An experimental framework to assess biomolecular condensates in bacteria

High-resolution imaging of biomolecular condensates in living cells is essential for correlating their properties to those observed through in vitro assays. However, such experiments are limited in bacteria due to resolution limitations. Here we present an experimental framework that probes the formation, reversibility, and dynamics of condensate-forming proteins in Escherichia coli as a means to determine the nature of biomolecular condensates in bacteria. We demonstrate that condensates form after passing a threshold concentration, maintain a soluble fraction, dissolve upon shifts in temperature and concentration, and exhibit dynamics consistent with internal rearrangement and exchange between condensed and soluble fractions. We also discover that an established marker for insoluble protein aggregates, IbpA, has different colocalization patterns with bacterial condensates and aggregates, demonstrating its potential applicability as a reporter to differentiate the two in vivo. Overall, this framework provides a generalizable, accessible, and rigorous set of experiments to probe the nature of biomolecular condensates on the sub-micron scale in bacterial cells.

Dissecting the phase separation and oligomerization activities of the carboxysome positioning protein McdB

Across bacteria, protein-based organelles called bacterial microcompartments (BMCs) encapsulate key enzymes to regulate their activities. The model BMC is the carboxysome that encapsulates enzymes for CO2 fixation to increase efficiency and is found in many autotrophic bacteria, such as cyanobacteria. Despite their importance in the global carbon cycle, little is known about how carboxysomes are spatially regulated. We recently identified the two-factor system required for the maintenance of carboxysome distribution (McdAB). McdA drives the equal spacing of carboxysomes via interactions with McdB, which associates with carboxysomes. McdA is a ParA/MinD ATPase, a protein family well studied in positioning diverse cellular structures in bacteria. However, the adaptor proteins like McdB that connect these ATPases to their cargos are extremely diverse. In fact, McdB represents a completely unstudied class of proteins. Despite the diversity, many adaptor proteins undergo phase separation, but functional roles remain unclear. Here, we define the domain architecture of McdB from the model cyanobacterium Synechococcus elongatus PCC 7942, and dissect its mode of biomolecular condensate formation. We identify an N-terminal intrinsically disordered region (IDR) that modulates condensate solubility, a central coiled-coil dimerizing domain that drives condensate formation, and a C-terminal domain that trimerizes McdB dimers and provides increased valency for condensate formation. We then identify critical basic residues in the IDR, which we mutate to glutamines to solubilize condensates. Finally, we find that a condensate-defective mutant of McdB has altered association with carboxysomes and influences carboxysome enzyme content. The results have broad implications for understanding spatial organization of BMCs and the molecular grammar of protein condensates.

An experimental framework to assess biomolecular condensates in bacteria

High-resolution imaging of biomolecular condensates in living cells is essential for correlating their properties to those observed through in vitro assays. However, such experiments are limited in bacteria due to resolution limitations. Here we present an experimental framework that probes the formation, reversibility, and dynamics of condensate-forming proteins in Escherichia coli as a means to determine the nature of biomolecular condensates in bacteria. We demonstrate that condensates form after passing a threshold concentration, maintain a soluble fraction, dissolve upon shifts in temperature and concentration, and exhibit dynamics consistent with internal rearrangement and exchange between condensed and soluble fractions. We also discovered that an established marker for insoluble protein aggregates, IbpA, has different colocalization patterns with bacterial condensates and aggregates, demonstrating its applicability as a reporter to differentiate the two in vivo. Overall, this framework provides a generalizable, accessible, and rigorous set of experiments to probe the nature of biomolecular condensates on the sub-micron scale in bacterial cells.

An experimental framework to assess biomolecular condensates in bacteria

High-resolution imaging of biomolecular condensates in living cells is essential for correlating their properties to those observed through in vitro assays. However, such experiments are limited in bacteria due to resolution limitations. Here we present an experimental framework that probes the formation, reversibility, and dynamics of condensate-forming proteins in Escherichia coli as a means to determine the nature of biomolecular condensates in bacteria. We demonstrate that condensates form after passing a threshold concentration, maintain a soluble fraction, dissolve upon shifts in temperature and concentration, and exhibit dynamics consistent with internal rearrangement and exchange between condensed and soluble fractions. We also discovered that an established marker for insoluble protein aggregates, IbpA, has different colocalization patterns with bacterial condensates and aggregates, demonstrating its applicability as a reporter to differentiate the two in vivo. Overall, this framework provides a generalizable, accessible, and rigorous set of experiments to probe the nature of biomolecular condensates on the sub-micron scale in bacterial cells.

