false-positive diagnosis or to an erroneous typing of the lesion, and their cytological patterns are described.

Loss of heterozygosity in sporadic parathyroid tumours: involvement of chromosome 1 and the MEN1 gene locus in 11q13

OBJECTIVE

Hyperparathyroidism (HPT) is a common endocrine disorder. Several loci of genetic interest have been identified in parathyroid tumours, including the MEN1 gene locus at 11q13; the HPT-JT region at 1q21-q32; and a putative tumour suppressor gene on 1p. We analysed these intervals, which harbour known genes or putative loci associated with familial hyperparathyroidism, in order to clarify the involvement of the respective regions in parathyroid tumourigenesis.

DESIGN

We performed loss of heterozygosity (LOH) studies on 33 sporadic parathyroid tumours using a PCR based technique. A total of 22 microsatellite markers were used to analyse loci at 11q13, 1q21-q32 and 1p. Ten markers located distal on 1p, eight markers encompassed the HPT-JT region at 1q21-q32 and four markers surrounded the MEN1 gene locus at 11q13. MEN1 mutations were screened for using Single Strand Conformation Polymorphism analysis (SSCP) and automated sequencing of SSCP variants.

PATIENTS

Thirty-three parathyroid glands and the corresponding blood samples were obtained from 33 patients (26 females and seven males) who underwent parathyroidectomy for primary hyperparathyroidism.

RESULTS

Loss of heterozygosity was detected in 13 of 33 (39%) cases at 11q13, 6 of 33 (18%) cases at 1p, and in three of 33 (9%) cases at 1q (in conjunction with 1p loss). Only one of the 18 tumours in which LOH was detected, showed LOH at both chromosome 1 and chromosome 11. Additionally, those tumours found to exhibit LOH at 11q13 were screened for MEN1 mutations using single strand conformation polymorphism analysis (SSCP) and automated sequencing. Nine novel somatic mutations were found on the remaining allele in 13 (69%) tumours.

CONCLUSIONS

This study consolidates the role of multiple loci in the pathogenesis of sporadic parathyroid tumours. The results indicate that there are at least two genetic loci involved in sporadic parathyroid tumourigenesis on chromosome 1, one of which has been linked to the distinct familial parathyroid condition, hyperparathyroidism-jaw tumour (HPT-JT) syndrome. The high frequency of loss of heterozygosity at 1p suggests the presence of a tumour suppressor at this locus.

Identification of Kel1p, a kelch domain-containing protein involved in cell fusion and morphology in Saccharomyces cerevisiae

We showed previously that protein kinase C, which is required to maintain cell integrity, negatively regulates cell fusion (Philips, J., and I. Herskowitz. 1997. J. Cell Biol. 138:961-974). To identify additional genes involved in cell fusion, we looked for genes whose overexpression relieved the defect caused by activated alleles of Pkc1p. This strategy led to the identification of a novel gene, KEL1, which encodes a protein composed of two domains, one containing six kelch repeats, a motif initially described in the Drosophila protein Kelch (Xue, F., and L. Cooley. 1993. Cell. 72:681- 693), and another domain predicted to form coiled coils. Overexpression of KEL1 also suppressed the defect in cell fusion of spa2Delta and fps1Delta mutants. KEL2, which corresponds to ORF YGR238c, encodes a protein highly similar to Kel1p. Its overexpression also suppressed the mating defect associated with activated Pkc1p. Mutants lacking KEL1 exhibited a moderate defect in cell fusion that was exacerbated by activated alleles of Pkc1p or loss of FUS1, FUS2, or FPS1, but not by loss of SPA2. kel1Delta mutants form cells that are elongated and heterogeneous in shape, indicating that Kel1p is also required for proper morphology during vegetative growth. In contrast, kel2Delta mutants were not impaired in cell fusion or morphology. Both Kel1p and Kel2p localized to the site where cell fusion occurs during mating and to regions of polarized growth during vegetative growth. Coimmunoprecipitation and two-hybrid analyses indicated that Kel1p and Kel2p physically interact. We conclude that Kel1p has a role in cell morphogenesis and cell fusion and may antagonize the Pkc1p pathway.

