Nucleolus activity-dependent recruitment and biomolecular condensation by pH sensing

DEAD-box ATPases are major regulators of biomolecular condensates and orchestrate diverse biochemical processes that are critical for the functioning of cells. How DEAD-box proteins are selectively recruited to their respective biomolecular condensates is unknown. We explored this in the context of the nucleolus and DEAD-box protein DDX21. We find that the pH of the nucleolus is intricately linked to the transcriptional activity of the organelle and facilitates the recruitment and condensation of DDX21. We identify an evolutionarily conserved feature of the C terminus of DDX21 responsible for nucleolar localization. This domain is essential for zebrafish development, and its intrinsically disordered and isoelectric properties are necessary and sufficient for the ability of DDX21 to respond to changes in pH and form condensates. Molecularly, the enzymatic activities of poly(ADP-ribose) polymerases contribute to maintaining the nucleolar pH and, consequently, DDX21 recruitment and nucleolar partitioning. These observations reveal an activity-dependent physicochemical mechanism for the selective recruitment of biochemical activities to biomolecular condensates.

SBDSR126T rescues survival of sbds -/- zebrafish in a dose-dependent manner independently of Tp53

Defects in ribosomal biogenesis profoundly affect organismal development and cellular function, and these ribosomopathies produce a variety of phenotypes. One ribosomopathy, Shwachman-Diamond syndrome (SDS) is characterized by neutropenia, pancreatic exocrine insufficiency, and skeletal anomalies. SDS results from biallelic mutations in SBDS, which encodes a ribosome assembly factor. Some individuals express a missense mutation, SBDS R126T , along with the common K62X mutation. We reported that the sbds-null zebrafish phenocopies much of SDS. We further showed activation of Tp53-dependent pathways before the fish died during the larval stage. Here, we expressed SBDS R126T as a transgene in the sbds -/- background. We showed that one copy of the SBDS R126T transgene permitted the establishment of maternal zygotic sbds-null fish which produced defective embryos with cdkn1a up-regulation, a Tp53 target involved in cell cycle arrest. None survived beyond 3 dpf. However, two copies of the transgene resulted in normal development and lifespan. Surprisingly, neutropenia persisted. The surviving fish displayed suppression of female sex differentiation, a stress response in zebrafish. To evaluate the role of Tp53 in the pathogenesis of sbds -/- fish phenotype, we bred the fish with a DNA binding deficient allele, tp53 M214K Expression of the loss-of-function tp53 M214K did not rescue neutropenia or survival in sbds-null zebrafish. Increased expression of cdkn1a was abrogated in the tp53 M214K/M214K ;sbds -/- fish. We conclude that the amount of SBDSR126T protein is important for development, inactivation of Tp53 fails to rescue neutropenia or survival in the sbds-null background, and cdkn1a up-regulation was dependent on WT tp53 We hypothesize that additional pathways are involved in the pathophysiology of SDS.

Impact of surgical left atrial appendage closure during coronary bypass on clinical outcomes and readmissions

Background

Whether surgical left atrial appendage closure (sLAAC) during coronary artery bypass (CABG)surgery improves post-operative outcome including stroke and atrial fibrillation (AF) occurrence is largely unknown.

Objective

To analyze the impact of concomitant sLAAC during CABG in terms of outcomes and readmissions over the following year.

Methods

We analyzed the Nationwide Readmissions Database (2016–2019) using ICD-10 codes to identify hospitalizations for CABG. Patients were subcategorized based on whether sLAAC was performed or not. Among patients who survived their index admission, we employed propensity matching (1:3) to adjust for age, sex, comorbidities, CHA2DS2-VASc scores, previous AF history, heart failure and hospital characteristics. Primary outcomes included unplanned AF and stroke-related readmissions at 1 year.

Results

A total of 58,311 patients with CABG and sLAAC were identified with 175,940 propensity matched controls. Patients undergoing sLAAC were older with higher CHA2DS2-VASc scores and comorbidity burdens. Confounders were well balanced following propensity matching. Over a mean follow-up of 152 days, sLAAC was associated with higher risk of readmission due to AF at one year (HR 1.71 [1.49–1.96] p<0.001). This association is independent of previous AF history. Lower rates of stroke-related readmission was associated with perfomance of sLAAC (HR 0.80 (0.65–0.97) p=0.026), however the association was not observed when accounting for AF history.

Conclusion

CABG with concomitant sLAAC is maybe associated with lower stroke risk at the cost of higher risk of AF readmissions.

Funding Acknowledgement

Type of funding sources: None.

Calmodulin inhibitors improve erythropoiesis in Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a rare hematopoietic disease characterized by a block in red cell differentiation. Most DBA cases are caused by mutations in ribosomal proteins and characterized by higher than normal activity of the tumor suppressor p53. Higher p53 activity is thought to contribute to DBA phenotypes by inducing apoptosis during red blood cell differentiation. Currently, there are few therapies available for patients with DBA. We performed a chemical screen using zebrafish ribosomal small subunit protein 29 (rps29) mutant embryos that have a p53-dependent anemia and identified calmodulin inhibitors that rescued the phenotype. Our studies demonstrated that calmodulin inhibitors attenuated p53 protein amount and activity. Treatment with calmodulin inhibitors led to decreased p53 translation and accumulation but does not affect p53 stability. A U.S. Food and Drug Administration-approved calmodulin inhibitor, trifluoperazine, rescued hematopoietic phenotypes of DBA models in vivo in zebrafish and mouse models. In addition, trifluoperazine rescued these phenotypes in human CD34⁺ hematopoietic stem and progenitor cells. Erythroid differentiation was also improved in CD34⁺ cells isolated from a patient with DBA. This work uncovers a potential avenue of therapeutic development for patients with DBA.

Loss of Sbds in zebrafish leads to neutropenia and pancreas and liver atrophy

Shwachman-Diamond syndrome (SDS) is characterized by exocrine pancreatic insufficiency, neutropenia, and skeletal abnormalities. Biallelic mutations in SBDS, which encodes a ribosome maturation factor, are found in 90% of SDS cases. Sbds^–/– mice are embryonic lethal. Using CRISPR/Cas9 editing, we created sbds-deficient zebrafish strains. Sbds protein levels progressively decreased and became undetectable at 10 days postfertilization (dpf). Polysome analysis revealed decreased 80S ribosomes. Homozygous mutant fish developed normally until 15 dpf. Mutant fish subsequently had stunted growth and showed signs of atrophy in pancreas, liver, and intestine. In addition, neutropenia occurred by 5 dpf. Upregulation of tp53 mRNA did not occur until 10 dpf, and inhibition of proliferation correlated with death by 21 dpf. Transcriptome analysis showed tp53 activation through upregulation of genes involved in cell cycle arrest, cdkn1a and ccng1, and apoptosis, puma and mdm2. However, elimination of Tp53 function did not prevent lethality. Because of growth retardation and atrophy of intestinal epithelia, we studied the effects of starvation on WT fish. Starved WT fish showed intestinal atrophy, zymogen granule loss, and tp53 upregulation — similar to the mutant phenotype. In addition, there was reduction in neutral lipid storage and ribosomal protein amount, similar to the mutant phenotype. Thus, loss of Sbds in zebrafish phenocopies much of the human disease and is associated with growth arrest and tissue atrophy, particularly of the gastrointestinal system, at the larval stage. A variety of stress responses, some associated with Tp53, contribute to pathophysiology of SDS.