PRI: Re-Analysis of a Public Mass Cytometry Dataset Reveals Patterns of Effective Tumor Treatments

Recently, mass cytometry has enabled quantification of up to 50 parameters for millions of cells per sample. It remains a challenge to analyze such high-dimensional data to exploit the richness of the inherent information, even though many valuable new analysis tools have already been developed. We propose a novel algorithm “pattern recognition of immune cells (PRI)” to tackle these high-dimensional protein combinations in the data. PRI is a tool for the analysis and visualization of cytometry data based on a three or more-parametric binning approach, feature engineering of bin properties of multivariate cell data, and a pseudo-multiparametric visualization. Using a publicly available mass cytometry dataset, we proved that reproducible feature engineering and intuitive understanding of the generated bin plots are helpful hallmarks for re-analysis with PRI. In the CD4⁺T cell population analyzed, PRI revealed two bin-plot patterns (CD90/CD44/CD86 and CD90/CD44/CD27) and 20 bin plot features for threshold-independent classification of mice concerning ineffective and effective tumor treatment. In addition, PRI mapped cell subsets regarding co-expression of the proliferation marker Ki67 with two major transcription factors and further delineated a specific Th1 cell subset. All these results demonstrate the added insights that can be obtained using the non-cluster-based tool PRI for re-analyses of high-dimensional cytometric data.

Dissection of the ATPase active site of McdA reveals the sequential steps essential for carboxysome distribution

Carboxysomes, the most prevalent and well-studied anabolic bacterial microcompartment, play a central role in efficient carbon fixation by cyanobacteria and proteobacteria. In previous studies, we identified the two-component system called McdAB that spatially distributes carboxysomes across the bacterial nucleoid. Maintenance of carboxysome distribution protein A (McdA), a partition protein A (ParA)-like ATPase, forms a dynamic oscillating gradient on the nucleoid in response to the carboxysome-localized Maintenance of carboxysome distribution protein B (McdB). As McdB stimulates McdA ATPase activity, McdA is removed from the nucleoid in the vicinity of carboxysomes, propelling these proteinaceous cargos toward regions of highest McdA concentration via a Brownian-ratchet mechanism. How the ATPase cycle of McdA governs its in vivo dynamics and carboxysome positioning remains unresolved. Here, by strategically introducing amino acid substitutions in the ATP-binding region of McdA, we sequentially trap McdA at specific steps in its ATP cycle. We map out critical events in the ATPase cycle of McdA that allows the protein to bind ATP, dimerize, change its conformation into a DNA-binding state, interact with McdB-bound carboxysomes, hydrolyze ATP, and release from the nucleoid. We also find that McdA is a member of a previously unstudied subset of ParA family ATPases, harboring unique interactions with ATP and the nucleoid for trafficking their cognate intracellular cargos.

Carboxysome Mispositioning Alters Growth, Morphology, and Rubisco Level of the Cyanobacterium Synechococcus elongatus PCC 7942

Cyanobacteria are the prokaryotic group of phytoplankton responsible for a significant fraction of global CO2 fixation. Like plants, cyanobacteria use the enzyme ribulose 1,5-bisphosphate carboxylase/oxidase (Rubisco) to fix CO2 into organic carbon molecules via the Calvin-Benson-Bassham cycle. Unlike plants, cyanobacteria evolved a carbon-concentrating organelle called the carboxysome-a proteinaceous compartment that encapsulates and concentrates Rubisco along with its CO2 substrate. In the rod-shaped cyanobacterium Synechococcus elongatus PCC 7942, we recently identified the McdAB system responsible for uniformly distributing carboxysomes along the cell length. It remains unknown what role carboxysome positioning plays with respect to cellular physiology. Here, we show that a failure to distribute carboxysomes leads to slower cell growth, cell elongation, asymmetric cell division, and elevated levels of cellular Rubisco. Unexpectedly, we also report that even wild-type S. elongatus undergoes cell elongation and asymmetric cell division when grown at the cool, but environmentally relevant, growth temperature of 20°C or when switched from a high- to ambient-CO2 environment. The findings suggest that carboxysome positioning by the McdAB system functions to maintain the carbon fixation efficiency of Rubisco by preventing carboxysome aggregation, which is particularly important under growth conditions where rod-shaped cyanobacteria adopt a filamentous morphology. IMPORTANCE Photosynthetic cyanobacteria are responsible for almost half of global CO2 fixation. Due to eutrophication, rising temperatures, and increasing atmospheric CO2 concentrations, cyanobacteria have gained notoriety for their ability to form massive blooms in both freshwater and marine ecosystems across the globe. Like plants, cyanobacteria use the most abundant enzyme on Earth, Rubisco, to provide the sole source of organic carbon required for its photosynthetic growth. Unlike plants, cyanobacteria have evolved a carbon-concentrating organelle called the carboxysome that encapsulates and concentrates Rubisco with its CO2 substrate to significantly increase carbon fixation efficiency and cell growth. We recently identified the positioning system that distributes carboxysomes in cyanobacteria. However, the physiological consequence of carboxysome mispositioning in the absence of this distribution system remains unknown. Here, we find that carboxysome mispositioning triggers changes in cell growth and morphology as well as elevated levels of cellular Rubisco.