Incidence of free colorectal cancer cells on the peritoneal surface

BACKGROUND

The etiology and significance of port site recurrence occurring after laparoscopic-assisted resection for colorectal cancers will not be determined until controlled clinical trials determine if it is a predictor of outcome. Indirect evidence in support of transcoelomic spread of viable cancer cells to port sites during resection can be postulated by the presence of free cells on the fresh surface of colorectal specimens during primary resection.

PURPOSE

The study contained herein was undertaken to determine the incidence of free surface colorectal cancer cells by cytology during elective open resection and to correlate their presence with clinicopathologic variables.

METHODS

Fresh clamped and ligated consecutive colorectal cancer specimens were assessed in the operating room during primary resection for the presence of free colorectal cancer cells during an 18 month period at one institution. Clinicopathologic variables were assessed prospectively and blinded to cytology results. Interobserver reliability of cytologists was excellent (unweighted kappa, 0.93).

RESULTS

Overall, 15 of 103 (14.6 percent) colorectal cancers had positive cytology for cancer cells on the peritoneal or perirectal surface of the bowel. T3 and T4 tumors, the size or site of the tumor, lymph node status, mucinous characteristic, degree of differentiation, and the presence of vascular or neural invasion did not reach statistical significance as predictors of positive cytology in this study sample. The operative procedure performed was a statistically significant predictor of positive cytology. More than 50 percent of lymph nodes involved (28 percent), poorly differentiated tumors (28 percent), and the presence of liver metastases (22 percent) demonstrated a higher incidence of positive cytology, but this did not reach significant levels because of the limited power of the study sample for subgroup analysis.

DISCUSSION

The presence of free surface colorectal cancer cells gives only indirect support to the transcoelomic route to port site recurrence. The significance and true incidence will only be determined by prospective database analysis and randomized, controlled trials.

Stromal endometriosis of the cervix simulating Kaposi's sarcoma

Stromal endometriosis refers to the presence of endometriotic stroma without the presence of endometrial glands. We report a case in the uterine cervix in which the diagnosis of Kaposi's sarcoma was considered before being discounted on histological and immunohistochemical grounds.

Osmotic balance regulates cell fusion during mating in Saccharomyces cerevisiae

Successful zygote formation during yeast mating requires cell fusion of the two haploid mating partners. To ensure that cells do not lyse as they remodel their cell wall, the fusion event is both temporally and spatially regulated: the cell wall is degraded only after cell-cell contact and only in the region of cell-cell contact. To understand how cell fusion is regulated, we identified mutants defective in cell fusion based upon their defect in mating to a fus1 fus2 strain (Chenevert, J., N. Valtz, and I. Herskowitz. 1994. Genetics 136:1287-1297). Two of these cell fusion mutants are defective in the FPS1 gene, which codes for a glycerol facilitator (Luyten, K., J. Albertyn, W.F. Skibbe, B.A. Prior, J. Ramos, J.M. Thevelein, and S. Hohmann. 1995. EMBO [Eur. Mol. Biol. Organ.] J. 14:1360-1371). To determine whether inability to maintain osmotic balance accounts for the defect in cell fusion in these mutants, we analyzed the behavior of an fps1Delta mutant with reduced intracellular glycerol levels because of a defect in the glycerol-3-phosphate dehydrogenase (GPD1) gene (Albertyn, J., S. Hohmann, J.M. Thevelein, and B.A. Prior. 1994. Mol. Cell. Biol. 14:4135-4144): deletion of GPD1 partially suppressed the cell fusion defect of fps1 mutants. In contrast, overexpression of GPD1 exacerbated the defect. The fusion defect could also be partially suppressed by 1 M sorbitol. These observations indicate that the fusion defect of fps1 mutants results from inability to regulate osmotic balance and provide evidence that the osmotic state of the cell can regulate fusion. We have also observed that mutants expressing hyperactive protein kinase C exhibit a cell fusion defect similar to that of fps1 mutants. We propose that Pkc1p regulates cell fusion in response to osmotic disequilibrium. Unlike fps1 mutants, fus1 and fus2 mutants are not influenced by expression of GPD1 or by 1 M sorbitol. Their fusion defect is thus unlikely to result from altered osmotic balance.