Loss of ribosome maturation factor sbds in the zebrafish phenocopies human Shwachman-Diamond syndrome and is associated with p53 activation, but lethality cannot be rescued by p53 mutation.

Abstract P3-01-08: HER2-negative metastatic breast cancer with HER2-positive circulating tumor cells (CTCs): A new CTC-defined HER2-positive subgroup

Introduction: CTCs can overexpress HER2 discordant from tumor HER2 expression. We aimed to describe characteristics of a CTC-defined group of pts with metastatic breast cancer (MBC) that is tumor HER2- and CTC HER2+ (HER2 tumor- CTC+).

Methods: We retrospectively analyzed data from pts treated at Northwestern University who had serial evaluation of CTCs and circulating tumor DNA (ctDNA). We included pts with pathologically confirmed HER2- MBC and HER2+ CTCs. CTCs were enumerated with the CellSearch immunomagnetic kit (Menarini Silicon Biosystems), HER2 expression on CTCs was determined using the CellSearch CXC Kit in 7.5 cc whole blood, and ctDNA was analyzed using the Guardant360 NGS assay (Guardant Health).

Results: Among 98 pts with HER2- MBC and CTC analysis, 46 (47%) had at least 1 HER2+ CTC. In this cohort the median age was 53. At initial BC diagnosis, 80% had early stage or locally advanced BC and 20% had de-novo metastatic disease. Baseline histology was 65% ductal, 20% lobular, 2% mixed ductal and lobular, and 13% unknown. Pathology of metastatic tumor was hormone receptor positive (HR+)/HER2- in 78% and triple negative in 22%. Detailed HER2 immunohistochemistry (IHC) and FISH results from metastases were available from 63% of pts of whom 72% had an IHC score of 0 or 1 and 28% had an IHC score of 2 with negative FISH testing. The median time from the most recent pathologic metastatic tumor assessment to the detection of a HER2+ CTC was 6.5 mo. Twenty-two pts had simultaneous (within 8 weeks) HER2- tumor confirmation and HER2+ CTC detection. The median lines of endocrine therapy (ET) for MBC prior to detection of HER2+ CTCs was 1 (range 0-5, 41% no ET, 17% 1 line, 41% >2 lines). Pts received a median of 2 (range 0-10) prior systemic therapies for MBC prior to detection of HER2+ CTCs, (20% 0 lines, 41% 1-3 lines, and 39% >4 lines). Among these 46 pts, CTCs were analyzed longitudinally in 104 samples, with HER2+ CTCs detected in 77 samples. Number of HER2+ CTCs at initial detection ranged from <5 in 24%, 5-50 in 43%, and >50 in 33%, with a median of 11.5 HER2+ CTCs. CTC clusters were noted in 37% of pts. At initial detection the proportion of CTCs that were HER2+ was 0-25% in 13% of pts, 26-50% in 46% of pts, and 51-100% in 41% of pts. Seven pts had ERBB2 aberrations in ctDNA. Of 12 pts with tumor sequencing, 2 had ERBB2 mutations, 1 had ERBB3 amplification, and 1 had overexpression of ERBB3 RNA. After detection of HER2+ CTCs, 18 pts received HER2 directed therapy (with chemotherapy in 13 pts, with endocrine therapy in 4 pts, and as monotherapy in 1 pt). Imaging demonstrated a partial response or stable disease in 9 pts (clinical benefit rate 50%), including in 1 pt with trastuzumab monotherapy, progressive disease in 8 pts, and not evaluated in 1 pt.

Conclusions: HER2+ CTCs are frequently detected simultaneously or soon after HER2- tumor assessment in MBC. Within this newly defined subgroup, the several responses seen with HER2 targeted therapy serve as a proof of concept that HER2 tumor- CTC+ patients can benefit from HER2 targeted therapy. Future studies are needed to determine a clinically relevant threshold for HER2+ CTCs to guide further study of HER2 therapy combinations in HER2 tumor- CTC+ pts.

Citation Format: Shah AN, Gerratana L, Zhang Q, Davis AA, Zhang Y, Flaum L, Behdad A, Platanias L, Gradishar WJ, Cristofanilli M. HER2-negative metastatic breast cancer with HER2-positive circulating tumor cells (CTCs): A new CTC-defined HER2-positive subgroup [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-01-08.

Abstract P1-16-08: Response to subsequent therapy after dual immune checkpoint blockade in metastatic breast cancer

Introduction: While initial studies have found that combining chemotherapy with immune checkpoint blockade (ICB) can augment responses, additional toxicity has been observed. The optimal sequencing of chemotherapy and ICB has not yet been described. Sequential responses to chemotherapy after ICB have been reported in various tumor types; however, data is limited, and this has not been described in breast cancer to date.

Methods: We identified patients (pts) from a small pilot study in HER2-negative metastatic breast cancer (MBC) who received at least 1 cycle of durvalumab (PD-L1 inhibitor) and tremelimumab (CTLA-4 inhibitor). We excluded pts without follow up data or if they did not receive subsequent systemic therapy. Comparison of differences between subgroups was calculated by Fisher's exact test for categorical variables and Wilcoxon rank-sum test for continuous variables. Time to treatment failure (TTF) of subsequent therapy and overall survival (OS) were assessed by the Kaplan-Meier method and differences between breast cancer subtype were compared by log-rank tests.