Identification of a super-functional Tfh-like subpopulation in murine lupus by pattern perception

Dysregulated cytokine expression by T cells plays a pivotal role in the pathogenesis of autoimmune diseases. However, the identification of the corresponding pathogenic subpopulations is a challenge, since a distinction between physiological variation and a new quality in the expression of protein markers requires combinatorial evaluation. Here, we were able to identify a super-functional follicular helper T cell (Tfh)-like subpopulation in lupus-prone NZBxW mice with our binning approach "pattern recognition of immune cells (PRI)". PRI uncovered a subpopulation of IL-21⁺ IFN-γ^high PD-1^low CD40L^high CXCR5^- Bcl-6^- T cells specifically expanded in diseased mice. In addition, these cells express high levels of TNF-α and IL-2, and provide B cell help for IgG production in an IL-21 and CD40L dependent manner. This super-functional T cell subset might be a superior driver of autoimmune processes due to a polyfunctional and high cytokine expression combined with Tfh-like properties.

Health-Related Quality of Life Among Vietnamese Breast Cancer Women

The aim of the study was to investigate health-related quality of life among Vietnamese breast cancer women who were treated at National Cancer Hospital, Hanoi, Vietnam, in 2018. Information about physical functioning, Role Physical, Bodily Pain, General Health, vitality, Social Functioning, Role Emotional, and Mental Health of 200 patients with breast cancer was collected through face-to-face interview, using short form-36 questionnaire. We found that the older patients (older than 50 years) had higher score of Mental Health than patients at age 50 and lower (P < .05). The patients who had better economic status had significantly higher score of Vitality (P < .05). Patients who were married and living with their partners/husband had better quality of life in General Health (P<0.05). The patients who had less than 6 months of treatment had better physical functioning score (P < .05) than the patients who had treatment longer than 6 months. Patients with caring supports from family members had higher scores of Bodily Pain, Social Functioning, Role Emotional, and Mental Health. Patients who have stressed feelings had significantly lower scores of all domains, except for Physical Functioning. The participants who usually stay up late reported lower scores of all components except for Physical Functioning and Role Physical. In conclusion, it is needed to develop psychosocial services, enhance early screening, and diagnose for the women in Vietnam.

Ultrasensitive Response of Developing Myxococcus xanthus to the Addition of Nutrient Medium Correlates with the Level of MrpC