Fine-needle aspiration biopsy of parotid lesions: comparison with frozen section

BACKGROUND

Opinions vary as to the necessity for fine-needle aspiration biopsy (FNAB) in parotid tumours. The present study reflects the experience gained over a 12-year period and shows the accuracy of a diagnostic FNAB, and improved results with experience.

METHODS

Between 1983 and 1995, 201 parotid lesions were excised by one surgeon(AGP) and a prospective database was established. Fine-needle aspiration biopsy was performed prior to surgery in 195 lesions and frozen section was performed in 159 lesions.

RESULTS

The FNAB was diagnostic in 129 (66%) specimens and its sensitivity for malignancy was 90% and specificity was 100% (excluding non-diagnostic FNAB, where there was insufficient cellular material for reliable diagnosis or where specific tissue diagnosis could not be given). The positive predictive value was 100% and the negative predictive value was 98%. Of interest, the positive predictive value of diagnostic FNAB for pleomorphic adenomas was 99%. A specific tumour diagnosis could not be made on the FNAB sample in 37 specimens; 11 of these lesions were histologically confirmed as malignant after excision. Frozen section was diagnostic in 144 specimens (91%). Its sensitivity for malignancy was 96% and specificity was 99%. The positive predictive value was 96% and negative predictive value 99%. A specific tumour diagnosis could not be made on frozen section in 15 specimens including six cases in which malignancy was finally reported. The positive predictive value of diagnostic frozen section for pleomorphic adenomas was 99%.

CONCLUSIONS

A diagnostic FNAB is an accurate and useful tool in the management of parotid lesions. An FNAB diagnosis of pleomorphic adenoma obviates the need for frozen section. The performance of FNAB in parotid tumours does not in any way preclude the necessity of surgical removal of such lesions except in exceptional circumstances.

Perturbation of nuclear architecture by long-distance chromosome interactions

SUMMARY

Position-effect variegation (PEV) describes the stochastic transcriptional silencing of a gene positioned adjacent to heterochromatin. Using FISH, we have tested whether variegated expression of the eye-color gene brown in Drosophila is influenced by its nuclear localization. In embryonic nuclei, a heterochromatic insertion at the brown locus is always spatially isolated from other heterochromatin. However, during larval development this insertion physically associates with other heterochromatic regions on the same chromosome in a stochastic manner. These observations indicate that the brown gene is silenced by specific contact with centromeric heterochromatin. Moreover, they provide direct evidence for long-range chromosome interactions and their impact on three-dimensional nuclear architecture, while providing a cohesive explanation for the phenomenon of PEV.

Correlation between cytopathological results and in situ hybridisation on needle aspiration biopsies of suspected African Burkitt's lymphomas

Burkitt's lymphoma (BL) is a very high-incidence malignancy in sub-Saharan Africa, where it targets mainly young children. This lymphoma is closely associated with Epstein-Barr virus (EBV). Diagnosis of BL relies on clinical presentation as well as histological results obtained from biopsies. In this report, 66 new patients from Malawi (one of the southernmost African countries with high-incidence BL), suspected on clinical grounds to present with BL, had fine needle aspiration biopsies taken, smeared on slides and used for May-Grünwald Giemsa staining. Duplicate slides were independently assessed for EBV presence and expression by DNA-DNA and/or RNA-RNA in situ hybridisation (ISH), using respectively the repetitive viral BamHIW DNA fragment in a biotinylated probe and the small EBV-encoded RNA EBER I in a digoxigenin-labelled riboprobe. There was very good correlation between the various techniques in the diagnosis of the lymphomas, showing 67% of clinically suspect cases to be BL. Our report, presenting data on BL in Malawi, illustrates the usefulness of a simple aspiration biopsy in the diagnosis of this malignancy by Giemsa staining and also in both types of ISH.

Characterization of a new human bladder cancer cell line, UCRU-BL-28

A new human bladder cancer cell line, UCRU-BL-28 has been established and characterized from a relapsed, cisplatin resistant, grade II, stage T4 tumor. This line is tumorigenic in nude mice and reflects the pathology of the original tumor. The morphology, the expression of tumor-associated antigens and EGF receptors, and the ability to grow both in an anchorage independent manner and in the absence of serum is explored. The BL-28 line has 71-74XXY chromosomes, with del 5q, der(9) and i(19q). Further studies on the molecular basis of bladder cancer, chemosensitivity to cisplatin, growth factor production and tissue invasion are under way.