Results: Twenty-three pts received at least 1 cycle of ICB of whom 14 pts were eligible for this analysis. Nine had estrogen receptor positive (ER+) BC and 5 had triple negative (TN) BC. There were no statistically significant differences between the ER+ and TN subgroups in age, race, ethnicity, ECOG performance status (PS) at end of ICB, or sites of metastatic disease except for more lymph node metastases in the TN cohort (p=0.003). Overall response rates to ICB in this cohort was higher in TN vs ER+ (40% vs 0%, p=0.11). Pts received a median of 4 lines of systemic therapy for MBC prior to ICB. Subsequent therapy after ICB was eribulin in 29%, carboplatin/gemcitabine in 21%, palbociclib + endocrine therapy (ET) in 14%, anthracycline in 14%, ixabepilone +/- capecitabine in 14%, and paclitaxel in 7%. Clinical response was seen in 8 pts (57%), of whom 5 had ER+ BC and 3 had TNBC. The median TTF of subsequent therapy was 3.0 mo (1.9, 5.5), which compared to a median TTF for therapy prior to ICB of 2.5 mo. The median OS was 12.3 mo (2.3-13.3). There were no significant differences between the ER+ and TN cohorts (log-rank test p=0.74 and 0.90 for TTF and OS, respectively. Subsequent therapy was discontinued due to progressive disease in 44%, decline in PS in 19%, liver failure in 6%, treatment related adverse event in 6%, and unknown cause in 13%. Two pts remain on subsequent therapy with palbociclib + ET beyond 6 mo without disease progression. There were no statistically significant differences between TTF >3 mo (n=5) and TTF <3 mo (n=9) subgroups. Pts with TTF >3 mo were numerically more likely to have a PS 0-1 (100 vs 78%), liver metastases (80 vs 56%), and ER+ BC (80 vs 56%). Pts with TTF <3 mo had more lymphopenia (66% vs 20%) and more lines of prior systemic therapy for MBC (median 6 vs 4).

Conclusions: While median duration of response on subsequent therapy was short, a subset of pts had significant clinical responses. These findings provide rationale for prospective validation as they provide strategies for sequencing ICB with standard therapies.

Citation Format: Shah AN, Yalamanchili A, Helenowski I, Bhole S, Woodman J, Gradishar WJ, Cristofanilli M, Santa-Maria CA. Response to subsequent therapy after dual immune checkpoint blockade in metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-08.

Abstract P3-01-19: HER2-positive circulating tumor cells (CTCs) in advanced breast cancer (BC): A feature independent of BC subtype

Introduction: HER2 overexpression is observed on CTCs in advanced BC (ABC), but their significance is not known. We aimed to describe clinical, pathologic, and molecular associations with HER2 overexpression on CTCs in ABC patients (pts).

Methods: We conducted a retrospective analysis of data from ABC pts treated at Thomas Jefferson University and Northwestern University who had evaluation of CTCs and circulating tumor DNA (ctDNA). CTCs were enumerated with the CellSearch immunomagnetic kit (Menarini Silicon Biosystems), HER2 expression on CTCs was evaluated using the CellSearch CXC Kit, and ctDNA was analyzed using the Guardant360 NGS assay (Guardant Health). Associations with the presence of HER2+ CTCs were explored through univariate and multivariate logistic regression. Kruskal-Wallis testing evaluating HER2+ CTCs as a continuous variable was also conducted to confirm consistency of findings. Time to development of HER2+ CTCs was evaluated using Cox proportional hazards regression analysis.

Results: Baseline CTCs were evaluated in 209 pts (10% stage III, 90% stage IV) of whom 41% had no detectable CTCs, 23% had 1-4 CTCs, and 36% had >5 CTCs (stage IV aggressive). Twelve percent had CTC clusters. At least 1 HER2+ CTC was seen in 33% of pts at baseline draw. Of 39 patients with HER2+ BC, only 18% had HER2+ CTCs. Of patients with HER2+ CTCs, 55% had hormone receptor positive BC, 28% had triple negative BC, and 18% had HER2+ BC. On univariate logistic analysis, BC subtype or HER2 status was not associated with the presence of HER2+ CTCs. IBC pts represented 52% of pts and were less likely to have HER2+ CTCs (OR 0.40 95% CI 0.19-0.84). Bone metastases were associated with an increased likelihood of HER2+ CTCs (OR 2.46, 95% CI 1.12-5.38); however, other sites of metastases and number of metastatic sites were not correlated with HER2+ CTCs. Aggressive disease features including >5 CTCs and presence of CTC clusters were strongly associated with HER2+ CTCs (OR 15.72, 95% CI 6.89-35.8 and 8.97, 95% CI 3.23-24.89, respectively). Of 168 pts with ctDNA analysis, ERRB2 aberrations were seen in 22% of pts and were significantly associated with HER2+ CTCs (OR of 3.74, 95% CI 1.45-9.63). On multivariate analysis, the associations with >5 CTCs and ERBB2 alterations in ctDNA remained statistically significant. The associations of HER2+ CTCs with bone disease, >5 CTCs, CTC clusters, and ERBB2 alterations in ctDNA, and the inverse relationship with IBC were consistent when HER2+ CTCs were evaluated as a continuous variable with Kruskal-Wallis testing. Among pts without HER2+ CTCs at baseline, the time to detection of HER2+ CTCs correlated with the presence of bone metastases (HR 3.40, 95% CI 1.14-10.19), >5 CTCs (3.77, 95% CI 1.33-10.70), and visceral disease (HR 3.00, 95% CI 1.07-8.44).

Conclusions: HER2+ CTCs are common in ABC, independent of HER2 status of the tumor, and, in fact, common in the luminal BC. HER2+ CTCs were also strongly associated with CTC characteristics of aggressive disease with poor survival (CTCs clusters and >5 CTCs) and ERBB2 aberrations in ctDNA. Further studies will be investigating the role of HER2+ CTCs in endocrine resistance and the potential of anti-HER2 therapy in this unique CTC-defined setting.

Citation Format: Shah AN, Gerratana L, Davis AA, Zhang Q, Zhang Y, Rossi G, Wang C, Strickland K, Yang H, Flaum L, Abu-Khalaf M, Behdad A, Ye Z, Platanias L, Gradishar WJ, Cristofanilli M. HER2-positive circulating tumor cells (CTCs) in advanced breast cancer (BC): A feature independent of BC subtype [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-01-19.

Tuberculosis infection control measures at health care facilities offering HIV and tuberculosis services in India: A baseline assessment

BACKGROUND

Tuberculosis (TB) is one of world's oldest infectious disease and ranks alongside HIV as leading infectious killer. Tuberculosis infection control especially in HIV and TB care facilities has warranted attention after the recent health care-associated outbreaks in South Africa. The aim of this study was to describe the tuberculosis infection control measures implemented by HIV and TB care facilities in five high HIV burden provinces in India.

METHODS

Baseline assessment of 30 high burden Antiretroviral centers and TB facilities was conducted during Oct 2015-Dec 2015 by AIC trained staff using a structured format.

RESULTS

Thirty HIV and TB care facilities in five high HIV burden provinces were enrolled. Facility infrastructure and airborne infection control practices were highly varied between facilities. TB screening and fast tracking at ART centers is happening at majority of centers however inadequate TB infection control training, poor compliance to administrative and personal protective measures and lack of mechanism for health care workers surveillance need attention.

CONCLUSIONS

Local specific TB infection control interventions to be designed and implemented at HIV and TB care facilities including implementation of administrative, environmental and use of personal protective equipment's with the training of staff members. Health care workers surveillance needs to be prioritized considering the rising instances of tuberculosis among Health care workers.