Upon depletion of nutrients, Myxococcus xanthus forms mounds on a solid surface. The differentiation of rod-shaped cells into stress-resistant spores within mounds creates mature fruiting bodies. The developmental process can be perturbed by the addition of nutrient medium before the critical period of commitment to spore formation. The response was investigated by adding a 2-fold dilution series of nutrient medium to starving cells. An ultrasensitive response was observed, as indicated by a steep increase in the spore number after the addition of 12.5% versus 25% nutrient medium. The level of MrpC, which is a key transcription factor in the gene regulatory network, correlated with the spore number after nutrient medium addition. The MrpC level decreased markedly by 3 h after adding nutrient medium but recovered more after the addition of 12.5% than after 25% nutrient medium addition. The difference in MrpC levels was greatest midway during the period of commitment to sporulation, and mound formation was restored after 12.5% nutrient medium addition but not after adding 25% nutrient medium. Although the number of spores formed after 12.5% nutrient medium addition was almost normal, the transcript levels of "late" genes in the regulatory network failed to rise normally during the commitment period. However, at later times, expression from a reporter gene fused to a late promoter was higher after adding 12.5% than after adding 25% nutrient medium, consistent with the spore numbers. The results suggest that a threshold level of MrpC must be achieved in order for mounds to persist and for cells within to differentiate into spores.IMPORTANCE Many signaling and gene regulatory networks convert graded stimuli into all-or-none switch-like responses. Such ultrasensitivity can produce bistability in cell populations, leading to different cell fates and enhancing survival. We discovered an ultrasensitive response of M. xanthus to nutrient medium addition during development. A small change in nutrient medium concentration caused a profound change in the developmental process. The level of the transcription factor MrpC correlated with multicellular mound formation and differentiation into spores. A threshold level of MrpC is proposed to be necessary to initiate mound formation and create a positive feedback loop that may explain the ultrasensitive response. Understanding how this biological switch operates will provide a paradigm for the broadly important topic of cellular behavior in microbial communities.

Targeted or whole genome sequencing of formalin fixed tissue samples: potential applications in cancer genomics

Current genomic studies are limited by the poor availability of fresh-frozen tissue samples. Although formalin-fixed diagnostic samples are in abundance, they are seldom used in current genomic studies because of the concern of formalin-fixation artifacts. Better characterization of these artifacts will allow the use of archived clinical specimens in translational and clinical research studies. To provide a systematic analysis of formalin-fixation artifacts on Illumina sequencing, we generated 26 DNA sequencing data sets from 13 pairs of matched formalin-fixed paraffin-embedded (FFPE) and fresh-frozen (FF) tissue samples. The results indicate high rate of concordant calls between matched FF/FFPE pairs at reference and variant positions in three commonly used sequencing approaches (whole genome, whole exome, and targeted exon sequencing). Global mismatch rates and C·G > T·A substitutions were comparable between matched FF/FFPE samples, and discordant rates were low (<0.26%) in all samples. Finally, low-pass whole genome sequencing produces similar pattern of copy number alterations between FF/FFPE pairs. The results from our studies suggest the potential use of diagnostic FFPE samples for cancer genomic studies to characterize and catalog variations in cancer genomes.

Somatic loss of function mutations in neurofibromin 1 and MYC associated factor X genes identified by exome-wide sequencing in a wild-type GIST case

Background

Approximately 10–15 % of gastrointestinal stromal tumors (GISTs) lack gain of function mutations in the KIT and platelet-derived growth factor receptor alpha (PDGFRA) genes. An alternate mechanism of oncogenesis through loss of function of the succinate-dehydrogenase (SDH) enzyme complex has been identified for a subset of these “wild type” GISTs.

Methods

Paired tumor and normal DNA from an SDH-intact wild-type GIST case was subjected to whole exome sequencing to identify the pathogenic mechanism(s) in this tumor. Selected findings were further investigated in panels of GIST tumors through Sanger DNA sequencing, quantitative real-time PCR, and immunohistochemical approaches.

Results

A hemizygous frameshift mutation (p.His2261Leufs*4), in the neurofibromin 1 (NF1) gene was identified in the patient’s GIST; however, no germline NF1 mutation was found. A somatic frameshift mutation (p.Lys54Argfs*31) in the MYC associated factor X (MAX) gene was also identified. Immunohistochemical analysis for MAX on a large panel of GISTs identified loss of MAX expression in the MAX-mutated GIST and in a subset of mainly KIT-mutated tumors.

Conclusion

This study suggests that inactivating NF1 mutations outside the context of neurofibromatosis may be the oncogenic mechanism for a subset of sporadic GIST. In addition, loss of function mutation of the MAX gene was identified for the first time in GIST, and a broader role for MAX in GIST progression was suggested.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1872-y) contains supplementary material, which is available to authorized users.

Abstract 4281: Targeted or whole genome sequencing of formalin-fixed tissue samples

Background: To provide a systematic analysis of formalin fixation artifacts on Illumina sequencing libraries and results, we generated two complementary sequencing libraries (target enrichment sequencing and whole exome sequencing) from 11 pairs of matched formalin-fixed paraffin-embedded (FFPE) and fresh-frozen (FF) tumor samples and two pairs of matched FFPE and FF germline samples. We also generated whole genome sequencing data from a single pair of FF/FFPE tumor samples.