Comparison of the expression of the seven ribosomal RNA operons in Escherichia coli

We have compared the expression of the seven ribosomal RNA operons (rrn) of Escherichia coli and their responses to a variety of physiological and genetic perturbations. We used a set of rrn promoter fusion constructs in their native chromosomal positions to examine effects of chromosomal location on rrn operon expression and the same set of fusions on lambda lysogens to assay intrinsic promoter strengths independent of chromosome context. In its native chromosomal location, expression of the rrnH operon was significantly lower than expected. This effect was not attributable to weak promoter activity and was dependent on the growth medium. The rrnE operon had reduced promoter activity relative to the other ribosomal operons in minimal medium and thus appears to have abnormal growth rate regulation. The ribosomal RNA operons showed varied responses to amino acid starvation; expression of rrnD was inhibited most. There was only a slight increase in rrn transcription in response to a temperature shift (30 degrees C to 42 degrees C) and the differences between individual operons was very small. The rrnG operon showed a significantly lower response than the other ribosomal RNA operons to a depletion of the rrn transcription activator, Fis, and thus appears to have decreased Fis-mediated transactivation. Finally, the chromosomal fusion strains were used to study the effect on growth rate of inactivating each rrn operon. In fast growth conditions, loss of certain rrn operons caused subtle decreases in growth rate on complex medium.

Antibiotic resistance of Escherichia coli in fecal samples of healthy people in two different areas in an industrialized country

Fecal samples of 310 healthy persons, from two populations from different areas in the Netherlands, were examined for the presence of Escherichia coli resistant to ampicillin, tetracycline, sulfamethoxazole, trimethoprim and nitrofurantoin. High prevalences of resistance were found in both populations, ranging from 28% for trimethoprim to 89% for ampicillin. The percentages of the fecal samples with a dominantly resistant E. coli flora (> 50% resistance) were distinctly lower, ranging from 1% for nitrofurantoin to 21% for tetracycline. No significant differences in the level of resistance were observed between these two comparable populations in two different areas. The susceptibilities to 11 antimicrobial agents of 456 at random isolated E. coli were determined. The percentages of resistance varied widely: from 80% for chloramphenicol to 9% for nitrofurantoin. Only 19% of the isolates were susceptible to all antibiotics tested and 14% were resistant to more than four of the agents tested. Great differences in resistance rates between the two populations examined were seen for chloramphenicol (80% to 41%) and trimethoprim (16% to 36%). The results of this study underscore the presence of a human reservoir of antibiotic resistant microorganisms.

Prognostic significance of nuclear DNA content in phaeochromocytoma

Nuclear DNA content of 27 phaeochromocytomas was measured by image analysis of thin sections and monolayer smears of nuclei extracted from thick sections (cytospins) using archival paraffin-embedded tissue blocks. Recurrence was assessed on the basis of clinical follow-up or urinary catecholamine levels. The mean follow-up was 5.0 years, with a range of 4 months to 15 years. Although it is not possible to differentiate accurately malignant tumours using DNA analysis, prediction of benign tumours is possible. Using thin sections, all tumours were benign when the percentage of cells with a DNA content of 2.5 c (2 c = diploid) was less than 40% and the DNA content of 5 c was less than 4%. Using the cytospin preparation, all diploid tumours were benign. Thus, patients with diploid tumours may be saved intensive long-term follow-up. Aneuploid and tetraploid tumours, however, continue to require careful lifelong follow-up.