Macrophage-Dependent Cytoplasmic Transfer during Melanoma Invasion In Vivo

Interactions between tumor cells and tumor-associated macrophages play critical roles in the initiation of tumor cell motility. To capture the cellular interactions of the tumor microenvironment with high-resolution imaging, we directly visualized tumor cells and their interactions with macrophages in zebrafish. Live imaging in zebrafish revealed that macrophages are dynamic, yet maintain sustained contact with tumor cells. In addition, the recruitment of macrophages to tumor cells promotes tumor cell dissemination. Using a Cre/LoxP strategy, we found that macrophages transfer cytoplasm to tumor cells in zebrafish and mouse models. Remarkably, macrophage cytoplasmic transfer correlated with melanoma cell dissemination. We further found that macrophages transfer cytoplasm to tumor cells upon cell contact in vitro. Thus, we present a model in which macrophage/tumor cell contact allows for the transfer of cytoplasmic molecules from macrophages to tumor cells corresponding to increased tumor cell motility and dissemination.

Why are HIV-infected people not started on antiretroviral therapy? A mixed-methods study from Gujarat, India

Setting: Five purposively selected antiretroviral therapy (ART) centres in Gujarat, India. Objectives: To assess the proportion of ART-eligible people living with the human immunodeficiency virus (PLHIV) who were not initiated on ART within 2 months of being recorded as eligible, to identify factors associated with non-initiation and to explore reasons from the provider's perspective. Design: We used a mixed-methods design (triangulation) of 1) a quantitative phase involving record reviews and cohort analysis (Poisson regression) of PLHIV registered during April 2014-March 2015, and 2) a qualitative phase involving one-to-one interviews with 25 providers. Results: Of 2079 ART-eligible PLHIV, 339 (16%) were not started on ART within 2 months. PLHIV with CD4 counts of <350 cells/μl and patients who were labourers, hospitalised, bedridden or registered with certain ART centres were more likely not to be initiated on ART. Qualitative results were categorised into two broad themes: government health system- and patient-related challenges, which validated and complemented the quantitative findings. Conclusion: Several patient subgroups at greater risk of ART non-initiation were identified, along with reasons for risk; this has important programme implications for achieving the UNAIDS 90-90-90 goal, and particularly the second 90 component of having 90% of diagnosed PLHIV start ART.

A genetic basis for molecular asymmetry at vertebrate electrical synapses

Neural network function is based upon the patterns and types of connections made between neurons. Neuronal synapses are adhesions specialized for communication and they come in two types, chemical and electrical. Communication at chemical synapses occurs via neurotransmitter release whereas electrical synapses utilize gap junctions for direct ionic and metabolic coupling. Electrical synapses are often viewed as symmetrical structures, with the same components making both sides of the gap junction. By contrast, we show that a broad set of electrical synapses in zebrafish, Danio rerio, require two gap-junction-forming Connexins for formation and function. We find that one Connexin functions presynaptically while the other functions postsynaptically in forming the channels. We also show that these synapses are required for the speed and coordination of escape responses. Our data identify a genetic basis for molecular asymmetry at vertebrate electrical synapses and show they are required for appropriate behavioral performance.

DOI:http://dx.doi.org/10.7554/eLife.25364.001

Are partners of HIV-infected people being tested for HIV? A mixed-methods research from Gujarat, India

Setting: Four selected antiretroviral therapy (ART) centres of Gujarat State, India, which accounts for 8% of the human immunodeficiency virus (HIV) burden in India. Objectives: 1) To assess the proportion of people living with HIV (PLHIV) whose partners were not tested for HIV; 2) to assess sociodemographic and clinical characteristics of index cases associated with partner testing; and 3) to understand perceived facilitators and barriers to partner testing and make suggestions on how to improve testing from the perspective of the health-care provider. Design: A mixed-method design with a quantitative phase that involved reviewing the programme records of married PLHIV enrolled during 2011-2015, followed by a qualitative phase of key informant interviews. Results: Of 3884 married PLHIV, 1279 (33%) did not have their partners tested for HIV. Factors including index cases being male, illiterate, aged >25 years, belonging to key populations, substance use and being in advanced clinical stages were more likely to be associated with partner non-testing. Non-disclosure of HIV status (due to fear of marital discord) and lack of awareness and risk perception were the key barriers to testing. Conclusion: One third of PLHIV did not have their partners tested for HIV. Several factors were identified as being associated with the non-testing of partners, and solutions were explored that need to be implemented urgently if we are to achieve the 90-90-90 targets and end HIV.

Approaching Perfection: New Developments in Zebrafish Genome Engineering

Programmable nucleases have revolutionized zebrafish genetics by enabling targeted genome modifications. In this issue of Developmental Cell, Hoshijima et al. (2016) take genome modification in the zebrafish to the next level, demonstrating the efficient use of homologous recombination to make genetic tools for a range of applications.

Targeted candidate gene screens using CRISPR/Cas9 technology

In the postgenomic era, the ability to quickly, efficiently, and inexpensively assign function to the zebrafish proteome is critical. Clustered regularly interspaced short palindromic repeats (CRISPRs) have revolutionized the ability to perform reverse genetics because of its simplicity and broad applicability. The CRISPR system is composed of an engineered, gene-specific single guide RNA (sgRNA) and a Cas9 enzyme that causes double-stranded breaks in DNA at the targeted site. This simple, two-part system, when injected into one-cell stage zebrafish embryos, efficiently mutates target loci at a frequency such that injected embryos phenocopy known mutant phenotypes. This property allows for CRISPR-based F0 screening in zebrafish, which provides a means to screen through a large number of candidate genes for their role in a phenotype of interest. While there are important considerations for any successful genetic screen, CRISPR screening has significant benefits over conventional methods and can be accomplished in any lab with modest molecular biology experience.

Rapid reverse genetic screening using CRISPR in zebrafish

Identifying genes involved in biological processes is critical for understanding the molecular building blocks of life. We used engineered CRISPR (clustered regularly interspaced short palindromic repeats) to efficiently mutate specific loci in zebrafish (Danio rerio) and screen for genes involved in vertebrate biological processes. We found that increasing CRISPR efficiency by injecting optimized amounts of Cas9-encoding mRNA and multiplexing single guide RNAs (sgRNAs) allowed for phenocopy of known mutants across many phenotypes in embryos. We performed a proof-of-concept screen in which we used intersecting, multiplexed pool injections to examine 48 loci and identified two new genes involved in electrical-synapse formation. By deep sequencing target loci, we found that 90% of the genes were effectively screened. We conclude that CRISPR can be used as a powerful reverse genetic screening strategy in vivo in a vertebrate system.