Results: The results indicate minimal variations in library fragment size, coverage, and PCR duplicates within FF/FFPE paired samples that are less than 1 year old; whereas, a large variation in these parameters were observed in FF/FFPE pairs in samples that are approximately 2 years old. No significant increase in global mismatch rates and C•G&gt;T•A substitutions were observed in FFPE samples from the former group; whereas, a discernible increase in mismatch rates and C•G&gt;T•A substitutions were observed in FFPE samples from the latter group. However, over 99.7% and 99.5% of concordant calls were observed between matched FF and FFPE pairs at reference and non-reference positions within the targeted regions, respectively. Although an increased rate of global mismatches and C•G&gt;T•A substitutions were observed in some FFPE samples, discordant rates were low (&lt;0.26) in all samples because most of the FFPE artifacts were filtered out using GATK workflow. Consistent with this analysis, C•G&gt;T•A substitutions are comparable in non-reference positions in paired FF and FFPE samples.

Conclusions: We developed upfront quality assessment and library preparation method that use low input DNA from FFPE samples to perform next-generation sequencing. The results from our studies indicate the suitability of FFPE samples in sequencing studies.

Citation Format: Sarah Munchel, Yen Hoang, Yue Zhao, Joseph Cottrell, Brandy Klotzle, Andrew Godwin, Janelle Noel, Brooke Fridley, Peter Beyerlein, Jian-Bing Fan, Marina Bibikova, Jeremy R. Chien. Targeted or whole genome sequencing of formalin-fixed tissue samples. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4281. doi:10.1158/1538-7445.AM2014-4281

Abstract 2008: Genomic medicine using NexGen sequencing to personalized treatment of metastatic adenoid cystic carcinoma (ADCC)

Background:

ADCC is a form of cancer usually originating from saliva gland. The standard treatment is surgical resection followed by adjuvant radiation if indicated. Cases of metastatic disease can behave indolently but ultimately can be fatal and there is no effective therapy. We present the results of NexGen sequencing of a 41yo caucasian female diagnosed with ADCC in 2003 who subsequently developed recurrence in 2005 and pulmonary metastases in 2006. She was treated with multiple agents including radiation. She had further progression with increase dyspnea in 2012. Commercial profiling by Caris Biosciences found expression of VEGFR, PDGFRA and PDGFRB. She was treated with Sorafenib, an oral multikinase inhibitor of the VEGFR, PDGFR, and BRAF without improvement, and she developed further dyspnea requiring oxygen. We performed NexGen sequencing of a biopsied metastatic lesion to identify somatic mutations and to determine if any targeted agent would be of further benefit. Results: NextGen sequencing was performed on DNA extracted from formalin-fixed tumor biopsy sample. Blood DNA served as control. Using Illumina TruSeq Exome Enrichment kit, 100 bp paired-end sequencing was performed on the tumor and normal exomes. Resulting sequences were mapped to the Human Reference Genome (hg19) using two bioinformatics workflows: CLC Genomics Workbench and BWA/GATK. Single nucleotide variants (SNVs) and small insertions/deletions (INDELs) were separately characterized for normal and tumor exomes. Finally, germline variants (SNVs and INDELs) were subtracted to identify putative somatic mutations in tumor exome. Concensus somatic mutations were obtained from CLC and BWA/GATK workflows. A total of 569 non-synonymous mutations and 35 stopgain mutations were observed in the tumor exome. Mutations in BRCA2, IGF1R, KDR, MTOR, TP63, XPC, RAD17, MLH1, and PTEN were observed in the tumor exome. Mutations in the components of kinase-mediated signaling (IGF1R, KDR, MTOR, PTEN) are potential targets of kinase and mTOR inhibitors whereas mutations in the DNA repair pathways (TP63, XPC, RAD17, MLH1) may be targeted with DNA alkylating agents. The result indicates that patient's tumor harbor several mutations that can be targeted by available cancer drugs. Conclusions: We found several mutated molecular pathways that can be targeted with available agents using exome sequencing. Improvement in outcome could validate the role of exome sequencing in treatment selection of advanced cancers without standard therapy.