Growth and metastasis of human bladder cancer xenografts in the bladder of nude rats. A model for intravesical radioimmunotherapy

A potentially useful therapeutic approach to the treatment of human bladder cancer is intravesical therapy with radiolabelled monoclonal antibodies (MAbs). We have established an animal model to study this approach. Inoculation of cloned 2B8 cells derived from the human bladder cancer cell line, UCRU-BL-17, into the bladder wall of nude rats pre-irradiated with 900 rads, resulted in local tumour growth in 39/40 (97.5%) animals, with invasion or metastases to distant organs in 25% of cases. Both the bladder tumours and the metastases were morphologically similar to the original biopsy sample from which the cell line, UCRU-BL-17, was established. The cells were of human origin, as shown by expression of HLA antigens, Alu probing, and cytogenetic analysis. Preliminary studies indicated that i.p. injection of anti-human bladder cancer monoclonal antibody (MAb), BLCA-38, radiolabelled with either iodine 131 or samarium 153 (153Sm), resulted in tumour localisation, with tumour-to-blood ratios of 5.04 (131I), and 4.3 and 3.1 (153Sm) respectively. We now aim to examine the efficacy of the intravesical route for radioimmunotherapy in the nude rat model. This model will also serve for preclinical studies on the efficacy of systemically injected radioimmunoconjugates for control of metastatic growth.

Comparison of image analysis and flow cytometric determination of cellular DNA content

A good correlation (r = 0.94) was obtained between the DNA indices (DI) using flow cytometry and image analysis of nuclei cytospins extracted from paraffin wax embedded tumour sections. Some of the limitations and problems associated with image analysis which came to light included an unacceptably high coefficient of variation (CV) and a "left-shift" in the DI in most DNA histograms obtained when using image analysis of 5 microns sections. In contrast, the DNA histograms generated using image analysis of cytospun nuclei from paraffin wax blocks were of good quality and similar to those obtained using flow cytometry. Variability in Feulgen staining was common and an important source of error despite rigorous control of the staining technique. This could be overcome by using internal controls such as fibroblasts rather than external controls (rat hepatocytes) to determine the diploid DI with image analysis. A thorough understanding and appreciation of the methodological problems associated with image analysis and flow cytometric determination of DNA content is required before these methods find widespread clinical application.

High prevalence of antibiotic resistant Escherichia coli in faecal samples of students in the south-east of The Netherlands

From December 1988 to March 1989 172 faecal samples from first and second year students at the University of Limburg, Maastricht, The Netherlands, were collected and analysed for the presence of Escherichia coli strains resistant to ampicillin, sulphamethoxazole, tetracycline, trimethoprim and nitrofurantoin. In addition, the antibiotic susceptibility (MIC) to these agents and six other compounds (i.e. aminoglycosides, nitrofurantoin, nalidixic acid and cephalothin) was determined. The prevalence of resistance of the samples analysed ranged from 86% (i.e. 148 out of 172) for sulphamethoxazole to 25% for trimethoprim. The prevalence figures for ampicillin, tetracycline and nitrofurantoin resistance were 76%, 47% and 29%, respectively. The percentages of the faecal samples with a high proportion of E. coli (greater than 50% of the total number of E. coli) resistant to ampicillin, tetracycline and sulphamethoxazole were 8%, 11% and 37%, respectively. For nitrofurantoin and trimethoprim the figures were 3% and 1%, respectively. Of the isolated E. coli (n = 797), 84% was resistant to ampicillin, 82% resistant to sulphamethoxazole. The lowest percentages (9%) were observed for both nalidixic acid and nitrofurantoin.

Routine use of intraoperative epicardial echocardiography and Doppler color flow imaging to guide and evaluate repair of congenital heart lesions. A prospective study

Routine epicardial two-dimensional echocardiography, Doppler, and Doppler color flow imaging studies were performed before and after cardiopulmonary bypass in 328 patients undergoing operations for congenital heart disease. Ages ranged from 1 day to 59 years (mean 5.9 years); the smallest patient was 1.8 kg. Complete examinations were conducted in 3.6 +/- 1.7 minutes. Prebypass examinations demonstrated previously unappreciated details of anatomy in 60 patients (18%), which did not relate to whether catheterization had been performed, and they were believed to play a role in surgical planning in 143 patients (44%). Discovery of previously unrecognized features of anatomy increased the impact of echo-Doppler color flow imaging on operative planning by 2.5 times. After bypass, echo-Doppler color flow imaging disclosed unsuspected residual defects in 22 patients (7%) who were doing well clinically and enabled an attempt at immediate revision of the procedure. When ultimate clinical outcome was compared to postbypass findings of echo-Doppler color flow imaging, the presence of a residual defect, right or left ventricular dysfunction, or any concern with the heart by echo-Doppler color flow imaging appeared to serve as a predictor of unfavorable outcome (p less than 0.001 for each when compared with absence of these difficulties). Thus routine intraoperative echo-Doppler color flow imaging is useful in aiding the planning, conduct, and assessment of results in operations for congenital heart disease.