Rapid identification and recovery of ENU-induced mutations with next-generation sequencing and Paired-End Low-Error analysis

BACKGROUND

Targeting Induced Local Lesions IN Genomes (TILLING) is a reverse genetics approach to directly identify point mutations in specific genes of interest in genomic DNA from a large chemically mutagenized population. Classical TILLING processes, based on enzymatic detection of mutations in heteroduplex PCR amplicons, are slow and labor intensive.

RESULTS

Here we describe a new TILLING strategy in zebrafish using direct next generation sequencing (NGS) of 250 bp amplicons followed by Paired-End Low-Error (PELE) sequence analysis. By pooling a genomic DNA library made from over 9,000 N-ethyl-N-nitrosourea (ENU) mutagenized F1 fish into 32 equal pools of 288 fish, each with a unique Illumina barcode, we reduce the complexity of the template to a level at which we can detect mutations that occur in a single heterozygous fish in the entire library. MiSeq sequencing generates 250 base-pair overlapping paired-end reads, and PELE analysis aligns the overlapping sequences to each other and filters out any imperfect matches, thereby eliminating variants introduced during the sequencing process. We find that this filtering step reduces the number of false positive calls 50-fold without loss of true variant calls. After PELE we were able to validate 61.5% of the mutant calls that occurred at a frequency between 1 mutant call:100 wildtype calls and 1 mutant call:1000 wildtype calls in a pool of 288 fish. We then use high-resolution melt analysis to identify the single heterozygous mutation carrier in the 288-fish pool in which the mutation was identified.

CONCLUSIONS

Using this NGS-TILLING protocol we validated 28 nonsense or splice site mutations in 20 genes, at a two-fold higher efficiency than using traditional Cel1 screening. We conclude that this approach significantly increases screening efficiency and accuracy at reduced cost and can be applied in a wide range of organisms.

Neurobeachin is required postsynaptically for electrical and chemical synapse formation

BACKGROUND

Neural networks and their function are defined by synapses, which are adhesions specialized for intercellular communication that can be either chemical or electrical. At chemical synapses, transmission between neurons is mediated by neurotransmitters, whereas at electrical synapses, direct ionic and metabolic coupling occur via gap junctions between neurons. The molecular pathways required for electrical synaptogenesis are not well understood, and whether they share mechanisms of formation with chemical synapses is not clear.

RESULTS

Here, using a forward genetic screen in zebrafish, we find that the autism-associated gene neurobeachin (nbea), which encodes a BEACH-domain-containing protein implicated in endomembrane trafficking, is required for both electrical and chemical synapse formation. Additionally, we find that nbea is dispensable for axonal formation and early dendritic outgrowth but is required to maintain dendritic complexity. These synaptic and morphological defects correlate with deficiencies in behavioral performance. Using chimeric animals in which individually identifiable neurons are either mutant or wild-type, we find that Nbea is necessary and sufficient autonomously in the postsynaptic neuron for both synapse formation and dendritic arborization.

CONCLUSIONS

Our data identify a surprising link between electrical and chemical synapse formation and show that Nbea acts as a critical regulator in the postsynaptic neuron for the coordination of dendritic morphology with synaptogenesis.

Early outcome of second line antiretroviral therapy in treatment-experienced human immunodeficiency virus positive patients

PURPOSE AND AIM

Multi-drug resistance in treatment-experienced human immune deficiency virus (HIV) patients has been a major cause to first line antiretroviral therapy (ART) failure, necessitating a switch to second line therapy. In India, the second line treatment program is still relatively new with little experience and unclear outcomes. It is therefore, critical to assess the clinical, virological and immunological effectiveness and treatment outcome over the 1(st) year of follow-up in the patients' switched to the second line ART at public sector tertiary care center.

MATERIALS AND METHODS

A prospective, observational study was carried out on HIV positive patients switched on second line ART from January 2010 to December 2010 at ART Centre, Civil Hospital, Ahmedabad. Demographic details, symptoms, adverse drug reactions (ADRs), second line ART regimens, CD4 count, and plasma viral load (PVL) were recorded in a case record form. Patients were followed-up monthly for 12 months. The data was analyzed by t-test, z-test, and Fisher-exact test.

RESULTS

Out of 126 patients, 82 received regimen V [zidovudine (ZDV) + lamivudine (3TC) + tenofovir (TDF) + boosted lopinavir (LPV/r)] and 44 received regimen Va [3TC + TDF + LPV/r]. A significant (P < 0.0001) increase in mean body weight and marked reduction in number of patients (7) categorized as WHO stage III/IV was observed at 12 months of second line ART. Moreover, a significant immune reconstitution with increase in mean CD4 count and viral suppression (PVL < 400 copies/ml) in 103 (82%) patients (P < 0.0001) was also observed. A total of 83 ADRs were observed in 69 (55%) patients, the most common being dyslipidemia (57) followed by anemia (9).

CONCLUSION

Early treatment outcome with second line ART was good with 82% success rate in treatment experienced HIV patients. Dyslipidemia and anemia were the common ADRs observed.

RNA-seq-based mapping and candidate identification of mutations from forward genetic screens

Forward genetic screens have elucidated molecular pathways required for innumerable aspects of life; however, identifying the causal mutations from such screens has long been the bottleneck in the process, particularly in vertebrates. We have developed an RNA-seq-based approach that identifies both the region of the genome linked to a mutation and candidate lesions that may be causal for the phenotype of interest. We show that our method successfully identifies zebrafish mutations that cause nonsense or missense changes to codons, alter transcript splicing, or alter gene expression levels. Furthermore, we develop an easily accessible bioinformatics pipeline allowing for implementation of all steps of the method. Overall, we show that RNA-seq is a fast, reliable, and cost-effective method to map and identify mutations that will greatly facilitate the power of forward genetics in vertebrate models.

Ocular loiasis in London 2008-2009: a case series

PURPOSE

To report three cases of Loa loa infestation presenting over the course of 12 months to ophthalmology departments in the South West Thames region around London.

METHODS

Case series (three case histories are described) and literature review.

RESULTS

All three patients had a history of travel to West Africa. All had worms surgically removed and were referred to an infectious diseases hospital, where these were confirmed as adult Loa loa nematodes and treatment was initiated.

CONCLUSIONS

Although ocular loiasis is endemic in West Africa, European ophthalmologists in areas of diverse ethnicity should be aware that it is presenting increasingly frequently, that there is often no history of recent travel abroad, and that loiasis is a differential diagnosis for any 'at-risk' patient with an unexplained foreign body sensation.

Malakoplakia of the kidney--a case report

Malakoplakia is a rare disease expressed as a special type of inflammatory reaction to infection with various bacteria and fungi. We present a case of renal malakoplakia in a 30-year-old female patient. The symptoms were not characteristic enough for making the ture diagnosis preoperatively. A preoperative diagnosis of renal cell carcinoma was made in this case.