Citation Format: Chao H. Huang, Yen Hoang, Kay Minn, Andrew Godwin, Jeremy Chien. Genomic medicine using NexGen sequencing to personalized treatment of metastatic adenoid cystic carcinoma (ADCC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2008. doi:10.1158/1538-7445.AM2013-2008

Spontaneous ovarian hyperstimulation in a naturally conceived pregnancy with uncontrolled hypothyroidism

BACKGROUND

Spontaneous ovarian hyperstimulation syndrome is a rare occurrence in pregnancy. This is a case of pregnancy with spontaneous ovarian hyperstimulation syndrome, uncontrolled hypothyroidism, elevated human chorionic gonadotropin (hCG), deep vein thrombosis, and Rh isoimmunization.

CASE

An African-American woman in her mid-30s, gravida 3 para 0, with hypothyroidism presented with abdominal pain, hCG 291,206 milli-International Units/mL, thyroid stimulating hormone 41.7 milliunits/L, hematocrit 12.8%, and Anti-D titer 1:256. Pelvic ultrasonography revealed a pregnancy at 10 weeks of gestation with enlarged adnexal masses. Doppler images demonstrated a right, lower extremity, deep vein thrombosis. Conservative maternal treatment involved levothyroxine and heparin with regression of the ovaries by 22 weeks of gestation after adequate thyroid repletion. Fetal surveillance was with serial ultrasound examinations of the estimated fetal weight, amniotic fluid index, and the fetal middle cerebral artery Doppler images. Cesarean delivery of a nonhydropic 1,400-gram newborn occurred at 35 weeks of gestation. Although born prematurely, the newborn required only 2 liters of oxygen through nasal cannula initially, received only 2 blood transfusions, advanced to oral feeds quickly, had good urine output throughout the hospitalization, and had a normal hearing examination upon discharge. The bilirubin levels remained stable with some phototherapy, so exchange transfusion was not necessary.

CONCLUSION

Spontaneous ovarian hyperstimulation syndrome can occur in pregnant women with severe hypothyroidism or extremely elevated hCG and present with enlarged adnexal masses and acute abdominal pain. Accurate diagnosis and continuation of pregnancy with conservative management is a viable option, once ovarian malignancy is ruled out.

Coexisting ovarian malignancy in young women with endometrial cancer

OBJECTIVE

In premenopausal women with endometrial cancer, ovarian preservation may be a consideration. Our objective was to examine the occurrence of coexisting ovarian malignancy and to identify predictors of adnexal involvement.

METHODS

With institutional review board approval, a retrospective chart review was conducted of young women with endometrial cancer identified at 4 affiliated institutions from 1996 to 2004.

RESULTS

Among 102 young women (aged 24-45 years) who underwent hysterectomy for endometrial cancer, 26 (25%) were found to have coexisting epithelial ovarian tumors: 23 were classified as synchronous primaries, and 3 as metastases. Ovarian cancer histology was endometrioid in 92% of cases. Among the 26 cases of coexisting ovarian involvement, 12 (46%) had grade 1 endometrial cancer on preoperative biopsy, 4 (15%) had normal preoperative imaging of the adnexa, and 4 (15%) had benign-appearing ovaries at the time of intraoperative assessment. On final pathology, 18 of 26 cases (69%) occurred in patients with grade 1 endometrial cancers, and 15 (58%) occurred with inner myometrial invasion. Our study further highlights the risk of conservative management with 1 case of ovarian cancer diagnosed 9 months after hysterectomy with ovarian conservation for a stage IA, grade 1 endometrial cancer and a case of advanced endometrial cancer metastatic to the ovaries developing 3 years after successful resolution of a grade 1 endometrial cancer treated with megestrol acetate (Megace).

CONCLUSION

Careful preoperative and intraoperative assessment of the adnexa is mandatory in young women with endometrial cancer. Those who desire ovarian preservation should be counseled regarding the high rate of coexisting ovarian malignancy.