Clonal analysis of a bladder cancer cell line: an experimental model of tumour heterogeneity

The continuous cell line UCRU BL 17CL was derived from a human invasive bladder cancer and expresses elements of transitional, squamous and glandular differentiation. Nine clones of this line were established by limit dilution and have been extensively characterised. Only six of these clones grew subcutaneously in nude mice. Of these, three have exhibited local invasion, each in one of five implanted mice. Although all xenografts expressed transitional, squamous and glandular elements, different histological subtypes predominated within each clone. Only clones which grew in nude mice formed colonies in semi-solid medium, and each responded differently to the influence of medium that had been conditioned by the growth of UCRU BL 17CL, suggesting the possible secretion of a growth factor by these cells. The DNA content and lectin binding profiles of the clones also reflected the heterogeneity of the line. UCRU BL 17CL and the nine clones provide a unique model for the study of tumour heterogeneity, progression and differentiation, and the potential autocrine regulation of growth of bladder cancer.

Detection of malignant cells in voided urine from patients with bladder cancer, a novel monoclonal assay

A simple assay is described for detecting malignant cells in the voided urine from patients with transitional cell carcinoma of the bladder. Agarose-embedded urothelial cells from 24 biopsy-proven cancer patients and 10 controls were stained for surface immunofluorescence with four monoclonal antibodies reactive with human bladder cancer and three monoclonals reactive with blood group A. Reactivity was assessed by fluorescence microscopy. One antibody, BLCA-8 appeared to have particular diagnostic utility. Thus, 24.3 +/- 5.8 percent of outer layer and 27.0 +/- 4.6 percent of inner layer urothelial cells reacted with BLCA-8 in patient samples, compared to 2.9 +/- 1.0 and 0.8 +/- 0.5 percent of similar cells from control urines. BLCA-8 antigen expression was found to be relatively stable even after prolonged exposure to urine. In a comparison with conventional cytology, samples from 4/8 patients were considered positive by standard methods, whereas, 8/8 were BLCA-8 positive. This new technique may thus be a useful adjunct to conventional methods.

Characterization of cell lines derived from a multiply aneuploid human bladder transitional-cell carcinoma, UCRU-BL-13

A series of cultured cell lines (designated UCRU-BL-13) has been established from different serial passages of a multiply aneuploid human bladder transitional-cell carcinoma xenografted in nude mice. Serial passage of the xenografts in vivo and of the cell lines in vitro was accompanied by shifts in the tumor ploidy, with dominance of different major peaks. Despite this, the expression of tumor markers remained constant, and consistent chromosomal markers were observed both in the 8th xenograft passage and in a subline in tissue culture established over a year apart. Chromosomal numbers reflected the predominant aneuploid peaks observed; consistent numerical and structural changes included a marker derived from chromosome 1, 8p-, -10, 11q+, and 17q+. The cell line derived from the initial xenograft comprised a mixture of transitional, adenocarcinoma and squamous carcinoma cells in early passage, but adenocarcinoma cells were absent from later passages. The lines expressed the B-blood-group antigen, histocompatibility antigens, receptors for transferrin and EGF, and reacted with a series of monoclonal antibodies (MAbs) directed to malignant human epithelial cell lines. These lines provide a model for studying the evolution of tumor heterogeneity and drug resistance in bladder carcinoma exhibiting multiple aneuploidy.

The stability and short-term fluctuation in serum oxytocinase activity in pregnancy

Maternal serum samples obtained from 123 normal pregnant women between 28 and 40 weeks gestation were analysed for oxytocinase (EC 3.4.11.3) activity using s-benzyl-1-cysteine-4-nitroanilide as substrate. Oxytocinase activity was found to be stable at varying temperatures, with a mean co-efficient of variation of 5.0%. The short-term fluctuation of oxytocinase activity had a mean coefficient of variation of 3.6%. There is no suggestion of a "pulsatile" release of oxytocinae from its placental origin.