Gender-related differences in acute rehabilitation lengths of stay, charges, and functional outcomes for a matched sample with spinal cord injury: a multicenter investigation

OBJECTIVE

To examine the effects of gender on length of stay (LOS), treatment costs, and outcomes by using a matched sample of patients with spinal cord injury (SCI).

DESIGN

A 2 x (15 x 3) mixed, block design was used retrospectively to analyze the impact of gender on subjects matched for age, American Spinal Injury Association (ASIA) motor impairment classification, and level of neurologic injury.

SETTING

Twenty medical centers in the federally sponsored Spinal Cord Injury Model Systems project.

PARTICIPANTS

One thousand seventy-four adult patients with SCI admitted between 1988 and 1998 were assessed at acute-care admission, inpatient rehabilitation admission, and inpatient rehabilitation discharge.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

ASIA motor index and FIM instrument admission, discharge, and efficiency scores; rehabilitation LOS and medical care charges; and discharge disposition.

RESULTS

Analysis revealed no gender-related differences in FIM motor scores on admission and discharge. No differences in FIM motor efficiencies or daily change were observed. No significant differences were found for ASIA motor scores on acute-care admission and rehabilitation discharge. No differences in acute rehabilitation LOS and charges were observed. No gender-related differences were seen in the likelihood of discharge to an institutional setting.

CONCLUSION

Gender was not a significant factor in functional outcome of SCI patients after acute rehabilitation.

Molecular cloning and sequence analysis of the complestatin biosynthetic gene cluster

Streptomyces lavendulae produces complestatin, a cyclic peptide natural product that antagonizes pharmacologically relevant protein-protein interactions including formation of the C4b,2b complex in the complement cascade and gp120-CD4 binding in the HIV life cycle. Complestatin, a member of the vancomycin group of natural products, consists of an alpha-ketoacyl hexapeptide backbone modified by oxidative phenolic couplings and halogenations. The entire complestatin biosynthetic and regulatory gene cluster spanning ca. 50 kb was cloned and sequenced. It consisted of 16 ORFs, encoding proteins homologous to nonribosomal peptide synthetases, cytochrome P450-related oxidases, ferredoxins, nonheme halogenases, four enzymes involved in 4-hydroxyphenylglycine (Hpg) biosynthesis, transcriptional regulators, and ABC transporters. The nonribosomal peptide synthetase consisted of a priming module, six extending modules, and a terminal thioesterase; their arrangement and domain content was entirely consistent with functions required for the biosynthesis of a heptapeptide or alpha-ketoacyl hexapeptide backbone. Two oxidase genes were proposed to be responsible for the construction of the unique aryl-ether-aryl-aryl linkage on the linear heptapeptide intermediate. Hpg, 3,5-dichloro-Hpg, and 3,5-dichloro-hydroxybenzoylformate are unusual building blocks that repesent five of the seven requisite monomers in the complestatin peptide. Heterologous expression and biochemical analysis of 4-hydroxyphenylglycine transaminon confirmed its role as an aminotransferase responsible for formation of all three precursors. The close similarity but functional divergence between complestatin and chloroeremomycin biosynthetic genes also presents a unique opportunity for the construction of hybrid vancomycin-type antibiotics.

Safety and efficacy of currently available fibrin tissue adhesives

PURPOSE

The purpose of this study is to review preparation methods, bonding power, preparation time, and costs associated with currently available autologous and homologous fibrin tissue adhesive preparations.

METHODS

Two autologous fibrin tissue adhesive preparations (AFTA-A and AFTA-E), a single-donor homologous preparation, and 2 multiple-donor pooled homologous fibrin tissue adhesives, Vi-Guard and Tisseel, were evaluated and compared in relation to bonding power, preparation time, cost, bicompatibility, and biodegradability.

RESULTS

Vi-Guard and Tisseel showed significantly greater bonding strengths than their single-donor counterparts. AFTA-C offers the quickest preparation time. All preparations were found to be similar in biocompatibility and biodegradability in soft tissue tests. Histology showed no infection or tissue reaction from adhesive exposure in any of the preparations.

CONCLUSION

The optimal choice of a fibrin tissue adhesive is determined by the particular clinical indication. Currently available fibrin tissue adhesives vary appreciably in their bonding strength, cost, level of exposure risk, and preparation methods and times. Autologous preparations, which offer optimal safety, lack the strength and availability characteristics found with the multiple-donor preparations.

Cloning, nucleotide sequence, and heterologous expression of the biosynthetic gene cluster for R1128, a non-steroidal estrogen receptor antagonist. Insights into an unusual priming mechanism

R1128 substances are anthraquinone natural products that were previously reported as non-steroidal estrogen receptor antagonists with in vitro and in vivo potency approaching that of tamoxifen. From a biosynthetic viewpoint, these polyketides possess structurally interesting features such as an unusual primer unit that are absent in the well studied anthracyclic and tetracyclic natural products. The entire R1128 gene cluster was cloned and expressed in Streptomyces lividans, a genetically well developed heterologous host. In addition to R1128C, a novel optically active natural product, designated HU235, was isolated. Nucleotide sequence analysis of the biosynthetic gene cluster revealed genes encoding two ketosynthases, a chain length factor, an acyl transferase, three acetyl-CoA carboxylase subunits, two cyclases, two oxygenases, an amidase, and remarkably, two acyl carrier proteins. Feeding studies indicate that the unusual 4-methylvaleryl side chain of R1128C is derived from valine. Together with the absence of a dedicated ketoreductase, dehydratase, or enoylreductase within the R1128 gene cluster, this suggests a functional link between fatty acid biosynthesis and R1128 biosynthesis in the engineered host. Specifically, we propose that the R1128 synthase recruits four subunits from the endogenous fatty acid synthase during the biosynthesis of this family of pharmacologically significant natural products.

Kinetic analysis of the actinorhodin aromatic polyketide synthase

Type II polyketide synthases (PKSs) are bacterial multienzyme systems that catalyze the biosynthesis of a broad range of natural products. A core set of subunits, consisting of a ketosynthase, a chain length factor, an acyl carrier protein (ACP) and possibly a malonyl CoA:ACP transacylase (MAT) forms a "minimal" PKS. They generate a poly-beta-ketone backbone of a specified length from malonyl-CoA derived building blocks. Here we (a) report on the kinetic properties of the actinorhodin minimal PKS, and (b) present further data in support of the requirement of the MAT. Kinetic analysis showed that the apoACP is a competitive inhibitor of minimal PKS activity, demonstrating the importance of protein-protein interactions between the polypeptide moiety of the ACP and the remainder of the minimal PKS. In further support of the requirement of MAT for PKS activity, two new findings are presented. First, we observe hyperbolic dependence of PKS activity on MAT concentration, saturating at very low amounts (half-maximal rate at 19.7 +/- 5.1 nM). Since MAT can support PKS activity at less than 1/100 the typical concentration of the ACP and ketosynthase/chain length factor components, it is difficult to rule out the presence of trace quantities of MAT in a PKS reaction mixture. Second, an S97A mutant was constructed at the nucleophilic active site of the MAT. Not only can this mutant protein support PKS activity, it is also covalently labeled by [(14)C]malonyl-CoA, demonstrating that the serine nucleophile (which has been the target of PMSF inhibition in earlier studies) is dispensible for MAT activity in a Type II PKS system.