Altered patterns of migration of cytokine-producing T lymphocytes in skin-grafted naive or immune mice following in vivo administration of anti-VCAM-1 or -ICAM-1

Naive or preimmunized (to B10.BR or BALB.k) C3H/HeJ mice received skin grafts from multiple minor histoincompatible B10.BR or BALB.k mice following antigen-specific portal venous (p.v.) pretransplant transfusion, a protocol known to produce prolongation of graft survival in naive animals. In addition, groups of mice received intravenous (i.v.) infusion following transplantation with a mixture of monoclonal antibodies (mAb) to vascular adhesion molecule-1L: very late activation antigen-4 (VCAM-1:VLA-4) or intracellular adhesion molecule-1:lymphocyte function-associated antigen-3 (ICAM-1:LFA-1). Cells were harvested from different tissues of the grafted mice at various times post grafting. RNA was extracted and analysed, using polymerase chain reaction, for expression of different cytokines potentially involved in the regulation of graft rejection [interleukin-2 (IL-2), IL-4, IL-6, IL-10, tumour necrosis factor-alpha, interferon-gamma and transforming growth factor-beta]. In addition, using limiting dilution analysis, we investigated the frequency of allo-specific and third-party reactive cells producing IL-2 and IL-4 in vitro in different tissues of grafted mice following these treatments. The mAb treatment protocol which produced optimum increases in graft survival in naive versus immune mice was different, with anti-LFA-1:ICAM-1 superior for naive mice compared with anti-VLA-4:VCAM-1, and vice versa for immune animals. However, in each case, increased survival was associated with increases local to the graft in the frequency of occurrence of antigen-specific type-2 cytokine-producing cells.

A subset of gamma delta T-cell receptor-positive cells produce T-helper type-2 cytokines and regulate mouse skin graft rejection following portal venous pretransplant preimmunization

C3H/HeJ mice received B10.BR skin grafts following portal or lateral tail vein infusion of irradiated B10.BR spleen cells. Thereafter mice were injected with anti-alpha beta or anti-gamma delta T-cell receptor (TCR) monoclonal antibody (mAb). Anti-gamma delta TCR mAb abolished the increased graft survival afforded by portal venous (p.v.) immunization, and reversed the bias towards expression of mRNA for type-2 cytokines [interleukin-4 (IL-4), IL-10] seen in lymphoid tissue of p.v.-immunized mice. When gamma delta TCR+ and alpha beta TCR+ cells were isolated from the intestinal epithelial compartment (IEL), liver or Peyer's Patch (PP) of p.v.-immunized mice, the gamma delta TCR+ cells were found to be enriched in cells producing type-2 cytokines on rechallenge with irradiated B10.BR cells in vitro. gamma delta TCR+ cells from p.v.-immunized mice were further expanded in vitro with anti-CD3 and cytokines (combined IL-2 and IL-4). Following expansion these cells were capable of adoptively transferring increased B10.BR skin graft survival to naive mice, and continued to show a bias in type-2 cytokine synthesis after allostimulation in vitro. When gamma delta TCR chain expression was assessed in cells taken from p.v.-immunized mice, or in cells expanded in culture, our data suggest that p.v. immunization leads to oligoclonal, not polyclonal, expansion of those gamma delta TCR+ cells involved in inhibition of graft rejection.

Protection by milk immunoglobulin concentrate against oral challenge with enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli is a common cause of traveler's diarrhea. Prophylaxis against traveler's diarrhea has been associated with side effects from bismuth subsalicylate and the development of resistance to antimicrobial agents. We undertook a double-blind controlled trial in which a bovine milk immunoglobulin concentrate with high titers of antibodies against enterotoxigenic E. coli was used as prophylaxis against E. coli challenge in volunteers. Lyophilized milk immunoglobulins were prepared from the colostrum of cows immunized with several enterotoxigenic E. coli serotypes and fimbria types, E. coli heat-labile enterotoxin, and cholera toxin. As a control, an immunoglobulin concentrate with no anti-E. coli activity was prepared. Ten volunteers received buffered immunoglobulin concentrate against enterotoxigenic E. coli, and 10 received the control immunoglobulin concentrate, dissolved in water, three times a day. No side effects were observed. On the third day of immunoglobulin prophylaxis, the volunteers were given 10(9) colony-forming units of enterotoxigenic E. coli H10407 (O78:H11). This strain produces colonization factor antigen I and heat-labile and heat-stable enterotoxins. None of the 10 volunteers receiving the immunoglobulin concentrate against E. coli had diarrhea, but 9 of the 10 controls did (P less than 0.0001). All volunteers excreted E. coli H10407. We conclude from these preliminary results that milk immunoglobulin concentrate may be an effective prophylaxis against traveler's diarrhea.