A newly recognized entity: intraductal "oncocytic" papillary neoplasm of the pancreas

Intraductal papillary-mucinous tumors of the pancreas are increasingly recognized, and their characteristic endoscopic and radiological features are well reported in the literature in recent years. Oncocytic features in these tumors are uncommon and unrecognized. Intraductal oncocytic papillary neoplasm is a distinct pancreatic tumor and is a recently recognized entity. We report a case of a 69-yr-old patient who presented with symptoms mimicking pancreatitis, resulting in delay in the diagnosis of her pancreatic tumor. She underwent a successful Whipple's procedure and subsequently has remained well. The resected specimen showed an intraductal oncocytic papillary-mucinous neoplasm. The entity is new and the literature information is inadequate at present to judge the biological behavior of this tumor. We discuss this recently recognized entity.

Prevalence of Helicobacter pylori in peptic ulcer patients in greater Rochester, NY: is empirical triple therapy justified?

OBJECTIVES

Among patients with peptic ulcer disease, the prevalence of Helicobacter pylori has been reported to range from 80% to 90%. Thus empirical cost-effective therapy has been suggested. We surveyed patients with peptic ulcer disease in Rochester, NY.

METHODS

From two teaching hospitals all patients who had duodenal ulcers (DU) and/or gastric ulcers (GU) on esophagogastroduodenoscopy (EGD) with antral biopsy for histology for H. pylori and for rapid urease (CLO) test were included in the study. We examined a total of 160 patients with DU and 145 patients with GU, age range 18-92 yr, obtaining clinical data, race, medication profile, and history of use of nonsteroidal antiinflammatory drugs (NSAIDs). An ulcer was defined if the lesion with loss of mucosal integrity was > or = 0.5 cm, with apparent depth. H. pylori was considered present if CLO test and/or histology were positive for H. pylori. To confirm the reliability of nonuse of NSAIDs, we randomly checked blood samples of 90 such patients from the ambulatory clinic for the presence of salicylates. To identify the sensitivity of the CLO test, we performed a serology test for H. pylori antibody in 100 subjects to compare the CLO test results. Also, 500 CLO test results were compared to the histology results for H. pylori.

RESULTS

Among 160 DU patients, 16 were NSAID users with negative H. pylori and excluded from the prevalence study. Of the remaining 144 patients with DU, H. pylori was present in 88 patients (61%). When these data were analyzed according to race, H. pylori was present in 54 (52%) of 104 whites compared to 34 of 40 (85%) nonwhites (blacks, Hispanics, Asians) (p < 0.01). Among 145 GU patients 18 were NSAID users with negative H. pylori and excluded from the prevalence analysis. Of the remaining 127 patients with GU, H. pylori was present in 87 patients (61%). Among them, H. pylori was present in 46 of 87 (53%) whites, whereas 31 of 40 nonwhites (78%) were H. pylori-positive (p < 0.01). Antral histology and CLO test for H. pylori were in agreement in 92% of cases. Serology and CLO test for H. pylori were in agreement in 87% of cases. None of the randomly screened patients, including 16 ulcer patients with negative H. pylori, showed presence of salicylate in blood.

CONCLUSION

In greater Rochester, NY, where the majority of our patients with EGD were whites, the prevalence of H. pylori among ulcer patients was lower compared to other regions, particularly among whites. This suggests that an additional causative factor or factors for peptic ulcers may be present. Hence, empirical antibiotic therapy of ulcer patients without confirming the presence of H. pylori may not be justified.

Thermodynamic characterization of the reversible, two-state unfolding of maltose binding protein, a large two-domain protein

The folding and stability of maltose binding protein (MBP) have been investigated as a function of pH and temperature by intrinsic tryptophan fluorescence, far- and near-UV circular dichroism, and high-sensitivity differential scanning calorimetric measurements. MBP is a monomeric, two-domain protein containing 370 amino acids. The protein is stable in the pH range of 4-10.5 at 25 degrees C. The protein exhibits reversible, two-state, thermal and guanidine hydrochloride-mediated denaturation at neutral pH. The thermostability of MBP is maximal at pH 6, with a Tm of 64.9 degrees C and a deltaHm of 259.7 kcal mol(-1). The linear dependence of deltaHm on Tm was used to estimate a value of deltaCp of 7.9 kcal mol(-1) K(-1) or 21.3 cal (mol of residue)(-1) K(-1). These values are higher than the corresponding deltaCp's for most globular proteins studied to date. However, the extrapolated values of deltaH and deltaS (per mole of residue) at 110 degrees C are similar to those of other globular proteins. These data have been used to show that the temperature at which a protein undergoes cold denaturation depends primarily on the deltaCp (per mol of residue) and that this temperature increases with an increase in deltaCp. The predicted decrease in stability of MBP at low temperatures was experimentally confirmed by carrying out denaturant-mediated unfolding studies at neutral pH at 2 and 28 degrees C.

Bacterial culture and sensitivity in pemphigus

Infection is the commonest cause of death in pemphigus and the commonest infection is Staphylococcus aureus bacteremia. In present study bacterial culture and sensitivity from the lesion was done in 25 patients of pemphigus vulgaris and accordingly antibiotics were given along with other treatment of pemphigus i.e. steroid, immunosuppressive drug etc. Most common pathogenic bacteria isolated was Staphylococcus aureus and it was sensitive to cloxacillin, erythromycin, cefotaxime and lincomycin.

A survey of sunbathing practices on three Connecticut State beaches

In order to analyze sunbathing practices, a survey was conducted during the summer of 1995 on three Connecticut state beaches, with 1,003 interviews completed. The majority (65.8%) of respondents were women. Almost 70% of respondents were visiting the beach to get or maintain a tan. While the intended beach stay averaged four hours, only 55.7% of respondents were using sunscreen, 6.9% were sitting under shade, 12.7% were wearing hats, and 17.1% were wearing clothes other than a bathing suit. More than half (55%) of the sunscreen used had a sun protection factor of less than 15. Children were provided with greater protection than adults. The survey indicates the need for greater educational efforts to motivate protective behavior. Primary-care physicians could have an important role in these efforts.

Parathyroid adenomas: accurate detection and localization with Tc-99m sestamibi SPECT

PURPOSE

To evaluate the ability to detect and localize parathyroid adenomas with technetium-99m sestamibi single photon emission computed tomography (SPECT).

MATERIALS AND METHODS

Forty-seven adult patients underwent Tc-99m sestamibi SPECT. Early (15-30 minutes after injection) and delayed (2-4 hours after injection) images were acquired. Thirty-three patients were examined for initial parathyroid surgery; the remaining 14, for repeat surgery because of persistent or recurrent hyperparathyroidism. SPECT reprojection images viewed in a rotating cine-display mode were read independently by two nuclear medicine physicians who were blinded to the results of other localization studies. Thirty-seven patients underwent subsequent neck exploration. SPECT findings were compared with surgical and histopathologic findings.

RESULTS

In the 37 patients who underwent surgery, parathyroid adenomas were confirmed in 34 (92%) and hyperplasia in three (8%). In 31 patients, adenomas were correctly detected and localized with early SPECT images (sensitivity, 91%). In contrast, the sensitivity of delayed SPECT images was 74% (25 of 34 patients) for detection and 32% (11 of 34 patients) for localization. Early SPECT images were significantly better for localization (P < .001) and detection (P = .03).

CONCLUSION

For Tc-99m sestamibi parathyroid imaging, early SPECT images were the most accurate in the detection and localization of parathyroid adenomas.

A wandering spleen. Detection by In-111 leukocyte imaging

A wandering spleen is a rare condition characterized by splenic malposition due to congenital maldevelopment or laxity of the supporting ligamentous structures that usually fixate the anatomical position of the spleen. The diagnosis is often difficult to make clinically. In this report, a case is described in which an In-111 oxime labeled leukocyte scan was helpful in making a diagnosis of a wandering spleen.

The cause of death in inflammatory bowel disease: a comparison of death certificates and hospital charts in Rochester, New York

OBJECTIVE

This study examines the causes of death from Crohn's disease and ulcerative colitis by comparing death certificates with hospital charts as part of an ongoing, community-based analysis in Rochester, NY.

METHODS

A registry of 1358 inflammatory bowel disease patients followed from January 1973 to December 1989 was analyzed for the cause of death by a study of death certificates as well as by a study of hospital records, including surgical pathology and autopsy records. A panel of physicians defined specific criteria for diagnosis, cause of death, and relation of death to inflammatory bowel disease.

RESULTS

One hundred and thirty patients (59 with ulcerative colitis and 71 with Crohn's disease) from the registry were found to have death certificates recorded by Monroe County during this period. There was an 80% concordance of the death certificate to the hospital record for the cause of death and its relationship to inflammatory bowel disease. Discordance was noted in cases of colon cancer and surgical complications.

CONCLUSIONS

Sixty-eight percent of Crohn's disease and 78% of ulcerative colitis patients died from causes unrelated to their inflammatory bowel disease. Deaths caused by Crohn's disease decreased from 44% in the 1973-1980 period to 6% in the 1981-1989 period. Crohn's disease was a direct cause of death in 25% of the female patients, whereas only 6% of male patients died directly of Crohn's disease. Colorectal cancer caused 14% of the deaths in ulcerative colitis patients, three times more often than in Crohn's disease patients. Excluding cancer, there were only two deaths directly due to ulcerative colitis, both in the first 2 yr after diagnosis.

Radionuclide imaging in organ transplantation

This article addresses the utility of radionuclide imaging for evaluating functional and anatomic integrity of transplanted liver, kidney, pancreas, heart, and lung. Information about how to interpret routine nuclear medicine procedures for vascular and surgical complications as well as rejection after transplantation is also presented. The role of new radiopharmaceuticals is discussed briefly.

Role of nuclear medicine in liver transplantation

Orthotopic liver transplantation is now a very well-established technique for treating patients with end-stage liver disease. Since 1967, more than 26,000 liver transplants have been performed, including 15,000 in the United States. The overall 1-year survival rate is approximately 80% and 5-year survival is 70%. Nuclear imaging plays an important role in the management of liver transplant recipients before and after liver transplantation. The evaluation of candidates potentially includes liver-spleen scan for liver volume, multiple gated acquisition scan, adenosine or stress thallium study, bone scan, and quantitative ventilation perfusion scan for hepatopulmonary syndrome. In the post-transplant phase, the deconvolution analysis (which corrects for the problem of recirculation) is a promising tool for diagnosing rejection, although its role in the transplant population has to be established. A variety of nuclear medicine techniques are helpful in the postoperative diagnosis of biliary complications. By performing a semiquantitative analysis to discriminate hepatocyte dysfunction from biliary disease and measuring hepatocyte extraction fraction by deconvolution analysis and excretion, (T1/2 values measured by the nonlinear list squares technique) have been very promising.

Bilateral pigmented hairy epidermal naevus

A 15-year-old boy developed bilateral Becker's naevus over scapular region without any associated abnormality.

Langerhans cell histiocytosis

A case of Langerhans Cell Histiocytosis (LCH) is reported in 1½ years old boy. He had seborrhoeic dermatitis like condition of scalp, papular lesions with purpura typical of Letterer-Siwe disease associated with constitutional symptoms, hepatosplenomegaly, jaundice, anaemia and thrombocytopenia. Peripheral blood film and bone marrow examination showed presence of LCH cells.

Indications for and results of single, bilateral, and heart-lung transplantation for pulmonary hypertension

The indications for single, bilateral, and heart-lung transplantation for patients with pulmonary hypertension remain controversial. We retrospectively analyzed the results from 11 single, 22 bilateral, and 24 heart-lung transplant procedures performed between January 1989 and January 1993 on 57 consecutive patients with pulmonary hypertension caused by primary pulmonary hypertension (n = 27) or Eisenmenger's syndrome (n = 30). Candidates with a left ventricular ejection fraction less than 35%, coronary artery disease, or Eisenmenger's syndrome caused by surgically irreparable complex congenital heart disease received heart-lung transplantation. All other candidates received single or bilateral lung transplantation according to donor availability. Although postoperative pulmonary artery pressures decreased in all three allograft groups, those in single lung recipients remained significantly higher than those in bilateral and heart-lung recipients. The cardiac index improved significantly in only the bilateral and heart-lung transplant recipients. A significant ventilation/perfusion mismatch occurred in the single lung recipients as compared with bilateral and heart-lung recipients because of preferential blood flow to the allograft. Graft-related mortality was significantly higher and overall functional recovery as assessed by New York Heart Association functional class was significantly lower at 1 year in the single as compared with bilateral and heart-lung recipients. Thus bilateral lung transplantation may be a more satisfactory option for patients with pulmonary hypertension with simple congenital heart disease, absent coronary arterial disease, and preserved left ventricular function. Other candidates will still require heart-lung transplantation.